DETECTORS
Including Codes of Practice2015

IONIZING RADIATIONPTW History and General Remarks

Looking back on
a long history…
PTW-Freiburg is an internationally operating company, manufacturing and marketing specialized dosimetry and quality control equipment for the medical radiology and health physics market. Founded
in 1922, the company is located in Freiburg on the western side of
the famous Black Forest mountains in southwestern Germany.

Our Operations
PTW-Freiburg designs, develops, manufactures and distributes highquality dosimetry and QC equipment mainly for use in the medical
field, especially in radiation therapy, diagnostic radiology and nuclear
medicine. The development and production of mechanical,
electronic and software components are all done in house. Our
products, especially the PTW ionization chambers, are well known
throughout the world and are recognized for their workmanshipand high level of quality. PTW-Freiburg is the market leader in its
major product lines. The PTW distribution is organized internationally. A number of daughter companies and exclusive PTW representations are established in many countries around the world. We
cooperate closely with official public agencies worldwide, and weparticipate actively in national and international work groups for the
standardization of devices and procedures for dose measurement
and quality control in radiation medicine.

Our History
In 1922, twenty-seven years after Röntgen discovered the X-rays,
Professor Hammer from the Physics Institute of Freiburg University
founded PTW to produce and market his development of an X-ray
dosemeter based on the electrostatic relais, a revolutionary newelectromechanical component for measuring very small electricalcharges. In 1927, Dr. Herbert Pychlau took over the company anddeveloped it during four decades into an internationally recognizedmanufacturer of quality dosemeters for medical radiology. PTW has
developed and manufactured many generations of up-to-date
products over the years, based on the newest technology. The company has grown continuously. Today, PTW employs a staff of morethan 230 all over the world.

The evolvement of radiation detectors
1922 Compact chambers with fixed preamplifier Hammer Dosimeter
1927 Barrel type chambers as secondary transfer standards
Küstner Dosimeter
1928 Shadow-free chambers
Schattenfreie Kammer
1930 Pressurized radiation protection chambers Streustrahlenkammer
1932 Continuous monitoring therapy chambers
Tubusrelais
1933 Water protected chambers for water phantom use
Wasserphantom
1933 Capacitor chambers for „wireless“ measurement
Ionognom
1936 Waterproof sealed chambers for brachytherapy
Mikrokammern
1950 Flat chambers for diagnostic radiology and mammography
Flachkammern
1959 Transparent chambers for dose area product measurement
DIAMENTOR ®
1971 Pressurized well type chambers for nuclear medicine
CURIEMENTOR ®
1977 Plane-parallel low energy chambers
Soft X-ray Chambers
1980 Dedicated electron chamber
Markus Chamber1985 Single and multiple detectors for brachytherapy AM6 Detectors
1989 Pencil chamber for computed tomography
CT Chamber
1993 Diamond detector for water phantom use Diamond Detector
1995 Liquid filled ionization chamber linear array
LA 48 Array
1995 Diode detectors for diagnostic radiology
DIADOS Detectors
1996 Well type chambers for brachytherapy source measurement
HDR Chambers
1997 Ultracompact ionization chambers
PinPoint Chambers
1999 Dosimetry diodes for water phantom use
Dosimetry Diodes
2002 4π flat chamber for seed measurement
SourceCheck
2003 2D ionization chamber array
2D-ARRAY seven29
2005 Ultracompact chamber with 3D characteristics
PinPoint 3D Chamber2005 Dedicated proton chamber
Bragg Peak Chamber
2008 High resolution chamber matrix
STARCHECK2009 Fullsize high resolution chamber matrix
STARCHECK maxi
2012 Liquid filled 2D ionization chamber array
OCTAVIUS Detector 1000 SRS
2013 First synthetic diamond detector (SCDD)
microDiamond

General Remarks
1. All air filled ionization chambers described in this catalog are shipped with a PTW calibration certificate for one measuring quantity(please specify), valid for the stated reference radiation quality.
2. An instruction manual in English is included with every detector.
3. The cable length of the detectors is 1 m, if not stated otherwise.
4. All detectors in this catalog can be operated with a PTW extension cable up to 100 m in length.
5. For very accurate measurements a pre-irradiation dose of (1 ... 3) Gy is recommended for all therapy ionization chambers,
even if the data sheet does not specify a mandatory pre-irradiation dose.
6. In case a detector is not used together with a PTW electrometer, the user must ensure that the polarizing voltage is applied by acurrent-limiting device with a maximum current of 0.5 mA.
7. Most detectors in this catalog are available with 3 different connecting systems (BNT, TNC and M type).
8. All technical data published in this catalog are typical data for the various detector types.
Certain data of individual detectors may vary slightly within the ranges of tolerance.

2

Ionizing Radiation Detectors: Contents

Contents
Introduction

4

Therapy Detectors

9Diagnostic Detectors

37

Health Physics Detectors

45

Quick View

57

Codes of Practice

73

Index

99

3

The Physics

The Physics
General Aspects
Radiation detectors convert radiation energy into electrical energy. The electrical signal of a detector whenirradiated is measured by an electrometer connected to the detector. By applying a certain detector specificcalibration factor (e.g. Gy/C), the detector signal is related to a radiation dose value. Further correction factors
depending on the detector characteristics and the beam quality may be used. A variety of detector types withdifferent design for intensity measurements of ionizing radiation is available. The radiation detection for dosimetric purposes in the medical field of diagnostic radiology, radiotherapy and nuclear medicine is mainly based on
three principles of measurement, realized by three different detector types: the ionization chamber, the semiconductor detector and the diamond detector.

Ionization Chamber
An ionization chamber basically consists of a gas
volume between two electrodes connected to a highvoltage supply of typically 100 V to 1000 V. In thisgas volume ionizing radiation creates ion pairs. These,
being positive and negative charge carriers, are attracted by the electrodes thus creating a current which canbe measured by an electrometer. Gas (air) volumes varyfrom 0.01 cm3 to 10,000 cm3, corresponding currents
can be between 10-14 A and 10-7 A. Using non-polar
fluids, liquid-filled ionization chambers can be realized.

Semiconductor Detector
In silicon semiconductors a layer of n-type silicon isbrought into contact with a layer of p-type silicon,allowing electrons to drift from the n to the p region of
the detector thus creating an insulating intrinsic zone.
Incident radiation frees electrons in the intrinsic zone
(sensitive layer of the detector) which move to the positively charged p region, generating a current. This solar
cell principle does not need an external bias voltage.

Diamond Detector
A high purity diamond can operate as a solid stateionization detector. Ionizing radiation can push electrons from the valence band to higher energy levels
thereby first filling electron traps caused by impurities
and then bringing electrons to the conductivity band.
An external bias is needed to produce an ionization
current very much like in an ionization chamber. A stable current can only be measured though after sufficient pre-irradiation to fill the traps.

4

The Detector Design

The Detector Design
Thimble Ionization Chamber
A thimble chamber (also known as compact chamber)consists of a central electrode and a cylindrical chamber wall with a spherical or conical end mounted on acylindrical stem. A guard on central electrode potential leading up to the sensitive volume limits dark currents and stem effects.

Plane-Parallel Ionization Chamber
A plane-parallel chamber (also known as flat chamber)consists of a high voltage electrode plate and a measuring electrode plate confining the sensitive volume.
A guard on central electrode potential around themeasuring electrode plate limits dark current and perturbation effect.

Spherical Ionization Chamber
A spherical chamber consists of two concentric balls
representing the central measuring electrode and thechamber wall and confining the sensitive volume. A
guard on central electrode potential around the measuring electrode stem limits the dark current.

Well-Type Ionization Chamber
A well-type chamber consists of an outer housing withan inset cylindrical cavity – representing the chamber
wall – to receive the measuring object. The measuring
electrode also surrounds this cavity. A guard on central
electrode potential around the measuring electrodestem limits the dark current.

Semiconductor Detector
A silicon semiconductor detector consists of a layered
silicon disk with contact wires to the measuring instrument. This is embedded horizontally or vertically inprotective and / or build-up material depending on theintended application to form a useful probe.
This detector does not need an external bias voltage
nor a guard.

Diamond Detector
A diamond detector consists of a diamond disk withcontact wires to the measuring instrument. This isembedded vertically in water-equivalent protective
material to produce a probe with the highest possible
spatial resolution in axial direction for use in therapy
beam analysis. A guard is lead up to the detector stem.

5

PTW Calibration Laboratory

PTW Calibration Laboratory
As both the oldest and the largest manufacturer ofionization chambers and medical dosimetry equipment, PTW-Freiburg has always maintained a calibration laboratory for dosimetric measuring quantities.
While being an integral part of the company and a key
component of the PTW-Freiburg comprehensive quality assurance system, the calibration laboratory is alsoproud of its very own traditions and achievements. The
PTW Calibration Laboratory as an independent functional unit today is recognized internationally as one of
the leading Secondary Standard Dosimetry
Laboratories of the world.

improved versions of the Küstner Transfer Standard
instrument in the PTW museum bear witness of thattradition. Internal traceability is proudly extended tothe point of preserving the original measurement
notes to every calibration performed since 1937. This
traditional approach to quality today gives the laboratory the advantage of access to what is probably thelargest database on calibrations of clinical dosimetry in
the world.

Calibration facilities andinstrumentation
Our facility is one of the largest, most modern commercial ionizing radiation calibration lab and repair
facility in the world. In 2008 the space for the calibration lab is enlarged up to 900 sq. meters. Today the
PTW calibration laboratory operates ten separate calibration benches for radiological and radiotherapy measurements ranging from small mammography and soft
X-ray facilities up to 137Cs and the 74 TBq (2000 Ci)
60Co radiotherapy standard. Work at all these single
calibration places is coordinated using a custom-madelaboratory software for process control, data acquisition from the calibration monitors (UNIDOS instru-

Front view of the PTW-Freiburg factory, building with calibration laboratory to the left. Chamber assembly building in the background

Origin and tradition
PTW-Freiburg was founded on May 9, 1922 for the
purpose of manufacturing radiation therapy dosemeters based on the electrostatic relay invented by one of
the founders, Prof. Hammer. Early photographs of thecalibration laboratory show Hammer and Küstner dosimeters and their ionization chambers facing X-ray
tubes supplied by open high-voltage leads. Calibration
traceability to the National Laboratory (first PTR, nowPTB) always was of prime importance. Original and

The building with the calibration laboratory (with solar panels)
seen from above (Photo: Bavaria Luftbild Verlags GmbH)ments) and calibration calculation for the department
office writing the calibration certificates. As far as possible (for connector compatibility) the reference class
UNIDOS electrometers are also used for the measurement of the customer chambers. The calibration inelectrical measuring quantities of all electrometers
used is also traceable to the PTB primary standard.
Besides the dose and dose rate ranges the laboratory
maintains facilities for the calibration of non-invasive
kV-meters and nuclear medicine isotope calibrators.
Detail of the calibration laboratory approx. 1957

6

PTW Calibration Laboratory

Quality and regulatory compliance
Both as part of PTW-Freiburg and as Secondary
Standard Dosimetry Laboratory the PTW Calibration
Laboratory is qualified by adherence to the most stringent QA standards. Current certifications comprise
ISO 9001-2000, ISO 13485-2003, ISO 17025, andAnnex II, Section 3 of the Directive 93/42/EEC (Medical
Device Directive).
Customers have the choice of Factory Calibration
Certificate or Secondary Standard Calibration Certificate(DAkkS) for dose / dose rate calibrations.

Scope of work
Repair and electrical calibration of measuring instruments are mainly done for PTW dosimeters. This includes complete electrical recalibration of the modern
electrometers through all their measuring ranges aswell as early fault elimination by burn-in and comprehensive electrical safety tests.
Whenever possible radiological calibrations include theadjustment of the instrument to directly display dose at
the reference quality. Radiological calibrations are performed in the measuring quantities and radiation quality
ranges as shown on page 8.
For these calibrations every instrument from every
manufacturer is accepted (as long as it works and physically fits within the beam). Special radiological calibrations are available upon request. In consequence the
PTW laboratory is one of the busiest radiological calibration laboratories worldwide with over 10000 instruments calibrated every year.

300 kV X-ray installation with filter wheel

Comparison measurements
Comparison measurements both in the form of directcomparisons in the calibration chain and ring comparisons between laboratories of equal rank are essential
in documenting and maintaining traceability for any
calibration laboratory. At the PTW Calibration Laboratory comparisons both with primary laboratories andwith other secondary standard dosimetry laboratories
are done on a regular basis. Traceability to PTB is maintained by calibration of six sets of dosimetry equipment every two years with comparative measurements and reports every three months. Comparison
with IAEA is done by exchange of mailed TLD every
year and occasional comparative measurements withionization chambers. Deviations are always minimal.
Participation in European
Ring Comparisons (mostly
also supplied with PTW
equipment) continuously
shows very successful results.
TLD comparison measurements between IAEA andPTW both using the IAEA
system and the PTW TLD
audit probes have shown
only minimal differences.
Setting up a chamber

Secondary Standard Laboratory/
Cooperation with IAEA and PTB
Having successfully participated in the regular comparisons for some years, since the year 2000 the PTW
calibration laboratory is formally recognized as a
Secondary Standard Dosimetry Laboratory in the
IAEA/WHO SSDL network[1].
This so far is the latest expression of the extremely
good and fruitful cooperation PTW has enjoyed with
the IAEA Dosimetry Laboratory. (Since 1996 PTW has
qualified and thrice requalified as preferred supplier ofclinical dosimetry equipment to IAEA.) Another positive aspect of this cooperation is in the mutual discussion of procedures and equipment which has lead to thedesign or continued development of several dosimetrycomponents as for example the PTW Farmer chambers.
A similar close cooperation is traditionally maintainedwith the German National Laboratory, PTB. Joint development has lead to such successful results as the
Böhm extrapolation chamber and the Roos electron
chamber. In the German DKD service of secondary
standard laboratories PTW was the first and only laboratory for dosimetric quantities[2]. PTW is also one ofthe oldest members of this service (since 1980).
[1] IAEA /WHO SSDL Newsletter No. 43 July 2000 page 43(http://www.iaea.or.at/programmes/nahunet/e3/dmrp_e3_pub.html)[2] Physikalisch-Technische Bundesanstalt, DKD Deutscher Kalibrierdienst,
Verzeichnis der Kalibrierlaboratorien, Ausgabe 3/2001: DKD-K-01501(http://www.dkd.ptb.de)7

PTW Calibration Laboratory

Calibration Service Radiation Qualities
Radiation Therapy Dosemeters

Miscellaneous Calibrations- X-rays
10, 15, 30, 50, 70, 100 kV(TW qualities according to DIN 6809-4)- X-rays
70, 100, 140, 200, 280 kV(TH qualities according to DIN 6809-5)- 137Cs
662 keV- 60Co
1.3 MeV- Source strength (cGym2h-1) of brachytherapy sources
measured by well-type chambers- Diagnostic X-ray generator high voltage of all types of
X-ray equipment measured non-invasively by kV-meters:
Different ranges from 20 to 150 kV- Nuclide activity in nuclear medicine measured by isotope
calibrators (only CURIEMENTOR instruments)- Electrical measuring quantities charge (C) and current (A)measured by highly sensitive electrometers

Diagnostic Radiology Dosemeters- X-rays
50, 70, 90, 120, 150 kVConventional(RQR and RQA qualities according to IEC 61267)- X-rays
70, 90, 120, 150 kVCT(RQR and RQA qualities according to IEC 61267)- X-rays
100, 120, 150 kV
CT(RQT qualities according to IEC 61267)- X-rays
50, 70, 90 kV
Dental
- X-rays25, 28, 30, 35 kV
Mammography
Qualities according to IEC 61267 Mo/Mo, Mo/Rh, Rh/Rh,
W/Ag, W/Al, W/Rh (each with 2 mm Al optional)

Radiation Protection Dosemeters- X-rays20, 30, 40 kV(Narrow Spectrum Series (N) qualities acc ISO 4037-1)- X-rays
60, 80, 100, 150, 200, 250 kV(Narrow Spectrum Series (N) qualities acc ISO 4037-1)
662 keV- 137Cs
1.3 MeV- 60Co8

General Information
According to the PTW definition, each such set of beam
qualities represents one calibration point for a certain application and can be ordered with a single order number.
For more detailed information please refer to “Calibrations
at PTW – A Short Guide” which you will find in thesection Services-Calibrations on our website www.ptw.de.

Therapy Detectors

Therapy Detectors

Therapy Detectors
Farmer Chamber (PMMA/Aluminum)

10

Farmer Chamber (Graphite/Graphite)

11

Farmer Chamber (Graphite/Aluminum)

12

Farmer Chamber, waterproof

13

Semiflex Chamber 0.125 cm3

14

Semiflex Chamber 0.3 cm315

Rigid Stem Chamber 0.3 cm3

16

Rigid Stem Chamber 1.0 cm3

17

Advanced Markus Chamber

18

Markus Chamber

19

Roos Chamber

20

Bragg Peak Chamber 10.5 cm321

Bragg Peak Chamber 2.5 cm3

22

PinPoint Chamber 0.015 cm3

23

PinPoint Chamber 0.03 cm3

24

PinPoint 3D Chamber25

microDiamond

26

Dosimetry Diode P

27

Dosimetry Diode E

28

Dosimetry Diode SRS

29

Dosimetry Diode PR

30

Soft X-Ray Chamber 0.02 cm331

Soft X-Ray Chamber 0.2 cm332

Soft X-Ray Chamber 0.005 cm3

33

SOURCECHECK 4π

34

System Incorporated Detectors

35

Radioactive Check Devices

36

9

Therapy Detectors

Farmer ChamberType 30010
Classical therapy chamber for absolute
dosimetry in high-energy photon,
electron and proton beams

Features

Acrylic wall, graphited

Materials and measures:
Wall of sensitive volume0.335 mm PMMA,
1.19 g/cm3
0.09 mm graphite,
1.85 g/cm3

Aluminum central electrodeTotal wall area density

56.5 mg/cm2

Radioactive check device (option)

Dimension of sensitive
volumeradius 3.05 mm
length 23.0 mm

Fully guarded chamber
Sensitive volume 0.6 cm3, vented to air

The 30010 Farmer chamber is a wide spread ionizationchamber for absolute dose measurements in radiation
therapy. Correction factors needed to determine
absorbed dose to water or air kerma are published in thepertinent dosimetry protocols. The acrylic chamber wall
ensures the ruggedness of the chamber. The chamber isdesigned for the use in solid state phantoms and therefore not waterproof.

Central electrode

Al 99.98, diameter 1.1 mm

Build-up cap

PMMA, thickness 4.55 mm

Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

5 Gy/s
10 Gy/sSpecification

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.46 mGy
0.91 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Type of productvented cylindrical ionizationchamber acc. IEC 60731

Application

absolute dosimetry inradiotherapy beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.6 cm3

Designnot waterproof, vented,
fully guarded

Reference point

Ion collection efficiency at nominal voltage:
Ion collection time
140 µsRadiation quality

30 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

on chamber axis, 13 mmfrom chamber tip

Air pressure(700 ... 1060) hPa

Direction of incidence

radialOrdering Information

Nominal response

20 nC/Gy

Long-term stability≤ 0.5 % per year

TN30010-1 Farmer type chamber 0.6 cm3, PMMA/Al,
connecting system BNT

Chamber voltage

400 V nominal± 500 V maximal

TW30010-1 Farmer type chamber 0.6 cm3, PMMA/Al,
connecting system TNC

Polarity effect at 60Co

< 0.5 %

Photon energy response≤ ± 2 % (70 kV ... 280 kV)≤ ± 4 % (200 kV ... 60Co)

TM30010-1 Farmer type chamber 0.6 cm3, PMMA/Al,
connecting system M

Directional response insolid state phantom≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 5°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

10

Options
T48012 Radioactive check device 90Sr
T48002.3.003 Chamber holding device for check device

Therapy Detectors

Farmer ChamberType 30011
Pure graphite therapy chamber for
absolute dosimetry in high-energy
photon, electron and proton beams

Features
Fully guarded chamber
Sensitive volume 0.6 cm3, vented to air

Materials and measures:
Wall of sensitive volume0.425 mm graphite,
1.85 g/cm3
Total wall area density

79 mg/cm2

Graphite central electrode

Dimension of sensitive
volumeradius 3.05 mm
length 23.0 mm

Radioactive check device (option)

Central electrodegraphite, diameter 1.0 mm

The 30011 all graphite Farmer chamber is used for absolute dose measurements in radiation therapy in cases
where a minimum of different materials in the radiation
field is desired. Correction factors needed to determine
absorbed dose to water or air kerma are published in thepertinent dosimetry protocols. Due to the sole use ofgraphite the energy response of the chamber at energies
below 60Co varies stronger than that of chambers with analuminum electrode. The chamber is designed for the use
in solid state phantoms and therefore not waterproof.

Build-up cap

PMMA, thickness 4.55 mm

Specification

Useful ranges:
Chamber voltage

Graphite wall

Type of productApplication

vented cylindricalionization chamberacc. IEC 60731
absolute therapy dosimetry insolid state phantoms and air

Ion collection efficiency at nominal voltage:
Ion collection time
140 µsMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

5 Gy/s
10 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.46 mGy
0.91 mGy± (100 ... 400) V

Radiation quality

140 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Measuring quantities

absorbed dose to water, airkerma, exposure

Temperature(10 ... 40) °C(50 ... 104) °F

Reference radiation
quality

60Co

Humidity(10 ... 80) %, max 20 g/m3

Nominal sensitive
volume0.6 cm3

Air pressure(700 ... 1060) hPa

Designnot waterproof, vented,
fully guarded

Reference point

on chamber axis, 13 mmfrom chamber tip

Direction of incidence

radialNominal response

20 nC/Gy

Long-term stability≤ 0.5 % per year

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect at 60Co

< 0.5 %

Photon energy response≤ ± 12 % (280 kV ... 60Co)

Directional response insolid state phantom≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 5°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

Ordering Information
TN30011-1 Farmer type chamber 0.6 cm3, C/C,
connecting system BNT
TW30011-1 Farmer type chamber 0.6 cm3, C/C,
connecting system TNC

Options
T48012 Radioactive check device 90Sr
T48002.3.003 Chamber holding device for check device

11Therapy Detectors

Farmer ChamberType 30012
Farmer chamber with graphite wall for
absolute dosimetry in high-energy
photon, electron and proton beams

Features
Fully guarded chamber
Sensitive volume 0.6 cm3, vented to air

Materials and measures:
Wall of sensitive volume0.425 mm graphite,
1.85 g/cm3
Total wall area density

79 mg/cm2

Aluminum central electrode

Dimension of sensitive
volumeradius 3.05 mm
length 23.0 mm

Radioactive check device (option)

Central electrode

Al 99.98, diameter 1.1 mm

Build-up cap

PMMA, thickness 4.55 mm

Graphite wall

The 30012 Farmer chamber is intended for absolutedose measurements in radiation therapy. Correction factors needed to determine absorbed dose to water or air
kerma are published in the pertinent dosimetry protocols. The graphite wall makes the chamber almost waterequivalent, the aluminum central electrode improves theenergy response at energies below 60Co. The chamber isintended for the use in solid state phantoms and therefore not waterproof.

Ion collection efficiency at nominal voltage:
Ion collection time
140 µsMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

5 Gy/s
10 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.46 mGy
0.91 mGy

Specification
Type of productvented cylindricalionization chamberacc. IEC 60731

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

60 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Application

absolute therapy dosimetry insolid state phantoms and air

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.6 cm3

Designnot waterproof, vented,
fully guarded

Ordering Information

Reference point

on chamber axis, 13 mmfrom chamber tip

TN30012-1 Farmer type chamber 0.6 cm3, C/Al,
connecting system BNT

Direction of incidence

radialNominal response

20 nC/Gy

TW30012-1 Farmer type chamber 0.6 cm3, C/Al,
connecting system TNC

Long-term stability≤ 0.5 % per year

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect at 60Co

< 0.5 %

Photon energy response≤ ± 2 % (70 kV ... 280 kV)≤ ± 4 % (200 kV ... 60Co)

Directional response insolid state phantom≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 5°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

12

Options
T48012 Radioactive check device 90Sr
T48002.3.003 Chamber holding device for check device

Therapy Detectors

Farmer ChamberType 30013
Waterproof therapy chamber for
absolute dosimetry in high-energy
photon, electron and proton beams

Features

Acrylic wall, graphited

Materials and measures:
Wall of sensitive volume0.335 mm PMMA,
1.19 g/cm3
0.09 mm graphite,
1.85 g/cm3

Aluminum central electrodeTotal wall area density

56.5 mg/cm2

Radioactive check device (option)

Dimension of sensitive
volumeradius 3.05 mm
length 23.0 mm

Waterproof, fully guarded chamber
Sensitive volume 0.6 cm3, vented to air

The 30013 Farmer chamber is the standard ionizationchamber for absolute dose measurements in radiation
therapy. Correction factors needed to determine
absorbed dose to water or air kerma are published in thepertinent dosimetry protocols. Its waterproof design
allows the chamber to be used in water or in solid state
phantoms. The acrylic chamber wall ensures the ruggedness of the chamber.

Central electrode

Al 99.98, diameter 1.1 mm

Build-up cap

PMMA, thickness 4.55 mm

Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

5 Gy/s
10 Gy/sSpecification

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.46 mGy
0.91 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Type of productvented cylindricalionization chamberacc. IEC 60731

Application

absolute therapy dosimetry
in water, solid state phantoms and air

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.6 cm3

DesignIon collection efficiency at nominal voltage:
Ion collection time
140 µsRadiation quality

30 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

waterproof, vented, fully
guardedAir pressure(700 ... 1060) hPa

Reference point

on chamber axis, 13 mmfrom chamber tip

Ordering Information

Direction of incidence

radialNominal response

20 nC/Gy

TN30013 Farmer type chamber 0.6 cm3, waterproof,
connecting system BNT

Long-term stability≤ 0.5 % per year

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect at 60Co

< 0.5 %

Photon energy response≤ ± 2 % (70 kV ... 280 kV)≤ ± 4 % (200 kV ... 60Co)

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 5°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

TW30013 Farmer type chamber 0.6 cm3, waterproof,
connecting system TNC
TM30013 Farmer type chamber 0.6 cm3, waterproof,
connecting system M

Options
T48012 Radioactive check device 90Sr
T48002.3.003 Chamber holding device for check device

13Therapy Detectors

0.125 cm3 Semiflex
Chamber
Type 31010
Standard therapy chamber forscanning systems and for absolute
dosimetryFeatures

Minimized directional response

Materials and measures:
Wall of sensitive volume0.55 mm PMMA,
1.19 g/cm3
0.15 mm graphite,
0.82 g/cm3

Sensitive volume 0.125 cm3, vented to air

Total wall area density

78 mg/cm2

Radioactive check device (option)

Dimension of sensitive
volumeradius 2.75 mm
length 6.5 mm

Waterproof, semiflexible design for easy mounting inscanning water phantoms

The 31010 semiflexible chamber is the ideal compromise
between small size for reasonable spatial resolution andlarge sensitive volume for precise dose measurements.
This makes the 31010 chamber to one of the most commonly used chambers in scanning water phantom systems. The chamber volume of 0.125 cm3 gives enoughsignal to use the chamber also for high precisionabsolute dose measurements. The sensitive volume isapproximately spherical resulting in a flat angularresponse and a uniform spatial resolution along all threeaxes of a water phantom.

Specification
Type of productvented cylindricalionization chamber

Application

absolute dosimetry inradiotherapy beams

Measuring quantities

Central electrode

Al 99.98, diameter 1.1 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
100 µsMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

6 Gy/s
12 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.5 mGy
1.0 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

absorbed dose to water,
air kerma, exposure

140 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(3 x 3) cm2 ... (40 x 40) cm2

Reference radiation
quality

60Co

Temperature(10 ... 40) °C(50 ... 104) °F

Nominal sensitive
volume0.125 cm3

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 - 1060) hPa

Designwaterproof, vented, fully
guardedReference point

on chamber axis, 4.5 mm
from chamber tip

Direction of incidence

radialNominal response

3.3 nC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect at 60Co

<2%

Options

Photon energy response≤ ± 2 % (140 kV ... 280 kV)≤ ± 4 % (140 kV ... 60Co)

T48012 Radioactive check device 90Sr

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 10°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

14

Ordering Information
TN31010 Semiflex chamber 0.125 cm3,
connecting system BNT
TW31010 Semiflex chamber 0.125 cm3,
connecting system TNC
TM31010 Semiflex chamber 0.125 cm3,
connecting system M

T48002.1.004 Chamber holding device for check device

Therapy Detectors

0.3 cm3 Semiflex
Chamber
Type 31013
Therapy chamber for scanning systems
and for absolute dosimetry

Features
Waterproof, semiflexible design for easy mounting
in scanning water phantoms
Increased sensitive volume for low levelmeasurements
Sensitive volume 0.3 cm3, vented to air
Radioactive check device (option)
The 31013 semiflexible chamber is ideal for precise dose
measurements and for the measurement of dose distributions in scanning water phantom systems. The chamber is used as an alternative for the 31010 chamber incases where increased signal levels are required and spatial resolution along the axis of the chamber can be compromised.

Specification
Type of productvented cylindricalionization chamber

Application

absolute dosimetry inradiotherapy beams

Measuring quantities

absorbed dose to water, airkerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.3 cm3

Designwaterproof, vented, fully
guardedReference point

Materials and measures:
Wall of sensitive volume0.55 mm PMMA,
1.19 g/cm3
0.15 mm graphite,
0.82 g/cm3
Total wall area density

78 mg/cm2

Dimension of sensitive
volumeradius 2.75 mm
length 16.25 mm

Central electrode

Al 99.98, diameter 0.9 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
80 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

14 Gy/s
28 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.8 mGy
1.5 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

100 kV ... 50 MV photons(10 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(4 x 4) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

on chamber axis, 9.5 mm
from chamber tip

Air pressure(700 ... 1060) hPa

Direction of incidence

radialOrdering Information

Nominal response

10 nC/Gy

Long-term stability≤ 1 % per year

TN31013 Semiflex chamber 0.3 cm3,
connecting system BNT

Chamber voltage

400 V nominal± 500 V maximal

TW31013 Semiflex chamber 0.3 cm3,
connecting system TNC

Polarity effect at 60Co

<1%

Photon energy response≤ ± 2 % (140 kV ... 280 kV)≤ ± 4 % (100 kV ... 60Co)

TM31013 Semiflex chamber 0.3 cm3,
connecting system M

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis
and for tilting of the axis
up to ± 10°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

Options
T48012 Radioactive check device 90Sr
T48002.1.004 Chamber holding device for check device

15

Therapy Detectors

0.3 cm3 Rigid Stem
Chamber
Type 30016
Therapy chamber for absolute
dosimetry in high-energy photon andelectron beams

Features

Acrylic wall, graphited

Materials and measures:
Wall of sensitive volume0.35 mm PMMA,
1.19 g/cm3
0.135 mm graphite,
1.85 g/cm3

Aluminum central electrodeTotal wall area density

67 mg/cm2

Radioactive check device (option)

Dimension of sensitive
volumeradius 2.5 mm
length 18 mm

Fully guarded chamber
Sensitive volume 0.3 cm3, vented to air

The 30016 chamber is used for absolute dose measurements in radiation therapy in cases where the high volume of the 30015 chamber is not needed and a higher
spatial resolution is needed. Correction factors needed todetermine absorbed dose to water or air kerma are published in the pertinent dosimetry protocols. The acrylicchamber wall ensures the ruggedness of the chamber.
The chamber is designed for the use in solid state phantoms and is therefore not waterproof.

Specification
Type of productvented cylindricalionization chamber

Application

absolute dosimetry inradiotherapy beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.3 cm3

DesignCentral electrode

Al 99.98, diameter 0.85 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
84 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

11.5 Gy/s
23.1 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.69 mGy
1.38 mGy

Useful ranges:
Chamber voltage± (100 ... 600) V

Radiation quality

70 kV ... 50 MV photons(6 ... 25) MeV electrons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(20 ... 80) %, max 20 g/m3

not waterproof, vented,
fully guarded

Air pressure(700 ... 1060) hPa

Reference point

on chamber axis, 9.5 mm
from chamber tip

Ordering Information

Direction of incidence

radialNominal response

10.5 nC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

400 V nominal± 600 V maximal

Polarity effect≤1%

Photon energy response≤ ± 2 % (70 kV ... 250 kV)≤ ± 4 % (200 kV ... 60Co)

Directional response insolid state phantom≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting of theaxis up to ± 20°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

16

TN30016 Rigid stem chamber 0.3 cm3,
connecting system BNT
TW30016 Rigid stem chamber 0.3 cm3,
connecting system TNC
TM30016 Rigid stem chamber 0.3 cm3,
connecting system M

Options
T48012 Radioactive check device 90Sr
T48002.3.004 Chamber holding device for check device

Therapy Detectors

1.0 cm3 Rigid Stem
Chamber
Type 30015
High-volume therapy chamber for
absolute dosimetry in high-energy
photon and electron beams

Acrylic wall, graphited

Materials and measures:
Wall of sensitive volume
0.4 mm PMMA,
1.19 g/cm3
0.135 mm graphite,
1.85 g/cm3

Aluminum central electrodeTotal wall area density

73 mg/cm2

Radioactive check device (option)

Dimension of sensitive
volumeradius 3.95 mm
length 22 mm

Features
Fully guarded chamber
Sensitive volume 1.0 cm3, vented to air

The 30015 rigid stem chamber is used for absolute dose
measurements in radiation therapy. Correction factors
needed to determine absorbed dose to water or air
kerma are published in the pertinent dosimetry protocols. The acrylic chamber wall ensures the ruggedness ofthe chamber. The chamber is designed for the use insolid state phantoms and is therefore not waterproof.

Specification
Type of productvented cylindricalionization chamber

Application

absolute dosimetry inradiotherapy beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume1.0 cm3

Designnot waterproof , vented,
fully guarded

Reference point

Central electrode

Al 99.98, diameter 1.1 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
236 µsMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

1.5 Gy/s
2.9 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.25 mGy
0.49 mGy

Useful ranges:
Chamber voltage± (100 ... 600) V

Radiation quality

70 kV ... 50 MV photons(10 ... 45) MeV electrons

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(20 ... 80) %, max 20 g/m3

on chamber axis, 11.5 mm
from chamber tip

Air pressure(700 ... 1060) hPa

Direction of incidence

radialOrdering Information

Nominal response

31.9 nC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

400 V nominal± 600 V maximal

Polarity effect≤1%

Photon energy response≤ ± 2 % (70 kV ... 250 kV)≤ ± 4 % (200 kV ... 60Co)

TN30015 Rigid stem chamber 1.0 cm3,
connecting system BNT
TW30015 Rigid stem chamber 1.0 cm3,
connecting system TNC
TM30015 Rigid stem chamber 1.0 cm3,
connecting system M

Directional response insolid state phantom≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting of theaxis up to ± 20°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

Options
T48012 Radioactive check device 90Sr
T48002.3.004 Chamber holding device for check device

17Therapy Detectors

Advanced Markus
Chamber
Type 34045
Perturbation-free version of the famousclassic Markus chamber for absolute
dosimetry in high-energy electron beams

Features
Perturbation-free electron chamberThin entrance window and waterproof
protection cap
Small-sized for high spatial resolution
Sensitive volume 0.02 cm3, vented to air
Radioactive check device (option)
The 34045 Advanced Markus chamber is the successorof the well-known classic Markus electron chamber,equipped with a wide guard ring for perturbation-freemeasurements. The thin entrance window allows measurements in solid state phantoms up to the surface. The
protection cap makes the chamber waterproof for measurements in water phantoms.

Specification
Type of productvented plane parallel
ionization chamber

Application

absolute dosimetry in highenergy electron beams

Measuring quantity

absorbed dose to water

Reference radiation
quality

60Co

Nominal sensitive
volume0.02 cm3

Designwaterproof with protection
cap, vented

Reference pointin chamber center on
entrance foil, or 1.3 mm
below surface ofprotection cap

Direction of incidence

perpendicular to chamber
plane

Nominal response

0.67 nC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

300 V nominal± 400 V maximal

Polarity effect≤1%for electrons ≥ 9 MeV

Directional response inwater≤ ± 0.1 % for chamber
tilting ≤ ± 10°

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

18

Materials and measures:
Entrance foil
0.03 mm PE (polyethylene
CH2), 2.76 mg/cm2
Protection cap

0.87 mm PMMA,
1.19 g/cm3, 0.4 mm air

Total window area density 106 mg/cm2, 1.3 mm(protection cap included)
Water-equivalent window
thickness

1.06 mm(protection cap included)

Sensitive volume

radius 2.5 mm
depth 1 mm

Guard ring width

2 mm

Ion collection efficiency at nominal voltage:
Ion collection time
22 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

187 Gy/s
375 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

2.78 mGy
5.56 mGy

Useful ranges:
Chamber voltage± (50 ... 300) V

Radiation quality(2 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(3 x 3) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering Information
TN34045 Advanced Markus electron chamber,
0.02 cm3, connecting system BNT
TW34045 Advanced Markus electron chamber,
0.02 cm3, connecting system TNC
TM34045 Advanced Markus electron chamber,
0.02 cm3, connecting system M

Options
T48010 Radioactive check device 90Sr
T23343/11 Chamber holding device for check device

Therapy Detectors

Markus ChamberType 23343
Classic plane parallel chamber for
absolute dosimetry in high-energy
electron beams

FeaturesThin entrance window and waterproof
protection cap
Small-sized for high spatial resolution
Sensitive volume 0.055 cm3, vented to air
Radioactive check device (option)
The 23343 Markus chamber is manufactured in the original famous Markus design. Absorbed dose to water canbe measured by applying correction factors for perturbation effects as published in pertinent dosimetry protocols. The thin entrance window allows measurements insolid state phantoms up to the surface. The protection
cap makes the chamber waterproof for measurements inwater phantoms.

Specification
Type of productvented plane parallel
ionization chamber

Application

absolute dosimetry in highenergy electron beams

Measuring quantity

absorbed dose to water

Reference radiation quality 60Co

Materials and measures:
Entrance foil
0.03 mm PE (polyethylene
CH2), 2.76 mg/cm2
Protection cap

0.87 mm PMMA,
1.19 g/cm3, 0.4 mm air

Total window area density 106 mg/cm2, 1.3 mm(protection cap included)
Water-equivalent window
thickness

1.06 mm(protection cap included)

Sensitive volume

radius 2.65 mm
depth 2 mm

Guard ring width< 0.2 mmIon collection efficiency at nominal voltage:
Ion collection time
90 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

12 Gy/s
24 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.7 mGy
1.4 mGy

Useful ranges:
Chamber voltage± (100 ... 300) V

Nominal sensitive volume0.055 cm3

Radiation quality

Designwaterproof with protection
cap, vented(2 ... 45) MeV electrons(50 ... 270) MeV protons

Field size

(3 x 3) cm2 ... (40 x 40) cm2

Reference pointin chamber center on
entrance foil, or 1.3 mm
below surface ofprotection cap

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Direction of incidence

perpendicular to chamber
plane

Air pressure(700 ... 1060) hPa

Nominal response

2 nC/Gy

Ordering Information

Long-term stability≤ 1 % per year

Chamber voltage

300 V nominal± 400 V maximal

Polarity effect≤1%for electrons ≥ 9 MeV

Directional response inwater≤ ± 0.1 % for chamber
tilting ≤ ± 10°TN23343 Markus electron chamber 0.055 cm3,
connecting system BNT
TW23343 Markus electron chamber 0.055 cm3,
connecting system TNC
TM23343 Markus electron chamber 0.055 cm3,
connecting system M

Leakage current≤ ± 4 fA

Options

Cable leakage≤ 3.5 pC/(Gy·cm)

T48010 Radioactive check device 90Sr
T23343/11 Chamber holding device for check device

19Therapy Detectors

Roos ChamberType 34001
Waterproof plane parallel chamber for
absolute dosimetry in high-energy
electron and proton beams

Features
Perturbation-free, minimized polarity effect
Waterproof, wide guard ring design
Sensitive volume 0.35 cm3, vented to air
Radioactive check device (option)
The 34001 Roos chamber is the golden standard for
absolute dose measurements in high-energy electron
beams. Modern dosimetry protocols refer to the chamber's design and provide dosimetric correction factors. Its
waterproof design allows the chamber to be used inwater or in solid state phantoms. The Roos chamber isalso well suited for the measurement of high-energy
photon depth dose curves up to 2.5 mm below thewater surface. The chamber can be used for dose measurements of proton beams.

Specification

Materials and measures:
Entrance window
1 mm PMMA, 1.19 g/cm3
0.02 mm graphite,
0.82 g/cm3
0.1 mm varnish,
1.19 g/cm3
Total window area density 132 mg/cm2
Water-equivalent window
thickness

1.3 mmSensitive volume

radius 7.5 mm
depth 2 mm

Guard ring width

4 mm

Ion collection efficiency at nominal voltage:
Ion collection time
125 µsMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

5.2 Gy/s
10.4 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.46 mGy
0.93 mGy± (50 ... 300) V

Type of productvented plane parallel
ionization chamberacc. IEC 60731

Application

absolute dosimetry inhigh-energy electron andproton beams

Useful ranges:
Chamber voltage

Measuring quantity

absorbed dose to water

Radiation quality

Reference radiation
quality

60Co

Nominal sensitive
volume0.35 cm3

Designwaterproof, vented

Reference pointin chamber center,1.12 mm below surface

Direction of incidence

perpendicular to chamber
plane, see label 'Focus'(2 ... 45) MeV electrons

60Co ... 25 MV photons(50 ... 270) MeV protons
Field size

(4 x 4) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering Information

Nominal response

12 nC/Gy

Long-term stability≤ 0.5 % per year

TN34001 Roos electron chamber 0.35 cm3,
connecting system BNT

Chamber voltage

200 V nominal± 400 V maximal

TW34001 Roos electron chamber 0.35 cm3,
connecting system TNC

Polarity effect< 0.5 %

Directional response inwater≤ ± 0.1 % for chamber
tilting ≤ ± 10°

TM34001 Roos electron chamber 0.35 cm3,
connecting system M

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

20

Options
T48010 Radioactive check device 90Sr
T48004 Chamber holding device for check device

Therapy Detectors

Bragg Peak ChamberType 34070

Waterproof plane-parallel chamber for
dosimetry in proton beams

Features
Waterproof, wide guard ring design
Sensitive volume 10.5 cm3, vented to air
The 34070 Bragg peak chamber is designed to measure
the exact location of the Bragg peak in therapy proton
beams. The large diameter of the chamber allows
the measurement of the complete proton beam diameter (non-scanned) including the scattered protons.
The chamber is waterproof and consequently can either
be used in air behind a water column or in a water
phantom.
In water, the Bragg Peak chamber can be used for measurements of horizontal beams. Due to the thickness ofthe entrance and exit windows, the chamber can additionally be used in vertical beams where measurements
are performed in different water depths.

Specification

Materials and measures:
Entrance window
3.35 mm PMMA
0.02 mm graphite
0.1 mm varnish
Total window area density 411 mg/cm2
Water-equivalent window
thickness

4 mm

Sensitive volume

radius 40.8 mm,
depth 2 mm

Guard ring width

1.1 mm

Ion collection efficiency at nominal voltage:
Ion collection time
67 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

21 Gy/s
42 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.9 mGy
1.8 mGy

Useful ranges:
Chamber voltage(300 ... 500) V

Radiation quality(70 ... 250) MeV protons

Field size

diameter (3 ... 10) mm

Type of productvented plane parallel
ionization chamber

Application

relative dosimetry in highenergy proton beams

Nominal sensitive
volume10.5 cm3

Designwaterproof, vented

Temperature(10 ... 40) °C(50 ... 104) °F

Reference pointin chamber center,3.47 mm from chamber
surface

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Direction of incidence

perpendicular to chamber
plane, see label 'Focus'

Nominal response

325 nC/Gy(at 60Co free in air)

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect≤1%

Leakage current≤ ± 100 fA

Cable leakage≤ 1 pC/(Gy·cm)

Cable length

2.5 m

Ordering Information
TN34070-2,5 Bragg peak chamber 10.5 cm3,
connecting system BNT
TW34070-2,5 Bragg peak chamber 10.5 cm3,
connecting system TNC
TM34070-2,5 Bragg peak chamber 10.5 cm3,
connecting system M

21

Therapy Detectors

Bragg Peak ChamberType 34073

Waterproof plane-parallel chamber for
dosimetry in proton beams

Features
Waterproof, wide guard ring design
Sensitive volume 2.5 cm3, vented to air
The 34073 Bragg peak chamber is designed to measure
the exact location of the Bragg peak in therapy proton
beams. The large diameter of the chamber allows
the measurement of the complete proton beam diameter (non-scanned) including the scattered protons.
The chamber is waterproof and consequently can either
be used in air behind a water column or in a water
phantom.
In water, the Bragg Peak chamber can be used for measurements of horizontal beams.

Specification

Materials and measures:
Entrance window
1.01 mm PMMA
0.02 mm graphite
0.1 mm varnish
Total window area density 133 mg/cm2
Water-equivalent window
thickness

1.3 mmSensitive volume

radius 19.8 mm
depth 2 mm

Guard ring width

4 mm

Ion collection efficiency at nominal voltage:
Ion collection time
67 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

21 Gy/s
42 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.9 mGy
1.8 mGy

Useful ranges:
Chamber voltage(300 ... 500) V

Type of productvented plane parallel
ionization chamber

Application

relative dosimetry in highenergy proton beams

Nominal sensitive
volume2.5 cm3

Designwaterproof, vented

Radiation quality(70 ... 250) MeV protons

Reference pointin chamber center,1.13 mm from chamber
surface

Field size

diameter (3 ... 10) mm

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3
(700 ... 1060) hPa

Direction of incidence

perpendicular to chamber
plane, see label 'Focus'

Nominal response

78 nC/Gy(at 60Co free in air)

Air pressure

Chamber voltage

400 V nominal± 500 V maximal

Ordering Information

Polarity effect≤1%

Leakage current≤ ± 100 fA

Cable leakage≤ 1 pC/(Gy·cm)

Cable length

2.5 m

22

TN34073-2,5 Bragg peak chamber 2.5 cm3,
connecting system BNT
TW34073-2,5 Bragg peak chamber 2.5 cm3,
connecting system TNC
TM34073-2,5 Bragg peak chamber 2.5 cm3,
connecting system M

Therapy Detectors

PinPoint ChamberType 31014
Ultra small-sized therapy chamber for
dosimetry in high-energy photon
beams

Features
Small-sized sensitive volumes of only 0.015 cm3 and2 mm in diameter, vented to air
Very high spatial resolution when used for scansperpendicular to the chamber axis
Aluminum central electrode
Radioactive check device (option)
The 31014 PinPoint chamber is ideal for dose measurements in small fields as encountered e.g. in IORT, IMRT
and stereotactic beams. Relative dose distributions canbe measured with very high spatial resolution when thechamber is moved perpendicular to the chamber axis.
The waterproof, fully guarded chamber can be used inair, solid state phantoms and in water.

Materials and measures:
Wall of sensitive volume
0.57 mm PMMA,
1.19 g/cm3
0.09 mm graphite,
1.85 g/cm3
Total wall area density

85 mg/cm2

Dimensions of sensitive
volumeradius 1 mm
length 5 mm

Central electrode

Al 99.98, diameter 0.3 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
20 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

265 Gy/s
580 Gy/s
3.5 mGy
7 mGy

Type of productvented cylindricalionization chamberMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

Application

dosimetry in high-energy
photon beams with highspatial resolution

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

60Co ... 50 MV photons

Field size

(2 x 2) cm2 ... (30 x 30) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3
(700 ... 1060) hPa

Specification

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.015 cm3

Designwaterproof, vented, fully
guardedAir pressure

Reference point

on chamber axis, 3.4 mm
from chamber tip

Ordering Information

Direction of incidence

radial, axial

Pre-irradiation dose

2 Gy

Nominal response

400 pC/Gy

Long-term stability≤ 1 % per year

TN31014 PinPoint chamber 0.015 cm3,
connecting system BNT
TW31014 PinPoint chamber 0.015 cm3,
connecting system TNC
TM31014 PinPoint chamber 0.015 cm3,
connecting system M

Chamber voltage

400 V nominal± 500 V maximal

Options

Polarity effect≤±2%

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting of theaxis up to± 20° (radial incidence)± 15° (axial incidence)

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

T48012 Radioactive check device 90Sr
T48002.1.007 Chamber holding device for check device

23Therapy Detectors

PinPoint ChamberType 31015
Small-sized therapy chamber for
dosimetry in high-energy photon
beams

Features
Small-sized sensitive volume of only 0.03 cm3 and2.9 mm in diameter, vented to air
Very high spatial resolution when used for scansperpendicular to the chamber axis
Aluminum central electrode
Radioactive check device (option)
The 31015 PinPoint chamber is ideal for dose measurements in small fields as encountered e.g. in IORT, IMRT
and stereotactic beams. Relative dose distributions canbe measured with very high spatial resolution when thechamber is moved perpendicular to the chamber axis.
The waterproof, fully guarded chamber can be used inair, solid state phantoms and in water.

Materials and measures:
Wall of sensitive volume
0.57 mm PMMA,
1.19 g/cm3
0.09 mm graphite,
1.85 g/cm3
Total wall area density

85 mg/cm2

Dimensions of sensitive
volumeradius 1.45 mm
length 5 mm

Central electrode

Al 99.98, diameter 0.3 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
50 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

29 Gy/s
55 Gy/s
1.2 mGy
2.3 mGy

Type of productvented cylindricalionization chamberMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

Application

dosimetry in high-energy
photon beams with highspatial resolution

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

60Co ... 50 MV photons

Field size

(2 x 2) cm2 ... (30 x 30) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3
(700 ... 1060) hPa

Specification

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.03 cm3

Designwaterproof, vented, fully
guardedAir pressure

Reference point

on chamber axis, 3.4 mm
from chamber tip

Ordering Information

Direction of incidence

radialPre-irradiation dose

2 Gy

Nominal response

800 pC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

400 V nominal± 500 V maximal

Polarity effect≤±2%

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting of theaxis up to± 20° (radial incidence)± 15° (axial incidence)

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

24

TN31015 PinPoint chamber 0.03 cm3,
connecting system BNT
TW31015 PinPoint chamber 0.03 cm3,
connecting system TNC
TM31015 PinPoint chamber 0.03 cm3,
connecting system M

Options
T48012 Radioactive check device 90Sr
T48002.1.007 Chamber holding device for check device

Therapy Detectors

PinPoint 3D ChamberType 31016
Ultra small-sized therapy chamber with
3D characteristics for dosimetry inhigh-energy photon beams

Features

Aluminum central electrode

Materials and measures:
Wall of sensitive
0.57 mm PMMA,
volume1.19 g/cm3
0.09 mm graphite,
1.85 g/cm3

Radioactive check device (option)

Total wall area density

85 mg/cm2

Dimensions of sensitive
volumeradius 1.45 mm
length 2.9 mm

Small-sized sensitive volume 0.016 cm3, vented to air
Minimized directional response

The 31016 PinPoint 3D chamber is ideal for dose measurements in small fields as encountered e.g. in IORT,IMRT and stereotactic beams. Relative dose distributions
can be measured with high spatial resolution in any
direction. The waterproof, fully guarded chamber can beused in air, solid state phantoms and in water.

Specification

Central electrode

Al 99.98, diameter 0.3 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
60 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

19 Gy/s
38 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

1.0 mGy
1.9 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality

60Co ... 50 MV photons

Field size

(2 x 2) cm2 … (30 x 30) cm2

waterproof, vented, fully
guardedTemperature(10 ... 40) °C(50 ... 104) °F

Reference point

on chamber axis, 2.4 mm
from chamber tip

Humidity(10 ... 80) %, max 20 g/m3

Direction of incidence

radialAir pressure(700 ... 1060) hPa

Type of productvented cylindricalionization chamber

Application

dosimetry in high-energy
photon beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

60Co

Nominal sensitive
volume0.016 cm3

DesignPre-irradiation dose

2 Gy

Nominal response

400 pC/Gy

Long-term stability≤ 1 % per year

TN31016 PinPoint 3D chamber 0.016 cm3,
connecting system BNT

Chamber voltage

400 V nominal± 500 V maximal

TW31016 PinPoint 3D chamber 0.016 cm3,
connecting system TNC

Polarity effect≤±2%

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting of theaxis up to ± 110°

TM31016 PinPoint 3D chamber 0.016 cm3,
connecting system M

Leakage current≤ ± 4 fA

Cable leakage≤ 1 pC/(Gy·cm)

Ordering Information

Options
T48012 Radioactive check device 90Sr
T48002.1.008 Chamber holding device for check device

25Therapy Detectors

microDiamondType 60019
Diamond Detector for dosimetry inhigh-energy photon and electron beams,
especially useful for small field dosimetry

Features
Small sensitive volume of 0.004 mm3
Excellent radiation hardness and temperature
independence
Near tissue-equivalence
Operates without high voltage
All connecting systems available (BNT, TNC, M)
The new microDiamond detector is a synthetic single
crystal diamond detector (SCDD), based on a uniquefabrication process [1, 2]. Significant advantages of thesynthetic production are standardised assembly andconsequently a high reproducibility of the dosimetricproperties and good availability of the detector.

Materials and measures:
Entrance window
0.3 mm RW3
0.6 mm Epoxy
0.01 mm Al 99.5
Total window
area density

101 mg/cm2

Water-equivalent
window thickness

1.0 mmSensitive volume

radius 1.1 mm, circular,
thickness 1 µm

Outer dimensions

diameter 7 mm,
length 45.5 mm

Useful ranges:
Radiation quality

Specification

100 keV ... 25 MV photons(6 ... 25) MeV electrons

Type of productsynthetic single crystal
diamond detector

Field size2(1 x 1) cm2 ... (40 x 40) cm2

Application

dosimetry in radiotherapy
beams

Temperature(10 ... 35) °C, (50 ... 95) °F

Humidity range(10 ... 80) %, max 20 g/m3

Measuring
quantitiyabsorbed dose to water

Reference
radiation quality

60Co

Nominal sensitive
volume0.004 mm3

TN60019 microDiamond Detector, connecting system BNT
TW60019 microDiamond Detector, connecting system TNC
TM60019 microDiamond Detector, connecting system M

Designwaterproof, disk-shaped,
sensitive volume perpendicular to detector axis

The microDiamond detector is realized in collaboration with Marco
Marinelli and Gianluca Verona-Rinati and their team, Industrial
Engineering Department of Rome Tor Vergata University, Italy.

Reference point

on detector axis, 1 mm fromdetector tip, marked by ring

Direction ofincidence

axial

Pre-irradiation dose

5 Gy

Nominal response

1 nC/Gy

Ordering Information

Long-term stability≤ 0.5 % per year

Dose stability< 0.25 % / kGy at 18 MV

Temperature
response≤ 0.08 % / K

Energy response± 8 % (100 keV ... 60Co)

Bias voltage

0V

Signal polarity

positive

Directional
response in water≤ 1 % for tilting ≤ ± 40°

Leakage current1≤ 20 fA

Cable leakage≤ 200 fC / (Gy·cm)

26[1] I. Ciancaglioni, M. Marinelli, E. Milani, G. Prestopino, C. Verona,
G. Verona-Rinati, R. Consorti, A. Petrucci and F. De Notaristefani,
Dosimetric characterization of a synthetic single crystal diamonddetector in clinical radiation therapy small photon beams,
Med. Phys. 39 (2012), 4493
[2] C. Di Venanzio, M. Marinelli, E. Milani, G. Prestopino, C. Verona,
G. Verona-Rinati, M. D. Falco, P. Bagalà, R. Santoni and M. Pimpinella,
Characterization of a synthetic single crystal diamond Schottky diodefor radiotherapy electron beam dosimetry, Med. Phys. 40 (2013),
021712

1 At the high end of the temperature range, higher leakage currents may
occur.
2 This detector is well suited for measurements in field sizes smaller than
1 cm x 1 cm. Depending on the accuracy required by the user, correction
factors may be necessary as described in international scientific publications. This applies to any detector used in very small fields.

Therapy Detectors

Dosimetry Diode P
Type 60016
Waterproof silicon detector for
dosimetry in high-energy photon
beams up to field size 40 cm x 40 cm

Features
Useful for measurements in small and large photon
fieldsExcellent spatial resolution
Minimized energy response for field size independentmeasurements up to 40 cm x 40 cm
The 60016 Dosimetry Diode P is ideal for dose measurements in small photon fields as encountered in IORT, IMRT
and stereotactic beams. The excellent spatial resolution
makes it possible to measure very precisely beam profiles
even in the penumbra region of small fields. The superiorenergy response enables the user to perform accurate
percentage depth dose measurements which are field size
independent up to field sizes of (40 x 40) cm2. The waterproof detector can be used in air, solid state phantoms andin water.

Specification

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting ≤ ± 40°

Leakage current≤ ± 50 fA

Cable leakage≤ 1 pC/(Gy·cm)

Materials and measures:
Entrance window
1 mm RW3,
1.045 g/cm3
1 mm epoxy
Total window area density 250 mg/cm2
Water-equivalent window
thickness

2.42 mm

Sensitive volume

1 mm2 circular
30 µm thickOuter dimensions

diameter 7 mm,
length 47 mm

Useful ranges:
Radiation quality

60Co ... 25 MV photons

Field size

(1 x 1) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Type of productp-type silicon diodeApplication

dosimetry in radiotherapy
beams

Measuring quantity

absorbed dose to water

Reference radiation
quality

60Co

Nominal sensitive
volume0.03 mm3

Ordering Information

Designwaterproof, disk-shaped
sensitive volume perpendicular to detector axis

TN60016 Dosimetry Diode P, connecting system BNT
TW60016 Dosimetry Diode P, connecting system TNC
TM60016 Dosimetry Diode P, connecting system M

Reference point

on detector axis, 2.42 mm
from detector tip

Direction of incidence

axial

Nominal response

9 nC/Gy

Dose stability≤ 0.5 %/kGy at 6 MV
≤ 1 %/kGy at 15 MV≤ 0.5 %/kGy at 5 MeV≤ 4 %/kGy at 21 MeV

Temperature response≤ 0.4 %/K

Energy response

at higher depths than dmax,
the percentage depth dose
curves match curves measured with ionization chambers within ± 0.5 %Bias voltage

0V

Signal polarity

negative

27

Therapy Detectors

Dosimetry Diode E
Type 60017
Waterproof silicon detector for
dosimetry in high-energy electron
and photon beams

Features
Useful for measurements in all electron fields and forsmall photon fields
Excellent spatial resolution
Minimized energy response
Thin entrance window for measurements in thevicinity of surfaces and interfaces
The 60017 Dosimetry Diode E is ideal for dose measurements in small electron and photon fields as encountered in IORT, IMRT and stereotactic beams. The excellent
spatial resolution makes it possible to measure very
precisely beam profiles even in the penumbra region ofsmall fields. The Dosimetry Diode E is recommended for
dose measurements in all electron fields and for photon
fields up to (10 x 10) cm2. The waterproof detector canbe used in air, solid state phantoms and in water.

Directional response inwater≤ ± 0.5 % for rotation
around the chamber axis,≤ ± 1 % for tilting ≤ ± 20°

Leakage current≤ ± 50 fA

Cable leakage≤ 1 pC/(Gy·cm)

Materials and measures:
Entrance window
0.3 mm RW3,
1.045 g/cm3
0.4 mm epoxy
Total window area density 140 mg/cm2
Water-equivalent window
thickness

1.33 mm

Sensitive volume

1 mm2 circular
30 µm thickOuter dimensions

diameter 7 mm,
length 45.5 mm

Type of productp-type silicon diodeUseful ranges:
Radiation quality

Application

dosimetry in radiotherapy
beams

Field size 1

Measuring quantity

absorbed dose to water

Reference radiation
quality

60Co(1 x 1) cm2 ... (40 x 40) cm2
for electrons(1 x 1) cm2 ... (10 x 10) cm2
for photons

Temperature

Nominal sensitive
volume0.03 mm3(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Designwaterproof, disk-shaped
sensitive volume perpendicular to detector axis

Specification

Reference point

on detector axis, 1.33 mmfrom detector tip

Direction of incidence

axial

Nominal response

9 nC/Gy

Dose stability≤ 0.5 %/kGy at 6 MV
≤ 1 %/kGy at 15 MV≤ 0.5 %/kGy at 5 MeV≤ 4 %/kGy at 21 MeV

Temperature response≤ 0.4 %/K

Energy response

at higher depths than dmax,
the percentage depth dose
curves match curves measured with ionization chambers within ± 0.5 %Bias voltage

0V

Signal polarity

negative

28(6 ... 25) MeV electrons
60Co ... 25 MV photons

Ordering Information
TN60017 Dosimetry Diode E, connecting system BNT
TW60017 Dosimetry Diode E, connecting system TNC
TM60017 Dosimetry Diode E, connecting system M
1 This detector is well suited for measurements in field sizes smaller than
1 cm x 1 cm. Depending on the accuracy required by the user, correction
factors may be necessary as described in international scientific publications. This applies to any detector used in very small fields.

Therapy Detectors

Dosimetry Diode SRS
Type 60018
Waterproof silicon detector for
dosimetry in 6 MV photon beams up
to field size 10 cm x 10 cm

Features
Designed for measurements in small photon fields
with maximum 6 MV
Excellent spatial resolution

Materials and measures:
Entrance window
0.3 mm RW3,
0.27 mm epoxy
Total window area density 140 mg/cm2
Water-equivalent window

High response

1.31 mmthickness

Very low noise

Sensitive volume

Thin entrance window for measurements in thevicinity of surfaces and interfaces

1 mm2 circular
250 µm thickOuter dimensions

diameter 7 mm,
length 45.5 mm

The 60018 Dosimetry Diode SRS is ideal for dose measurements in photon fields with a maximum field sizeof 10 cm x 10 cm and with a maximum energy of 6 MV.
The very high response of this detector allows to measure beam profiles with a very high resolution and very
short dwell time. Typical use is beam profile measurement for stereotactic radio surgery (SRS).

Useful ranges:
Radiation quality

60Co ... 6 MV photons

Field size 1(1 x 1) cm2 ... (10 x 10) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Specification
Type of productp-type silicon diodeApplication

dosimetry in radiotherapy
beams

Measuring quantity

absorbed dose to water

Reference radiation

60Co

Ordering Information
TN60018 Dosimetry Diode SRS, connecting system BNT
TW60018 Dosimetry Diode SRS, connecting system TNC
TM60018 Dosimetry Diode SRS, connecting system M

qualityNominal sensitive

0.3 mm3

volumeDesignwaterproof, disk-shaped
sensitive volume perpendicular to detector axis

Reference point

on detector axis, 1.31 mmfrom detector tip

Direction of incidence

axial

Nominal response

175 nC/Gy

Dose stability≤ 0.8 %/kGy at 6 MV

Temperature response≤ (0.1 ± 0.05) %/K

Energy response

at higher depths than dmax,
the percentage depth dose
curves match curves measured with ionization chambers within ± 0.5 %Bias voltage

0V

Signal polarity

negative

Directional response in≤ ± 0.5 % for rotationwater

around the chamber axis,≤ ± 1 % for tilting ≤ ± 20°

Leakage current≤ ± 50 fA

Cable leakage≤ 1 pC/(Gy·cm)

1 This detector is well suited for measurements in field sizes smaller than
1 cm x 1 cm. Depending on the accuracy required by the user, correction
factors may be necessary as described in international scientific publications. This applies to any detector used in very small fields.

29

Therapy Detectors

Dosimetry Diode PR
Type 60020

Waterproof silicon detector for
dosimetry in high-energy proton beams

Features
Useful for measurements in proton fields
Excellent spatial resolution
Thin entrance window for measurements in thevicinity of surfaces and interfaces
The 60020 Dosimetry Diode PR is ideal for dose
measurements in proton beams. The excellent spatial
resolution makes it possible to measure very precisely
beam profiles even in the penumbra region of small
fields The waterproof detector can be used in air, solidstate phantoms and in water. The detector shows anincreased dose stability compared with other silicon
diode detectors.

Specification

Materials and measures:
Entrance window
0.3 mm RW3
0.4 mm epoxy
Total window
area density

140 mg/cm2

Water-equivalent
window thickness

1.33 mm

Sensitive volume

1 mm2 circular
20 µm thickOuter dimensions

diameter 7 mm,
length 45.5 mm

Useful ranges:
Radiation quality(50 … 270) MeV protons

Field Size1(1 x 1) cm2... (40 x 40) cm2

Temperature(10 … 40) °C(50 … 104) °F(10 … 80) %, max 20 g/m3

Type of productp-type silicon diodeApplication

dosimetry in radiotherapy

Measuring
quantity

absorbed dose to water

Humidity

Reference
radiation quality

60Co

Ordering Information

Nominal sensitive
volume0.02 mm3

Designwaterproof, disk-shaped
sensitive volume perpendicular to detector axis

Reference point

on detector axis, 1.33 mmfrom detector tip

Direction ofincidence

axial

Nominal response

6 nC/Gy

Dose stability≤ 9 %/kGy
after initial preirradiation

Temperature
response≤ 0.4 %/K

Bias voltage

0V

Signal polarity

negative

Directional
response≤ ± 0.5 % for rotation
around the chamber axis
≤ ± 1 % when tilting ± 20°

Leakage current≤ ± 50 fA

Cable leakage≤ 1 pC/(Gy·cm)

30

TN60020 Dosimetry Diode PR, connecting system BNT
TW60020 Dosimetry Diode PR, connecting system TNC
TM60020 Dosimetry Diode PR, connecting system M

1 This detector is well suited for measurements in field sizes smaller than
1 cm x 1 cm. Depending on the accuracy required by the user, correction
factors may be necessary as described in international scientific publications. This applies to any detector used in very small fields.

Therapy Detectors

0.02 cm3 Soft X-Ray
Chamber
Type 23342
Thin window plane parallel chamber
for dose measurements in superficial
radiation therapy

Ultra thin entrance window

Materials and measures:
Entrance foil
0.03 mm PE

For low-energy photons from 8 keV to 35 keV

Total window area density 2.76 mg/cm2

Sensitive volume 0.02 cm3, vented to air

Sensitive volume

Features

Radioactive check device (option)
The 23342 soft X-ray chamber is the golden standard for
absolute dose measurements in low-energy photon
beams as used in superficial radiation therapy. Correction
factors needed for the determination of absorbed doseto water are available. The chamber is designed for theuse in solid state phantoms.

Specification

radius 1.5 mm
depth 1 mm

Ion collection efficiency at nominal voltage:
Ion collection time
30 µs
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

175 Gy/s
350 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

1.8 mGy
4.5 mGy

Type of productvented plane parallel
ionization chamberacc. IEC 60731

Useful ranges:
Chamber voltage± (100 ... 400) V

Application

absolute dosimetry in
low-energy photon beams

Radiation quality(8 ... 35) keV X-rays

Measuring quantities

absorbed dose to water,
air kerma, exposure

Field size

(1 x 1) cm2 ... (40 x 40) cm2

Temperature

Reference radiation
quality

30 kV, HVL 0.37 mm Al (T30)(10 ... 40) °C(50 ... 104) °F

Humidity(20 ... 80) %, max 20 g/m3

Nominal sensitive
volume0.02 cm3

Air pressure(700 ... 1060) hPa

Designnot waterproof, vented

Ordering Information

Reference pointin chamber center ofentrance foil underside

TN23342 Soft X-ray chamber 0.02 cm3,
connecting system BNT

Direction of incidence

perpendicular to chamber
plane

Nominal response

1 nC/Gy

TW23342 Soft X-ray chamber 0.02 cm3,
connecting system TNC

Long-term stability≤ 1 % per year

TM23342 Soft X-ray chamber 0.02 cm3,
connecting system M

Chamber voltage

300 V nominal± 500 V maximal

Options

Directional response≤ ± 1 % for chamber tilting
up to ± 20°

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

T48010 Radioactive check device 90Sr
T23238 Chamber holding device for check device

31Therapy Detectors

0.2 cm3 Soft X-Ray
Chamber
Type 23344
Thin window plane parallel chamber
for dose measurements in superficial
radiation therapy

Features
Ultra thin entrance window

Materials and measures:
Entrance foil
0.03 mm PE

For low-energy photons from 8 keV to 35 keV

Total window area density 2.76 mg/cm2

Sensitive volume 0.2 cm3, vented to air

Sensitive volume

Radioactive check device (option)

radius 6.5 mm
depth 1.5 mm

The 23344 soft X-ray chamber is used for absolute dose
measurements in low-energy photon beams as used insuperficial radiation therapy. The sensitive volume islarger than that of the 23342 chamber, giving a higher
signal at the cost of a lower spatial resolution. Correction
factors needed for the determination of absorbed doseto water are available. The chamber is designed for theuse in solid state phantoms.

Ion collection efficiency at nominal voltage:
Ion collection time
30 µs

Specification

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality(8 ... 35) keV X-rays

Field size

(2 x 2) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Type of productvented plane parallel
ionization chamberacc. IEC 60731

Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

60 Gy/s
120 Gy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

1.1 mGy
2.7 mGy

Application

absolute dosimetry in lowenergy photon beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Humidity(20 ... 80) %, max 20 g/m3

Reference radiation
quality

30 kV, HVL 0.37 mm Al (T30)

Air pressure(700 ... 1060) hPa

Nominal sensitive
volume0.2 cm3

Ordering Information

Designnot waterproof, vented

TN23344 Soft X-ray chamber 0.2 cm3,
connecting system BNT

Reference pointin chamber center ofentrance foil underside

Direction of incidence

perpendicular to chamber
plane

Nominal response

7 nC/Gy

Long-term stability≤ 1 % per year

Options

Chamber voltage

400 V nominal± 500 V maximal

T48010 Radioactive check device 90Sr

Directional response≤ ± 1 % for chamber tilting
up to ± 20°

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

32

TW23344 Soft X-ray chamber 0.2 cm3,
connecting system TNC
TM23344 Soft X-ray chamber 0.2 cm3,
connecting system M

T23236 Chamber holding device for check device

Therapy Detectors

0.005 cm3 SoftX-Ray ChamberType 34013
Thin window plane parallel chamber
for dose measurements in superficial
radiation therapy

Features
Ultra thin entrance window

Materials and measures:
Entrance foil
0.03 mm PE

For low-energy photons from 8 keV to 35 keV

Total window area density 2.76 mg/cm2

Extremely small size

Sensitive volume

Sensitive volume 0.005 cm3, vented to air

radius 0.85 mm
depth 0.9 mm

The 34013 soft X-ray chamber is used for absolute dose
measurements in low-energy photon beams as usedin superficial radiation therapy. The chamber’s small
size enables the user to perform measurements withexcellent spatial resolution. Correction factors needed
for the determination of absorbed dose to water areavailable. The chamber is designed for the use in solidstate phantoms.

Ion collection efficiency at nominal voltage:
Ion collection time
0.03 ms

Specification

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality(8 ... 35) keV X-rays

Field size

(0.5 x 0.5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(20 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Type of productvented plane parallel
ionization chamber

Application

absolute dosimetry in lowenergy photon beams

Measuring quantities

absorbed dose to water,
air kerma, exposure

Reference radiation
quality

30 kV, HVL 0.37 mm Al (T30)

Nominal sensitive
volume0.005 cm3

Designnot waterproof, vented

Reference pointin chamber center ofentrance foil underside

Direction of incidence

perpendicular to chamber
plane

Nominal response

200 pC/Gy

Long-term stability≤ 1 % per year

Chamber voltage

400 V nominal± 400 V maximal

Directional response≤ 5 % for chamber tilting
up to ± 10°

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

0.99 kGy/s
1.9 kGy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

4 mGy
10 mGyOrdering Information
TN34013 Soft X-ray chamber 0.005 cm3,
connecting system BNT
TW34013 Soft X-ray chamber 0.005 cm3,
connecting system TNC
TM34013 Soft X-ray chamber 0.005 cm3,
connecting system M

33

Therapy Detectors

SOURCECHECK 4π
Type 33005
Ionization chamber for measuring thesource strength of radioactive seeds andintravascular brachytherapy sources

Features
Measures low energy seeds and high energy
afterloading sources

Measures:
Inner well diameter
Outer dimensions

height 180 mmbase diameter 127 mm
outer well diameter 93 mm

Weight

1.4 kgMeasures all sources in a full 4π geometry
Adapters for all commercial afterloading devices
and seeds

32 mm

User friendly accessories for fast and safe handling
Compatible to high class PTW dosemeters
Calibration for Ir-192 and for I-125 available
The SOURCECHECK 4π well-type ionization chamber issuitable for source strength measurements of all kind ofbrachytherapy sources. International standards require
the measurement of radioactive brachytherapy sources.
For HDR afterloading sources an acceptance test after
the replacement of the source and additional constancy
checks are required. For permanent implanted seeds the
typical quality assurance is measuring a defined amountseeds out of a delivered batch.
Various adapters for all kind of afterloading applicatorsand for different seeds and seed strands are available.
The radioactive check source T48010 can be used forconstancy checks. The chamber can be calibrated for
Ir-192 and for I-125.

Specification
Type of productwell-type ionizationchamber

Application

source strength measurement of brachytherapy
sources

Measuring quantities

apparent activity
air kerma strength
exposure strength

Calibration

Ir-192, I-125, others uponrequestNominal response

125 fA/MBq (Ir-192)
65 fA/MBq (I-125)

Nominal volume

116 cm3

Designvented, guarded

Chamber voltage

400 V nominal

Reference point

87 mm below chamber top

Long-term stability≤ ± 1 % per year

Leakage current≤ ± 50 fA

34

Useful ranges:
Temperature(10 ... 40) °C for sources> 100 keV photons(15 ... 35) °C for sources< 100 keV photons or< 1 MeV electrons

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering Information
TN33005 SOURCECHECK 4π, connecting system BNT
TW33005 SOURCECHECK 4π, connecting system TNC
TM33005 SOURCECHECK 4π, connecting system M

Options
T33004.1.012 HDR Universal Adapter 1.0 – 1.8 mm
T33004.1.013 HDR Universal Adapter 1.8 – 3.2 mm
T33004.1.014 HDR Universal Adapter 3.2 – 4.6 mm
T33004.1.015 HDR Universal Adapter 4.5 – 5.9 mm
T33004.1.016 HDR Universal Adapter 5.8 – 7.2 mm
T33002.1.009 Adapter for Nucletron AL
T33005.1.100 SOURCECHECK single seed adapter
T33005.1.150 SOURCECHECK seed adapter Nucletron
T33005.1.130 SOURCECHECK strand adapter
T33005.1.120 SOURCECHECK Rapid Strand adapter
T33005.1.020 SOURCECHECK radioactive check source
adapter
T48010 Check device 90-Sr, point source
E21272 SOURCECHECK calibration Ir-192
E21271 SOURCECHECK calibration I-125

Therapy Detectors

System Incorporated Detectors
for Radiotherapy
Besides the radiation detectors presented in this chapter, there are available a number of further detectors which areincorporated components of therapy dosemeters. Firstly there are detectors used for in-vivo dosimetry during therapeutic treatments to control the radiation load given to patients. Secondly state-of-the-art linear and planar detector matrices for dose distribution measurements of intensity modulated therapy beams (IMRT) are part of the PTW detector range.

Patient in-vivo Detectors
Semiconductor probes for in-vivo dosimetry are fixed to the patient’s body tomeasure the patient skin, entrance or exit dose during external radiation treatments. Three different detector types for photon energies and one type for electron measurements are available. Additionally a risk organ diode with increased
sensitivity and homogeneous directional response is available.

LA48 Linear Chamber Array
The LA48 linear chamber array is designed specially for fast, accurate and reliable
dynamic field dosimetry measurements of virtual wedges and multileaf collimators. It incorporates the latest development in fluid-filled ion chamber technology
into an advanced ion chamber array. The combination of speed, accuracy andspatial resolution is simply not possible with other systems.

OCTAVIUS Detector 729 Chamber Array
The OCTAVIUS Detector 729 is a new concept of an ion chamber matrix in aplane for IMRT verification and quality control in radiation therapy. There are 729
vented plane-parallel ion chambers located in a matrix of 27 x 27. Utilizing ion
chambers avoids radiation defects, the major drawback of solid-state detectors.

OCTAVIUS Detector 1000 SRS Chamber Array
The OCTAVIUS Detector 1000 SRS is the first liquid-filled 2D ionization chamberarray. The very small detector size of only 2.3 mm x 2.3 mm x 0.5 mm makes
this array ideal suited for dosimetry of small fields.
Target application is patient plan verification in stereotactic radio surgery andquality assurance of small fields.

STARCHECK Planar Chamber Array
STARCHECK is a precise and reliable tool for fast measurements in radiation
therapy beams. Typical applications are quality control and LINAC beam adjustment. The 527 ionization chambers feature an excellent relative response stability, avoiding the need of frequent recalibration. The excellent spatial resolutionof only 3 mm ensures precise measurements even in penumbra regions.

STARCHECKmaxi Planar Chamber Array
STARCHECKmaxi is a precise and reliable tool for fast measurements in radiation therapy beams. Typical applications are quality control and LINAC beam adjustment. The
707 ionization chambers feature an excellent relative response stability, avoiding theneed of frequent recalibration. It combines the high-resolution of 3 mm as known
from the STARCHECK with the ability to cover fields up to a size of 40 cm x 40 cm.
Details upon request35Check Devices

Radioactive 90Sr Check Devices
Radioactive check devices are used for air density corrections of vented ionization chambers and for constancy checks ofthe complete dosemeters including chamber. Appropriate holding devices to reproducibly adapt the various ion chambers to the radioactive check devices are available.

T48012 Check Device for Thimble Chambers
The check device type T48012 is specially designed for thimble chambers andincludes an encapsulated 90Sr source with a low activity of 33 MBq. The sensitive
volume of the inserted chamber is irradiated from all directions. The check device
is supplemented by a thermometer for controlling its inside temperature. The
source is equivalent to ISO class C64444.

T48010 Check Device for Flat Chambers
The check device type T48010 is specially designed for flat chambers andincludes an encapsulated 90Sr source with a low activity of 20 MBq. The cylindrical source of the check device is placed near to the entrance window of theion chamber by means of the appropriate holding device. The source is equivalent to ISO class C6X444.
Details upon request

36

Diagnostic Detectors

Diagnostic Detectors

Diagnostic Detectors

CT Chamber 3.14 cm338

CT Chamber 9.3 cm339

SFD Chamber 75 cm340

SFD Chamber 6 cm3

41

R/F/D and MAM Detectors

42

System Incorporated Detectors

43

37

Diagnostic Detectors

CT ChamberType 30009
Vented cylindrical pencil chamber fordose length product measurements incomputed tomography

Features
Pencil type chamber for measurements within
a CT head or body phantom or free in air
Provides a sensitive measuring length of 10 cm
Shows a homogeneous response over the wholechamber length
The CT chamber is a vented cylinder chamber designed
for dose length product and dose length product ratemeasurements in computed tomography. The chamberallows the determination of the CTDI1001, CTDIW2 andCTDIVol3 according to IEC 61223-2-6 and IEC 61223-3-5.

Specification
Type of productvented pencil type chamber

Application

dosimetry in computed
tomography

Materials and measures:
Wall material
1 mm PMMA,
graphite coated
Wall area density

119 mg/cm2

Dimension of sensitive
volumeradius 3.5 mm
length 100 mm

Electrode

Al tube, graphited
outer diameter 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
274 µsMax. dose rate for≥ 95.0 % saturation

12.4 Gy/s

Max. dose per pulse for≥ 95.0 % saturation

2.26 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Measuring quantities

air kerma length product,
exposure length productRadiation quality(50 ... 150) kV

Reference radiation
quality

120 kV, HVL 8.4 mm Al(RQT9)

Temperature(10 ... 40) °C(50 ... 104) °F

Nominal sensitive
volume3.14 cm3

Humidity(10 ... 80) %, max 20 g/m3

Designnot waterproof, vented,
pencil type

Air pressure(700 ... 1060) hPa

Reference point

chamber center

Ordering Information

Direction of incidence

radialNominal response

14 nC/(Gy·cm)

Chamber voltage- 100 V nominal± 500 V maximal
high voltage to be connected
only with active current-limiting device (Imax < 0.5 mA)

TN30009 CT chamber 3.14 cm3, connecting system BNT
TW30009 CT chamber 3.14 cm3, connecting system TNC
TM30009 CT chamber 3.14 cm3, connecting system M
TL30009 CT chamber 3.14 cm3, connecting system L

Energy response≤ ± 5 % for(70 ... 150) kV

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

38

1CTDI

100 = Computed Tomography Dose Index 100
2CTDI = Weighted CTDI
W
100
3CTDI = Volume CTDI
Vol

W

Diagnostic Detectors

CT ChamberType 30017
Vented cylindrical pencil chamber fordose length product measurements incomputed tomography

Features
Pencil type chamber for measurements free in air
Provides a sensitive measuring length of 30 cm
Shows a homogeneous response over the wholechamber length
The CT chamber is a vented cylinder chamber designed
for dose length product and dose length product ratemeasurements in computed tomography according to
the amendment to IEC 60601-2-44.

Specification

Materials and measures:
Wall material
1 mm PMMA,
graphite coated
Wall area density

119 mg/cm2

Dimension of sensitive
volumeradius 3.5 mm
length 300 mm

Electrode

Al tube, graphited
outer diameter 3 mm

Ion collection efficiency at nominal voltage:
Ion collection time
274 µsType of productvented pencil type chamberMax. dose rate for≥ 95.0 % saturation

12.4 Gy/s

Application

dosimetry in computed
tomography

Max. dose per pulse for≥ 95.0 % saturation

2.26 mGy

Useful ranges:
Chamber voltage± (100 ... 400) V

Measuring quantities

air kerma length product,
exposure length product

Reference radiation
quality

120 kV, HVL 8.4 mm Al(RQT9)

Radiation quality(50 ... 150) kV

Nominal sensitive
volume9.3 cm3

Temperature(10 ... 40) °C(50 ... 104) °F

Designnot waterproof, vented,
pencil type

Humidity(10 ... 80) %, max 20 g/m3

Reference point

chamber center

Air pressure(700 ... 1060) hPa

Direction of incidence

radialNominal response

13 nC/(Gy·cm)

Chamber voltage- 100 V nominal± 500 V maximal
high voltage to be connected
only with active current-limiting device (Imax < 0.5 mA)

Energy response≤ ± 5 % for(50 ... 150) kV

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

Ordering Information
TN30017 CT chamber 9.3 cm3, connecting system BNT
TW30017 CT chamber 9.3 cm3, connecting system TNC
TM30017 CT chamber 9.3 cm3, connecting system M
TL30017 CT chamber 9.3 cm3, connecting system L

39

Diagnostic Detectors

75 cm3 SFD
Diagnostic ChamberType 34060
Shadow-free plane parallel chamber
for absolute dosimetry in diagnostic
radiology

FeaturesShadow-free design for use with automatic exposure
control / brightness control
Sensitive volume 75 cm3, vented to air
Suitable for measurements in front of and behinda phantom
The 34060 SFD diagnostic chamber is a general purpose,high precision chamber for measurements in diagnostic
radiology. The chamber complies with the standard
IEC 61674. Its shadow-free design makes it possible touse the chamber even while the automatic exposure
control or brightness control is activated. Together withan adequate diagnostic dosemeter the chamber features
a wide dynamic range for measurements either in frontof or behind a patient-equivalent phantom. The lengthof the mounted connection cable is 2.5 m.

Specification
Type of productvented plane parallel
ionization chamberacc. IEC 61674

Materials and measures:
Entrance window
0.6 mm polycarbonate,1.55 g/cm3
0.002 mm graphite
0.32 g/cm3
Total window area density 93 mg/cm2
Water-equivalent window
thickness

0.9 mmSensitive volume

radius 45.7 mm
depth 2 x 5.71mm

Ion collection efficiency at nominal voltage:
Ion collection time
1 ms
Max. dose rate for≥ 99 % saturation≥ 95 % saturation

0.16 Gy/s
0.78 Gy/s

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality(25 ... 150) kV X-rays

Field size

(11 x 11) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Application

absolute dosimetry indiagnostic radiology

Measuring quantities

air kerma, exposure

Reference radiation
quality

70 kV, HVL 2.58 mm Al(RQR5)

Nominal sensitive
volume75 cm3

Ordering Information

Designnot waterproof, vented

TN34060 SFD diagnostic chamber 75 cm3,
connecting system BNT

Reference pointin chamber center

Direction of incidence

perpendicular to chamber
plane, see label 'Focus'

Nominal response

2.8 µC/Gy

Long-term stability≤ 0.5 % per year

Chamber voltage

200 V nominal± 400 V maximal

Energy response≤ ± 2 % (50 ... 150) kV

Polarity effect≤1%

Directional response≤ 3 % for chamber tilting
up to ≤ ± 15°

Leakage current≤ ± 5 fA

Cable leakage≤ 1 pC/(Gy·cm)

40

TW34060 SFD diagnostic chamber 75 cm3,
connecting system TNC
TM34060 SFD diagnostic chamber 75 cm3,
connecting system M
TL34060 SFD diagnostic chamber 75 cm3,
connecting system L

Diagnostic Detectors

6 cm3 SFD
Mammo ChamberType 34069
Shadow-free plane parallel chamber
for absolute dosimetry in diagnostic
radiology and mammography

FeaturesShadow-free design for use with automatic exposure
controlSensitive volume 6 cm3, vented to air
Suitable for measurements in front of and behinda phantom
The 34069 SFD mammo chamber is a high precisionchamber for measurements in diagnostic radiology athigh dose rates and in mammography. The chambercomplies with the standard IEC 61674. Its shadow-freedesign makes it possible to use the chamber even while
the automatic exposure control is activated. Together
with an adequate diagnostic dosemeter the chamber features a wide dynamic range for measurements either infront of or behind a patient-equivalent phantom. The
length of the mounted connection cable is 2.5 m.

Specification
Type of productvented plane parallel
ionization chamberacc. IEC 61674

Application

absolute dosimetry indiagnostic radiology

Measuring quantities

air kerma, exposure

Reference radiation
quality

30 kV, HVL 0.337 mm Al(RQR-M3)
70 kV, HVL 2.58 mm Al(RQR5)

Materials and measures:
Entrance window
0.32 mm PMMA,
1.19 g/cm3
0.002 mm graphite
0.32 g/cm3
Total window area density 38 mg/cm2
Water-equivalent window
thickness

0.4 mmSensitive volume

radius 15.2 mm
depth 2 x 4.21mm

Ion collection efficiency at nominal voltage:
Ion collection time
550 µsMax. dose rate for≥ 99 % saturation≥ 95 % saturation

0.53 Gy/s
2.65 Gy/s

Useful ranges:
Chamber voltage± (100 ... 400) V

Radiation quality(25 ... 150) kV X-rays

Field size

(5 x 5) cm2 ... (40 x 40) cm2

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering Information

Nominal sensitive
volume

6 cm3

TN34069 SFD mammo chamber 6 cm3,
connecting system BNT

Designnot waterproof, vented

Reference pointin chamber center

TW34069 SFD mammo chamber 6 cm3,
connecting system TNC

Direction of incidence

perpendicular to chamber
plane, see label 'Focus'

Nominal response

230 nC/Gy

Long-term stability≤ 2 % per year

Chamber voltage

200 V nominal± 400 V maximal

Energy response≤ ± 2 % (25 ... 35) kV

Polarity effect≤ 1 % (≤ 2 %)Directional response≤ 3 % for chamber tilting
up to ≤ ± 15°

Leakage current≤ 5 fA

Cable leakage≤ 1 pC/(Gy·cm)

TM34069 SFD mammo chamber 6 cm3,
connecting system M
TL34069 SFD mammo chamber 6 cm3,
connecting system L

41

Diagnostic Detectors

R/F/D and MAM
Detectors
Types 60004, 60005
Semiconductor detectors for diagnostic
X-raysFeatures
Fully comply with IEC 61674

Measures:
Dimension of volume

Small size and lightweight precision probes
For acceptance testing, service and QC in
X-ray diagnostics
The R/F/D and MAM detectors are sturdy semiconductor
detectors designed to withstand tough handling. Air
density corrections with a radioactive check device ormeasurement of air pressure and temperature are unnecessary. Both detectors do not need a high voltage
supply. Fully compliant to IEC 61674 they are suitable formeasurements during acceptance tests, service and quality control procedures.
Two detector types are available, covering either the radiography/fluoroscopy and dental range (40 … 150) kV or
the mammography range (25 … 45) kV.
The following quantities can be measured in conjunction
with e.g. the NOMEX Dosemeter:
air kerma and dose (with an additional absorber) in
the conventional range
air kerma and dose (with an additional absorber) in
the dental range
air kerma and dose (with additional 2 mm Al) in
mammographydose per pulse and number of pulses in fluoroscopy
and irradiation time.

Specification
Type of productsemiconductor detector

Application

absolute dosimetry indiagnostic radiology

Measuring quantities

air kerma, exposure

Reference radiation
qualities

30 kV, HVL 0.337 mm Al(RQR-M3)
70 kV, HVL 2.58 mm Al(RQR5)

Reference point

5.7 mm below the top side

Direction of incidence

perpendicular to detector
plane

Nominal responsetype 60005: 15 µC/Gy
type 60004: 40 µC/Gy

Long-term stability≤ ± 1 % per year

Energy response≤±5%

Leakage current≤ ± 100 fA

Cable leakage≤ 1 pC/Gy*cm

42

Outer dimensions
Useful ranges:
Radiation qualities

type 60005:
2x diameter 5.04 mm
type 60004:
diameter 11.28 mm
40 mm x 30 mm x 12 mm(25 ... 45) kV X-rays(RQR-M, MRV, WAV, WRV,
WSV, RRV)(40 ... 150) kV X-rays(RQR2 ... RQR10, RQA2 ...
RQA10)

Temperature(10 ... 40) °C(50 … 104) °F

Humidity(10 ... 80) %, max. 20 g/m³

Air pressure(700 ... 1060) hPa

Ordering Information
Connecting system TNC or L:
60004 R/F/D Detector
60005 MAM Detector

Diagnostic and Nuclear Medicine Detectors

System Incorporated Detectors
for Diagnostic Radiology
Besides the radiation detectors presented in this chapter, there are available a number of further detectors which areincorporated components of diagnostic dosemeters.

DIAMENTOR Patient Dosimetry Chambers
DIAMENTOR chambers for dose area product measurements are available indifferent sizes and types to cover a wide range of diagnostic X-ray installations.
The chambers can easily be mounted to the X-ray collimator or are firmly
installed parts of the X-ray installation. The transparent models do not interferewith the collimators light field diaphragm.

NOMEX Multimeter
The NOMEX Multimeter is a miniaturized non-invasive measuring system
for absolute dosimetry and quality control in X-ray diagnostic radiology.
It can be used for radiography, fluoroscopy, dental, CT and mammography(Mo/Mo, Mo/Rh, W/Al, W/Rh, W/Ag, Rh/Rh) application.

XLS X-Ray Leakage ChamberThis rectangular plane parallel XLS ionization chamber is used as part of the
XLS X-ray leakage system for radiation leakage measurements of diagnostic
X-ray installations. Up to 18 of these chambers can be arranged for radiation
leakage detection around X-ray tubes.

System Incorporated Detectors
for Nuclear Medicine
Besides detectors used in nuclear medicine presented in other chapters, e.g. for radiation protection measurements,
a special chamber as an incorporated component of the CURIEMENTOR system is available.

Well-type Chamber for CURIEMENTOR
Isotope Calibrator
The CURIEMENTOR chamber is a pressurized well-type ionization chamberwith nearly 4π measuring geometry. It is part of the CURIEMENTOR system
which measures the activity of radioactive isotopes as used in diagnostic andtherapeutic nuclear medicine and in intravascular brachytherapy.

Details upon request

43

Notes

Notes

44

Health Physics Detectors

Health Physics
Detectors

Health Physics Detectors

Radiation Monitoring Chamber 3 l

46

Radiation Monitoring Chamber 50 l

47

Spherical Chambers 1 l

48

Spherical Chambers 10 l

49

Spherical Chambers PS-10 and PS-50

50

Spherical Chamber TK-30

51

Cylinder Stem Chamber 30 cm3

52

Hp(10) Secondary Standard Chamber

53

Monitor Chambers for Calibration Facilities

54

Monitor Chambers for X-Ray Therapy Units

55

Böhm Extrapolation Chamber

56

45

Health Physics Detectors

3 Liter Radiation
Monitoring Chamber
Types 34031
Cylindrical polyethylene ionizationchamber for stationary radiation
monitoring of gamma radiation

Features
Vented sensitive volume of 3 liters
Suitable as radiation monitoring chamber
Gamma energy range 80 keV to 1.3 MeV
The 3 liter chamber is used as a stationary surveillance
device for environmental radiation monitoring. The
chamber is designed to measure protection level dose
rates. The chamber is fully guarded up to the sensitive
volume. Since the sensitive volume is open to the surroundings, air density correction is required for precise
measurement. The cylindrical chamber is made ofgraphite coated polyethylene with 4 mm wall thickness.
The ion-collecting electrode is made of graphite coatedpolyethylene too. The external chamber diameter is
150 mm and the length is approx. 200 mm. For thetransfer of the measuring signal and the polarizing
voltage, the chamber is supplied with two coaxial
connectors. The maximal chamber polarizing voltage is1000 V. The chamber is supplied with an integrated
adapter for positioning a radioactive check source oftype T48010, which makes it possible to check the proper performance of the entire measuring system.

Materials and measures:
Wall of sensitive volume
4 mm PE graphite coated,
0.95 g/cm3
Total wall area density

0.38 g/cm2

Dimension of sensitive
volumeradius 71.25 mm
length 200 mm

Central electrodegraphite coated PE,
diameter 28 mm

Outer dimensions

diameter 150 mm
length 200 mm

Ion collection efficiency at nominal range:
Ion collection time
25 ms
Max. dose rate for≥ 99 % saturation≥ 90 % saturation

0.95 Sv/h
9.5 Sv/h

Useful ranges:
Radiation quality

80 keV ... 1.3 MeV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Specification
Ordering Information

Type of productvented cylindrical ionizationchamber

Application

radiation monitoring

Measuring quantity

photon equivalent dose

Nominal sensitive
volume3l

OptionDesignnot waterproof, vented

T7262/U10-1.5 Connection cable with M connector,
length 1.5 m

Reference point

chamber center

Direction of incidence

radialNominal response

100 µC/Sv

Chamber voltage

1000 V nominal

Energy response≤ ± 10 % (Ephoton ≥ 80 keV)

Directional response in air≤ ± 10 % for tilting
perpendicular to the axis
up to ± 20°

Leakage current≤ ± 50 fA

46

T34031 Radiation monitoring chamber 3 l,Fischer coax connectors

Health Physics Detectors

50 Liter Radiation
Monitoring ChamberType 7262
Cylindrical pressurized steel ionizationchamber for stationary gamma
radiation monitoring

Features
Suitable as stationary radiation monitoring chamber

Materials and measures:
Wall of sensitive volume
3 mm Al, 2.7 g/cm3
3.25 mm steel,
7.85 g/cm3

Gamma energy range 80 keV to 1.3 MeV

Total wall area density

3.361 g/cm2

Dimension of sensitive
volumeradius 66.75 mm
length 360 mm

Central electrodebrass, diameter 17.5 mm

Outer dimensions

diameter 195 mm
length 538 mm

Sealed sensitive volume of 50 liters

The ionization chamber T7262 has a constructive volumeof 5 liters filled with Argon gas at the pressure of 10 bar,
resulting in an effective sensitive volume of 50 liters. This
superior design makes the chamber very sensitive andenables performing low level gamma radiation measurements down to the natural radiation background. The
chamber is used as highly sensitive stationary surveillance
device for environmental radiation monitoring. The
chamber is fully guarded up to the sensitive volume.
Since the sensitive volume is sealed, no air density correction is required. The cylindrical 50 liter chamber ismade of steel with 3.25 mm wall thickness and a 3 mmaluminum cover. The ion-collecting electrode is made ofbrass. The external chamber diameter is 195 mm and thelength is 538 mm. The chamber is supplied with two
coaxial Fischer connectors for the transfer of the measuring signal and the polarizing voltage. Via an optional
adapter cable of 1.5 m length, the chamber can be connected to a dosemeter with M connector, which has
input circuits on ground potential. The maximal chamberpolarizing voltage is 1000 V.

Ion collection efficiency at nominal range:
Ion collection time
30 ms
Max. dose rate for≥ 99 % saturation≥ 90 % saturation

1 mSv/h
10 mSv/h

Useful ranges:
Radiation quality

80 keV ... 1.3 MeV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering Information
T7262 Radiation monitoring chamber 50 l,Fischer coax connectors

Specification
Type of productpressurized cylindricalionization chamber

Application

radiation monitoring

Measuring quantity

photon equivalent dose

Nominal sensitive
volume50 l

Designsealed and pressurized,
filled with Ar (10 bar)

Reference point

chamber center

Direction of incidence

radialNominal response

2 mC/Sv.

Chamber voltage

1000 V nominal

Energy response≤ ± 10 % (Ephoton ≥ 80 keV)

Directional response in air≤ ± 10 % for tilting
perpendicular to the axis
up to ± 20°

Leakage current≤ ± 50 fA

Option
T7262/U10-1.5 Connection cable with M connector,
length 1.5 m

47

Health Physics Detectors

1 Liter Spherical
Ionization ChamberType 32002
Spherical ionization chamber forradiation protection

Features
Vented sensitive volume of 1 liter
Suitable for survey meter calibration and low levelmeasurements
Superior energy response, reproducibility,
directional dependence and long-term stability
Radioactive check device (option)
The spherical chamber is designed for the measurementof ionizing radiation in radiation protection. Superiorfeatures make the chamber suitable as standard chamber for calibration purposes. It fulfills the requirement for
excellent reproducibility and long-term stability of thesensitive volume. The spherical construction ensures anearly uniform response to radiation from every direction. The energy response is very flat. This is achieved by
the thin layer of aluminum on the inner wall surface,which provides for an increased photoelectric yield tocompensate for the absorption of soft X-rays. The outerchamber diameter is 140 mm.

Specification

Materials and measures:
Wall of sensitive volume
3 mm POM(polyoxymethylene)
Total wall area density

453 mg/cm2

Central electrodegraphite coated polystyrene,

diameter 50 mm
Outer dimension

diameter 140 mm

Ion collection efficiency at nominal range:
Ion collection time
37 ms
Max. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

210 mGy/h
420 mGy/hMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

1.6 µGy
3.1 µGy

Useful ranges:
Chamber voltage± (300 ... 500) V

Radiation quality

25 keV ... 50 MeV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Type of productvented spherical ionizationchamber

Application

radiation protection
measurements

Measuring quantity

photon equivalent dose

Ordering information

Nominal sensitive volume

1l

Designnot waterproof, vented

Reference point

chamber center

TN32002 Spherical chamber 1 l, connecting system BNT
TW32002 Spherical chamber 1 l, connecting system TNC
TM32002 Spherical chamber 1 l, connecting system M

Nominal response

40 µC/Gy

Options

Chamber voltage

400 V nominal± 500 V maximal

T48010 Radioactive check device 90Sr
T48001 Chamber holding device for check device

Energy response≤ ± 4 % (32002)

Leakage current≤ ± 10 fA

48

Health Physics Detectors

10 Liter Spherical
Ionization ChamberType 32003
Spherical ionization chamber forradiation protection

Features
Vented sensitive volume of 10 liters
Suitable for survey meter calibration and low levelmeasurements
Superior energy response, reproducibility,
directional dependence and long-term stability
Radioactive check device (option)
The spherical chamber is designed for the measurementof ionizing radiation in radiation protection. Superiorfeatures make the chamber suitable as standard chamber for calibration purposes. It fulfills the requirement for
excellent reproducibility and long-term stability of thesensitive volume. The spherical construction ensures anearly uniform response to radiation from every direction. The energy response is very flat. This is achieved by
the thin layer of aluminum on the inner wall surface,which provides for an increased photoelectric yield tocompensate for the absorption of soft X-rays. The outerchamber diameter is 276 mm.

Specification

Materials and measures:
Wall of sensitive volume
2.75 mm POM(polyoxymethylene)
Total wall area density

417 mg/cm2

Central electrodegraphite coated polystyrene,
diameter 100 mm

Outer dimensions

diameter 276 mm

Ion collection efficiency at nominal range:
Ion collection time
150 msMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

13 mGy/h
26 mGy/hMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

0.3 µGy
0.8 µGy

Useful ranges:
Chamber voltage± (300 ... 500) V

Radiation quality

25 keV ... 50 MeV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Type of productvented spherical ionizationchamber

Application

radiation protection
measurements

Measuring quantity

photon equivalent dose

Ordering information

Nominal sensitive volume

10 l

Designnot waterproof, vented

Reference point

chamber center

TN32003 Spherical chamber 10 l, connecting system BNT
TW32003 Spherical chamber 10 l, connecting system TNC
TM32003 Spherical chamber 10 l, connecting system M

Nominal response

330 µC/Gy

Options

Chamber voltage

400 V nominal± 500 V maximal

T48010 Radioactive check device 90Sr
T48001 Chamber holding device for check device

Energy response≤±3%

Leakage current≤ ± 10 fA

49

Health Physics Detectors

PS-50 and PS-10
Spherical Chambers
Types 32007S, 32008S
Primary standard spherical ionizationchambers for radiation protection
measurements

Features
Vented sensitive volumes of 50 cm3 and 10 cm3

Materials and measures:
Wall of sensitive volume
3.5 mm graphite

Suitable as primary standard for radiation protection
measurements

Total wall area density

647 mg/cm2

Central electrodegraphite, diameter 3 mmExact volume individually determined

Outer dimensions

diameter 53 mm (32007S)
diameter 34 mm (32008S)

Designed in collaboration with the National Instituteof Standards and Technology (NIST)The spherical graphite chambers PS-50 and PS-10 are
vented ionization chambers for the use as primary standard for radiation protection measurements and for
absolute dosimetry. The spherical graphite chambers havebeen designed in collaboration with the Radiation
Interactions and Dosimetry Group at the National
Institute of Standards and Technology (NIST). The exact
volume of each chamber is individually determined. The
homogeneity of the walls and electrodes is 0.06 mm. The
chambers are constructed with a long rigid stem ofapprox. 29 cm length for easy mounting in the radiation
beam. Air density correction is required for each measurement.

Specification
Type of productvented spherical ionizationchambers

Application

primary standard forradiation protection
measurements

Ion collection efficiency at nominal range:
Ion collection time
8.7 ms (32007S)
1.9 ms (32008S)
Max. dose rate for≥ 99,5 % saturation≥ 90 % saturation
Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation(32007S), (32008S)
7.1 µG, 33 µGy
14.2 µGy, 65 µGy

Useful ranges:
Chamber voltage± (400 … 1000) V

Radiation quality

60Co, 137Cs

Field size (square field)≥ (6 x 6) cm2 (32007S)≥ (4 x 4) cm2 (32008S)

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3
(700 ... 1060) hPa

Measuring quantity

air kerma,
photon equivalent dose

Air pressure

Nominal sensitive volume

50 cm3 (32007S)
10 cm3 (32008S)

Ordering information

Designnot waterproof, vented

Reference point

chamber center

Nominal response

1.73 µC/Gy (32007S)
0.349 µC/Gy (32008S)

Chamber voltage

1000 V nominal (32007S)500 V nominal (32008S)± 1000 V maximal

Directional response in air≤ ± 0.5 % for rotation
around the chamber axisand ≤ ± 1 % for tilting thechamber axis up to ± 60°(32007S) ≤ ± 1 % fortilting the chamber axis
up to ± 50° (32008S)

Leakage current≤ ± 5 fA

50

(32007S), (32008S)
1.23 mGy/s, 26 mGy/s
2.46 mGy/s, 52 mGy/s

TN32007S Spherical chamber PS-50,
connecting system BNT
TN32008S Spherical chamber PS-10,
connecting system BNT

Health Physics Detectors

Spherical Ionization
Chamber TK-30
Type 32005
Spherical ionization chamber with along rigid stem for radiation protection
measurement

Features
Vented sensitive volume of 28 cm3
Suitable as high precision reference chamber
for radiation protection dosimetry
Very flat energy response within a wide range
The spherical chamber TK-30 is designed as a referencechamber for absolute dosimetry to be used by secondary
standard dosimetry laboratories (SSDL) and users withhigh quality requirements. It has very small variations ofresponse with radiation quality from low X-ray energies up
to high-energy photon radiation. The guard ring isdesigned up to the sensitive volume. The chamber is constructed with a long rigid stem of approx. 20 cm length foreasy mounting in the radiation beam. Air density correction is required for each measurement.

Materials and measures:
Wall of sensitive volume
3 mm POM(polyoxymethylene,graphite coated)
Total wall area density

453 mg/cm2

Dimension of sensitive
volumeradius 22 mm

Central electrodegraphite coated PMMA,
diameter 4.2 mm

Ion collection efficiency at nominal range:
Ion collection time
4.5 msMax. dose rate for≥ 99 % saturation≥ 90 % saturation

29.4 Gy/h
294 Gy/hMax. dose per pulse for≥ 99 % saturation

26 µGyvented spherical ionizationchamber

Useful ranges:
Chamber voltage± (200 ... 400) V

Application

radiation protection
measurements

Radiation quality

25 keV ... 50 MeV

Temperature

Measuring quantity

photon equivalent dose,
exposure(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Nominal sensitive
volume27.9 cm3

Air pressure(700 ... 1060) hPa

Designnot waterproof, vented

Reference point

chamber center

Direction of incidence

radialNominal response

900 nC/Gy

Chamber voltage

400 V nominal± 1000 V maximal

Energy response≤ ± 5 % (48 keV ... 60Co)

Directional response in air≤ ± 0.5 % for rotation
around the chamber axisand ≤ ± 3 % for tilting of
the axis up to ± 45°

Leakage current≤ ± 5 fASpecification
Type of product

Ordering information
TN32005 Spherical chamber TK-30,
connecting system BNT
TW32005 Spherical chamber TK-30,
connecting system TNC
TM32005 Spherical chamber TK-30,
connecting system M

51

Health Physics Detectors

30 cm3 Cylinder Stem
Ionization ChamberType 23361
Cylindrical PMMA ionization chamberwith a long rigid stem for radiation
protection measurement

Features
Vented sensitive volume of 30 cm3
Suitable as high precision reference chamber
for radiation protection dosimetry
Very flat energy response within a wide range
Radioactive check device (option)
The cylinder stem chamber is designed as a referencechamber for absolute dosimetry to be used by secondary
standard dosimetry laboratories (SSDL) and users withhigh quality requirements. It has very small variations ofresponse with radiation quality from low X-ray energies up
to high-energy photon radiation. The guard ring isdesigned up to the sensitive volume. The chamber is constructed with a long rigid stem of approx. 20 cm length foreasy mounting in the radiation beam. An acrylic build-up
cap with 3 mm wall thickness for in-air measurement in
60Co beams is included with each chamber, as well as acalibration certificate. Air density correction is required foreach measurement. A radioactive check device and an
appropriate holding device are available.

Specification

Materials and measures:
Wall of sensitive volume
1 mm PMMA, graphited
Total wall area density

119 mg/cm2

Dimension of sensitive
volumeradius 15.5 mm
length 51 mm

Central electrodegraphite coated Al,
diameter 14 mm

Outer dimensions

diameter 33 mm
length 335 mm

Build-up cap

PMMA, thickness 3 mm

Ion collection efficiency at nominal range:
Ion collection time
1.3 msMax. dose rate for≥ 99.5 % saturation≥ 99.0 % saturation

60 mGy/s
120 mGy/s

Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

50 µGy100 µGy

Useful ranges:
Radiation quality

30 keV ... 50 MeV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Type of productvented cylindricalionization chamber

Application

radiation protection
measurements

Measuring quantity

photon equivalent dose,
exposure

Nominal sensitive
volume30 cm3

TN23361 Cylinder stem chamber 30 cm3,
connecting system BNT

Designnot waterproof, vented

Reference point

on chamber axis,
27 mm from chamber tip

TW23361 Cylinder stem chamber 30 cm3,
connecting system TNC

Direction of incidence

radialNominal response

1 µC/Gy

Chamber voltage

400 V nominal± 500 V maximal

Energy response≤ ± 4 % (40 keV ... 60Co)

Directional response in air≤ ± 0.5 % for for rotation
around the chamber axis
for tilting see diagram page 66

Leakage current≤ ± 10 fA

Stem leakage≤ 1 pC/(Gy·cm)

52

Ordering information

TM23361 Cylinder stem chamber 30 cm3,
connecting system M

Options
T48010 Radioactive check device 90Sr
T23237 Chamber holding device for check device

Health Physics Detectors

Hp(10) Secondary
Standard ChamberType 34035
Parallel plate ionization chamber for
direct measurement of Hp(10) personaldose equivalent on a slab phantom

Vented sensitive volume of 10 cm3

Materials and measures:
Phantom material
PMMA

Measures the Hp(10) personal dose equivalent directly

Outer dimensions

300 mm x 300 mm

Suitable as a reference chamber for Hp(10) calibrationchamber assembly

height 31 mm

additional slab phantom

height 120 mm

Features

The parallel plate ionization chamber model 340351 is
integrated into a slab phantom to measure the Hp(10)radiation protection measuring quantity directly. The
high performance chamber is designed to be used as asecondary standard chamber for calibration purposes.
The beam calibration with the Hp(10) chamber makes it
unnecessary to precisely determine the spectrum of the
X-ray beam. The chamber comes uncalibrated; a primary
standard calibration by PTB, the German National
Laboratory, is available. The chamber set includes aphantom slab of 31 mm thickness with chamber assembly and an additional PMMA phantom slab of 120 mm
thickness. Both sets available include an adapter cable toconnect the chamber either to a dosemeter with M connector or with BNC connector and banana pin. The
Hp(10) chamber should be used in connection with ahigh quality dosemeter such as UNIDOS, UNIDOS E or
UNIDOSwebline to ensure best performance.

Useful ranges:
Chamber voltage± (300 ... 500) V

Radiation quality(15 ... 1400) keV

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering information
L981937 Hp(10) Secondary standard chamber type34035, connecting system M
L981938 Hp(10) Secondary standard chamber type34035, connecting system BNC and banana pin

OptionPTB Primary standard calibration upon request

Specification
Type of productvented parallel plate chamber

Application

radiation protection
measurements

Measuring quantity

Hp(10) personal dose
equivalent

Nominal sensitive volume

10 cm3

Designnot waterproof, vented

Reference conditions

20°C, 1013 hPa 65 % rel.
humidity

Reference point

chamber center, 13.5 mm
below chamber surface or15.5 mm below surface ofintegrated step cylinder

Nominal response

285 nC/Sv

Chamber voltage

400 V nominal

Leakage current≤ ± 10 fA

Cable leakage≤ 1 pC/(Gy·cm)

1 Ankerhold, Ambrosi, Eberle – A chamber for determining the conventionally true value of Hp(10) and H*(10) needed by calibration laboratories – Rad. Prot. Dos. Vol. 96, Nos 1-3, pp. 133 - 137 (2001), Nucl.
Techn. Publishing53

Health Physics Detectors

Monitor Ionization
Chambers
Types 34014, 786
Large size plane parallel transmission
chambers for use as dose monitors
combined with calibration facilities

Features
Vented sensitive volumes of 94 cm3 and 86 cm3
Include twin-sensitive volumes
Shadow-free transmission chambers for dosemonitoring with calibration facilities
The circular plane parallel transmission chambers
are used for dose monitoring in combination with calibration benches. The sensitive volumes are designed
as twin-chambers with 2.5 mm measuring depth eachand a diameter of 155 mm (model 786) or 148 mm(model 34014). The chamber walls and the electrodes
are made of polyimide (PI) of 0.025 mm thickness eachwith graphite layer. The chambers are fully guarded. The
external diameter of the chamber housing is 230 mm.
Two holes with 6 mm threads serve for mechanicalchamber fixation.

Materials and measures:
Entrance window
3 x 0.025 mm polyimide,
graphite coatedTotal window area density 3 x 3.55 mg/cm2
Electrodepolyimide foil, graphite
coatedOuter dimensions

diameter 230 mm

Ion collection efficiency at nominal voltage:
Max. dose rate for≥ 99.5 % saturation
8.5 Gy/s≥ 99.0 % saturation
17 Gy/s (34014)
18 Gy/s (786)Max. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

590 µGy
1.19 mGy

Useful ranges:
Radiation quality(7.5 ... 420) kV X-rays

Two chamber versions are available: model 786 is used
together with dosemeters having the input circuits on
ground potential, and model 34014 is used together with
dosemeters having the input circuits on high voltage.

Field size

≤ 148 mm diameter (34014)≤ 155 mm diameter (786)Temperature(10 ... 40) °C(50 ... 104) °F

Specification

Humidity(10 ... 80) %, max 20 g/m3
(700 ... 1060) hPa

Type of productvented plane parallel
twin-chambers

Air pressure

Applicationdose monitoring incalibration facilities

Ordering information

Measuring quantity

exposure

Nominal sensitive
volumes

86 cm3 (34014)
94 cm3 (786)

Designnot waterproof, vented

Nominal response

depends on field size

Chamber voltage

400 V nominal

Leakage current≤ 1 pA

54

TN34014 Monitor chamber, connecting system BNT
TW34014 Monitor chamber, connecting system TNC
TM786 Monitor chamber, connecting system M
TB786 Monitor chamber, connecting system BNC
and banana pin
Monitor chambers with smaller diameter of sensitive
volume upon request

Health Physics Detectors

X-ray Therapy
Monitor ChamberType 7862
Large size plane parallel transmission
chamber for use as dose monitor
combined with X-ray therapy units

Features
Vented sensitive volume of 17.6 cm3
Shadow-free transmission chamber for dosemonitoring with radiation therapy X-ray equipment
The circular plane parallel transmission chamber model
7862 is used for dose monitoring in combination withradiotherapy X-ray units. The sensitive volume is designed as a very thin cylinder of 2.4 mm thickness and96.5 mm diameter. The chamber wall and the electrodeare made of polyimide (PI) of 0.05 mm thickness eachwith graphite layer, mechanically protected by anotherPI foil of 0.05 mm in front of each wall. The nominal
photon energy range is 7.5 kV up to 420 kV and theleakage current is less than 1 pA. The chamber is fully
guarded. The external diameter of the chamber housing
is 119.5 mm. Three holes with 3.5 mm threads serve formechanical chamber fixation. The transmission chambermodel 7862 is used in connection with dosemeters having the input circuits on ground potential.

Specification
Type of productvented plane parallel
triple-chamber

Applicationdose monitoring in X-ray
therapy units

Measuring quantity

exposure

Nominal sensitive
volume17.6 cm3

Designnot waterproof, vented

Nominal response

depends on field size

Chamber voltage

400 V nominal

Leakage current≤ 1 pA

Materials and measures:
Entrance window
4 x 0.05 mm polyimide,
graphite coatedTotal window area density 4 x 7.1 mg/cm2
Electrodepolyimide foil, graphite
coatedOuter dimensions

diameter 119.5 mm

Ion collection efficiency at nominal voltage:
Max. dose rate for≥ 99.5 % saturation
10 Gy/s≥ 99.0 % saturation
20 Gy/sMax. dose per pulse for≥ 99.5 % saturation≥ 99.0 % saturation

640 µGy
1.29 mGy

Useful ranges:
Radiation quality(7.5 ... 420) kV X-rays

Field size

≤ 95 mm diameter

Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering information
TM7862 Monitor chamber for X-ray therapy units,connecting system M

55

Health Physics Detectors

Böhm Extrapolation
Chamber
Type 23392
Low energy extrapolation chamber withadjustable volume depth for measurements of absorbed dose in soft tissue

Features
Measures absolute dose of beta radiation and
X-rays in soft tissue equivalent material very precisely
Includes a micrometer screw for the depth
adjustment of the sensitive volume down to zero

Materials and measures:
Entrance window
PET, graphite coatedTotal window area density 0.75 mg/cm2
Measuring electrode

diameter 30 mm

Rear electrode

PMMA, graphite coateddiameter 60.5 mm

Distance between
electrodes(0.5 ... 10.5) mm

Suitable for beta calibration at PSDLs and SSDLs
The Böhm extrapolation chamber is a high quality device
for absorbed dose measurements of beta and low energy
X radiation in certain depths below the surface of theentrance window. Primary standard dosimetry laboratories (PSDL) and secondary standard dosimetry laboratories (SSDL) use it for low energy radiation calibration. The
dose is determined from the ionization density ina small air gap, the extrapolation chamber volume,
embedded in tissue equivalent material (PMMA). The
chamber is supplied with a very thin entrance window of
0.75 mg/cm2 and a collecting electrode of 30 mm indiameter. By means of the built-in micrometer screw, thecollecting electrode surrounded by a guard ring of 15 mm
can be moved to adjust the depth of the sensitive volume
between 10.5 mm and 0.5 mm. The zero point of thechamber depth setting can be obtained by measuring thechamber capaciting charge C versus the chamber depth x and
extrapolating C-1 towards x = 0. The chamber is equippedwith two BNC sockets for signal and polarizing voltage. A
connection cable from both BNC sockets to an electrometerwith M type connector is available. An electrometer with the
input circuits on ground potential is required. The extrapolation chamber comes in a protective storage case.

Specification
Type of productextrapolation chamberaccording to Böhm

Application

absolute dosimetry of beta
radiation and X-rays

Measuring quantity

absorbed dose in soft tissue

Nominal sensitive volume(0.353 ... 7.422) cm3

Designnot waterproof, vented,
fully guarded

Reference pointin chamber center ofentrance foil underside

Nominal response

dependent on electrodedistance

Chamber voltage

dependent on electrodedistance 500 V maximal

Leakage current≤ 1 pA

Cable leakage≤ 1 pC/(Gy·cm)

56

Ion collection efficiency at nominal voltage:
Ion collection time anddependent on electrodemax. dose rate
distance
Useful ranges:
Temperature(10 ... 40) °C(50 ... 104) °F

Humidity(10 ... 80) %, max 20 g/m3

Air pressure(700 ... 1060) hPa

Ordering information
T23392 Böhm extrapolation chamber
T23392/U5 Connection cable for Böhm extrapolationchamber, connecting system M

Quick View

Quick View

Product Family Quick View

Drawings and Diagrams

58

Connector Design

68

Overview of PTW Detectors

70

57

Drawings

Drawings

Farmer Chamber

30010

Farmer Chamber

30011

Farmer Chamber

30012

Farmer Chamber

30013

0.125 cm3 Semiflex Chamber

31010

0.3 cm3 Semiflex Chamber

31013

58

Drawings

0.3 cm3 Rigid Stem Chamber

30016

1.0 cm3 Rigid Stem Chamber

30015

Advanced Markus Chamber

34045

Markus Chamber

23343

Roos Chamber

34001

10.5 cm3 Bragg Peak Chamber

34070

59

Drawings

2.5 cm3 Bragg Peak Chamber

34073

PinPoint Chamber

31014

PinPoint Chamber

31015

PinPoint 3D Chamber

31016

microDiamond

60019

Dosimetry Diode P

60016

60

Drawings

Dosimetry Diode E

60017

Dosimetry Diode SRS

60018

Dosimetry Diode PR

60020

0.02 cm3 Soft X-Ray Chamber

23342

0.2 cm3 Soft X-Ray Chamber

23344

0.005 cm3 Soft X-Ray Chamber

34013

61

Drawings

75 cm3 SFD Diagnostic Chamber

34060

SOURCECHECK 4π

33005

6 cm3 SFD Mammo Chamber

34069

3.14 cm3 CT Chamber

30009

9.3 cm3 CT Chamber

30017

62

Drawings

50 Liter Radiation Monitoring Chamber

7262

3 Liter Radiation Monitoring Chamber

34031

Spherical Ionization Chamber TK-30

32005

1 Liter Spherical Ionization Chamber

32002

10 Liter Spherical Ionization Chamber

32003

63

Drawings

50 cm3 Spherical Ionization Chamber PS-50

32007S

10 cm3 Spherical Ionization Chamber PS-10

32008S

30 cm3 Cylinder Stem Ionization Chamber

23361

30 cm3 Cylinder Stem Ionization Chamber
Directional response in air

23361

Hp(10) Secondary Standard Chamber

34035

Böhm Extrapolation Chamber

23392

64

Drawings

X-Ray Therapy Monitor Chamber

7862

Monitor Ionization Chamber

34014

Monitor Ionization Chamber

786

65

NotesNotes

67

Connectors

The Connector Design
The following overview of connecting systems facilitates the identification of the adequate connector to fit your measuringsystem. Outer shape, colors and the size of the housing may vary, depending on the production year and the manufacturer.
Some connectors may have protective covers which veil the real shape of the connector. All connectors are displayed without such protective covers. The images are not full-scale. See table on page 69 for approximate outer connector diameters.
Supply of detectors with BNC connectors with banana pin, BNC biax connectors and DIAMENTOR F type connectors
upon request.

BNT Connector (N Type)male

BNT Connector (n type)femaleTNC Connector (W type)male

TNC Connector (w type)femaleTriax PTW Connector (M type)male

Triax PTW Connector (m type)femaleBNC Connector with Banana Pin (B type)male

BNC Connector with Banana Pin (b type)femaleLEMO Connector (L type)

male

LEMO Connector (l type)female68

Connectors

DIAMENTOR Connector (V type)male

DIAMENTOR Connector (v type)female

DIAMENTOR Connector (A type)male

DIAMENTOR Connector (a type)female

DIAMENTOR Connector (F type)male

DIAMENTOR Connector (f type)femalePTW can provide adaptation cables for all combinations of detectors shown above. In practice not all combinations makesense and are dangerous respectively. The reason for this is among other things, that the different connecting systems
have diverse uses for the outer shielding of the cable. While some connecting systems use the cable’s outer shielding forthe high voltage supply of the ionization chamber, other systems use it for the grounding of the chamber and connect itto the chamber housing. Unsuitable adaptation cables may result in improper grounding of the chamber and in the worst
case in the risk of an electric shock. Touchable parts of the chamber may conduct high voltage.
Adaptations between Triax PTW (M type) and BNC with Banana (B type) are problem-free. Likewise are adaptations
between BNT (N type) and TNC (W type) systems in general unproblematic. The same applies to our different DIAMENTOR
connecting systems. For all other combinations of connecting systems we strongly dissuade from using adaptation cables.
Any use of such adaptation cables is definitely out of the intended use and left to the user’s responsibility.
As each manufacturer has its own manufacturing tolerances for connectors, PTW cannot guarantee that its TNC connectors fit to connectors supplied by other manufacturers.
The following table shows the possible connector
combinations used in radiation therapy.

Connector Type

Outer Diameter

N, n

15 mm, 14 mm

W, w

16 mm, 14 mm

✘

M, m

25 mm, 24 mm

✓

✓

B, b

18 mm, 18 mm

L, l

9 mm, 9 mm

✓

✓

V, v

15 mm, 16 mm

A, a

14 mm, 14 mm

F, f

18 mm, 19 mm

N, n

W, w

M, m

B, b

N, n

✓

✓

✘

✘

W, w

✓

✓

✘

M, m

✘

✘

✘

✘

B, b

✓ Suitable adaptation cable✘ Unsuitable adaptation cable

Approximate outer connector diameters:69

Quick View

Guide to PTW Detectors
This guide gives a review of the complete range of PTW radiation detectors arranged in the order of their scope. Someof the detectors are suitable for various applications. Especially the ion chambers designed for absolute dosimetry inradiotherapy can also be used for therapy beam analysis. All ionization chambers are supplied with vented sensitive
volumes, open to the surrounding, except the sealed 0.1 cm3 chamber models 23322 and 23323. The type numbersin brackets represent former chamber types with identical specification. Radiation detectors which are integrated
components of radiation measuring systems such as LA48 Linear Array, DIAMENTOR or CURIEMENTOR, are not listed
in this guide.

Radiation Therapy
30010(30001)

0.6 cm3
Farmer Chamber
PMMA/AlThimble chamber with acrylic wall and Al electrode for measuring high-energy photon and electron radiation in air andphantom material. BNT, TNC or M connector

page

30011
(30002)

0.6 cm3
Farmer Chamber
Graphite/Graphite

Thimble chamber with graphite wall and graphite electrodefor measuring high-energy photon and electron radiation in airand phantom material. BNT or TNC connector

page

30012
(30004)

0.6 cm3
Farmer Chamber
Graphite/Al

Thimble chamber with graphite wall and Al electrode formeasuring high-energy photon and electron radiation in airand phantom material. BNT or TNC connector

page

30013
(30006)

0.6 cm3
Farmer Chamber
Waterproof

Waterproof chamber with acrylic wall and Al electrode formeasuring high-energy photon and electron radiation in air,water and phantom material. BNT, TNC or M connector

page

31010
(31002)0.125 cm3
Semiflex Chamber

Waterproof thimble chamber for measuring high-energy photon pageand electron radiation in air, water and phantom material.
14
BNT, TNC or M connector

31013(31003)0.3 cm3
Semiflex Chamber

Waterproof thimble chamber for measuring high-energy photon pageand electron radiation in air, water and phantom material.
15
BNT, TNC or M connector

30016(23332)0.3 cm3
Rigid Stem Chamber

Thimble chamber with 25 cm rigid stem for measuring highenergy photon and electron radiation in air and phantom
material. BNT, TNC or M connector

page

30015
(23331)

1 cm3
Rigid Stem Chamber

Thimble chamber with 25 cm rigid stem for measuring highenergy photon and electron radiation in air and phantom
material. BNT, TNC or M connector

page

34045

0.02 cm3
Advanced Markus
Electron Chamber

Improved plane parallel chamber with thin membrane for meas- pageuring high-energy electron radiation in water and phantom
18material. BNT, TNC or M connector

23343

0.055 cm3
Markus Electron
ChamberClassic plane parallel chamber with thin membrane for measur- pageing high-energy electron radiation in water and phantom mate19
rial. BNT, TNC or M connector

34001

0.35 cm3
Precision plane parallel chamber for absolute dosimetry of
Roos Electron Chamber high-energy electron radiation in water and phantom material.
BNT, TNC or M connector

page

10.5 cm3
Bragg Peak Chamber

Waterproof plane parallel chamber for measuring the exact
location of the Bragg peak in proton beams.
BNT, TNC or M connector

page

2.5 cm3
Bragg Peak Chamber

Waterproof plane parallel chamber for measuring the exact
loacation of the Bragg peak in horizontal proton beams.
BNT, TNC or M connector

page

31014

0.015 cm3
PinPoint Chamber

Ultra small-sized waterproof therapy chamber for dosmimetry in pagehigh-energy photon beams.
23
BNT, TNC or M connector

31015

0.03 cm3
PinPoint Chamber

Small-sized waterproof therapy chamber for dosmimetry inhigh-energy photon beams.
BNT, TNC or M connector

34070

34073

70

10

11

12

13

16

17

20

21

22

page
24

Quick View

31016

0.016 cm3
PinPoint 3D Chamber

Ultra small-sized waterproof therapy chamber with 3D
characteristics for dosmimetry in high-energy photon beams.
BNT, TNC or M connector

page

microDiamond

Waterproof small volume diamond detector for dosimetry inhigh-energy photon and electron beams.
BNT, TNC or M connector

page

Dosimetry Diode P
for Photons

Waterproof p-type Si diode detector for dosimetry inhigh-energy photon beams.
BNT, TNC or M connector

page

Dosimetry Diode E
for Electrons andPhotons

Waterproof p-type Si diode detector for dosimetry inhigh-energy electron and photon beams.
BNT, TNC or M connector

page

Dosimetry Diode SRS
for Photons

Waterproof p-type Si diode detector for dosimetry in photon
beams. Typical use is for measurements for stereotactic radio
surgery. BNT, TNC or M connector

page

Dosimetry Diode PR
for Protons

Waterproof p-type Si diode detector for dosimetry inhigh-energy proton beams.
BNT, TNC or M connector

page

0.02 cm3
Soft X-ray Chamber

Plane parallel chamber with thin membrane for measuring
therapeutic X-ray beams between 10 and 100 kV in air andphantom material. BNT, TNC or M connector

page

0.2 cm3
Soft X-ray Chamber

Plane parallel chamber with thin membrane for measuring
therapeutic X-ray beams between 10 and 100 kV in air andphantom material. BNT, TNC or M connector

page

34013

0.005 cm3
Soft X-ray Chamber

Plane parallel chamber with thin membrane for measuring small page
size therapeutic X-ray beams between 15 and 50 kV in air and33
phantom material. BNT, TNC or M connector

33005

SOURCECHECK 4π
Well-type Chamber

Well-type ionization chamber for source strength
measurements in brachytherapy.
BNT, TNC or M connector

page

3.14 cm3
CT Chamber

Vented cylindrical chamber for dose length productmeasurements in computed tomography.
BNT, TNC, M or L connector

page

9.3 cm3
CT Chamber

Vented cylindrical chamber for dose length productmeasurements in computed tomography.
BNT, TNC, M or L connectorpage

75 cm3
SFD Diagnostic
Chamber

Shadow-free plane parallel chamber for absolute dosimetry
in diagnostic radiology.
BNT, TNC, M or L connector

page

6 cm3
SFD Mammo Chamber

Shadow-free plane parallel chamber for absolute dosimetry
in diagnostic radiology and mammography.
BNT, TNC, M or L connector

page

R/F/D Detector
MAM Detector

Semiconductor detectors for diagnostic X-rays.
TNC or L connector

page

60019

60016

60017

60018

60020

23342

23344

25

26

27

28

29

30

31

32

34

Diagnostic Radiology
30009

30017

34060

34069

60004
60005

38

39

40

41

42

71

Quick View

Health Physics
T34031
T320043 Liter
Cylindrical Chamber

Cylindrical poly ethylene chamber for stationary low level
gamma radiation measurement above 80 keV.
Special connectors for signal and HV

page

T7262

50 Liter
Cylindrical Chamber

Cylindrical pressurized steel chamber for stationary lowest
level gamma radiation measurement above 80 keV. Special
connectors for signal and HV

page

1 Liter
Spherical Chamber

Spherical chamber, 140 mm diameter, for low level gamma
radiation protection measurements in the energy range of
45 keV to 50 MeV. BNT, TNC or M connector

page

10 Liter
Spherical Chamber

Spherical chamber, 270 mm diameter, for lowest level gamma
radiation protection measurements in the energy range of
45 keV to 50 MeV. BNT, TNC or M connector

page

50 cm3Spherical Chamber
PS-50

Spherical chamber, 53 mm diameter, for primary standard
radiation protection measurements in 60Co and 137Cs beams.
BNT connector

page

10 cm3Spherical Chamber
PS-10

Spherical chamber, 34 mm diameter, for primary standard
radiation protection measurements in 60Co and 137Cs beams.
BNT connector

page

30 cm3Spherical Chamber

Spherical chamber, 22 mm diameter, for gamma radiation
protection measurements in the energy range of 25 keV
to 1.3 MeV. BNT, TNC or M connector

page

30 cm3
Cylindrical Chamber

Cylindrical reference chamber, 31 mm diameter, for gamma
radiation protection measurements in the energy range of
30 keV to 50 MeV. BNT, TNC or M connector

page

34035
L981937
L981938

Hp(10) Secondary
Standard Chamber

Plane parallel reference chamber embedded in an acrylic slab
phantom for direct measurement of Personal Dose Equivalent
Hp(10). M or BNC/banana connector

page

TN34014
TW34014
TM786

Transmission
Monitor Chambers for
Calibration Benches

Circular transmission chambers of 155 mm resp. 148 mm
sensitive diameter for radiation monitoring of calibration
benches. BNT, TNC, M or BNC/banana connector

pageTM7862

Transmission
Monitor Chamber for
X-ray Therapy Units

Circular transmission chamber of 96.5 mm sensitive diameter for page
radiation monitoring of X-ray therapy units.
55
M or BNC/banana connector

T23392

Böhm Extrapolation
Chamber

Precision extrapolation chamber with adjustable depth of thesensitive volume between 0.5 mm and 10.5 mm for dose
measurements of Beta and soft X-rays. BNC sockets

32002

32003

32007S

32008S

32005

23361

72

46

47

48

49

50

50

51

52

53

54

page
56

Codes of PracticeCodes of PracticeAbsorbed Dose Determinationin Photon and High Energy
Electron Beams
Based on Standards ofAbsorbed Dose to Water
1 Introduction

74

2 General Instructions
2.1 Corrected reading M
2.2 Measuring phantoms
2.3 Chamber positioning
2.4 Air density
2.5 Ion recombination
2.6 Polarity effect
2.7 Humidity

75
75
75
77
77
79
79

3 Kilovoltage X-Ray Beams
3.1 10 kV to 100 kV
3.2 100 kV to 300 kV

80
80

4 High Energy Photon Beams
4.1 IAEA TRS 398
4.2 AAPM TG-51
4.3 DIN 6800-2

82
84
86

5 High Energy Electron Beams
5.1 IAEA TRS 398
5.2 AAPM TG-51
5.3 DIN 6800-2

88
90
91

6 Measurements in Acrylic Phantoms

Disclaimer

6.1 General
6.2 High energy photons
6.3 High energy electrons

94
94
94

7 References

95

Appendix A:
Summary of PTW Chamber Data

97

Although the information in this document has
been carefully assembled, PTW-Freiburg does notguarantee that this document is free of errors.
PTW-Freiburg shall not be liable in any way for any
consequence of using this document.
73

Absorbed Dose Determination in Photon and High Energy Electron Beams
Introduction

1 Introduction
This document constitutes an excerpt of procedures
and data from various dosimetry protocols for thedetermination of absorbed dose to water using ionization chambers. As most modern dosimetry protocols (e.g. IAEA, AAPM, DIN) refer to ionizationchambers calibrated in absorbed dose to water, thisdocument does not describe dose determination
with ionization chambers having other calibration
factors.1
The chapters referring to high energy radiation describe the formalisms outlined in IAEA TRS 398,
AAPM TG-51 and DIN 6800-2 as these dosimetry
protocols are widely used, see references [IAEA
398], [AAPM 51] and [DIN 6800-2]. The chapter
referring to kilovoltage X-ray beams describes only
the formalism outlined in the DIN standards as
IAEA TRS 398 differs only slightly from DIN, andAAPM TG-51 does not address this energy range.

NOTE
The terms 'Markus Chamber', 'Advanced Markus
Chamber' and 'Roos Chamber' are the propriety of
PTW-Freiburg. The published data specific to thesechambers are not valid for chambers manufactured
by other companies, even if they are sold as'Markus' or 'Roos' type chambers.

A summary of PTW chamber data is given in
Appendix A.

Although this document provides the reader with aconcise overview of formulae and factors it shall not
replace pertinent protocols and publications, nor is
it intended to give all of the details that are important for accurate dosimetry. Also, the procedures
outlined in this document are not the only ones
described in the referenced literature, they constitute only one of several possibilities for absorbed
dose determination.
The present document is limited to the use of open (vented) ionization chambers
 the use of plane-parallel chambers in case of
low energy X-ray beams
 the use of cylindrical chambers in case of medium energy X-ray beams
 PTW chambers if factors are given that dependon the design of the ionization chamber.

1

Document D560.210.00 refers to chambers calibratedin Air Kerma, Absorbed Dose to Air, and Exposure.

74

74

D560.210.01/10

Absorbed Dose Determination in Photon and High Energy Electron Beams
General Instructions

2 General Instructions
2.1 Corrected reading M

2.3 Chamber positioning

All formulae in this document used for the determination of absorbed dose to water D w refer to adosemeter reading M which is corrected for the
influence quantities given in chapters 2.4 - 2.7. The
reader must compute the corrected reading M fromthe uncorrected reading M uncorr and the reading
without irradiation M 0 by

2.3.1 General rulesM  (M uncorr  M 0 )  k elec  k TP  k S  k pol  k h(2-1)

The correction factor k elec corresponds to the calibration factor of the electrometer if the electrometerreadout is in terms of charge or current [IAEA 398,
AAPM 51]. If the electrometer and the ionizationchamber are calibrated together and the readout isin terms of Gy or Gy/s, a value of unity is to be used
for k elec .
The correction factors k TP , k S , k pol and k h aredescribed in chapters 2.4 - 2.7. For absorbed dose
determination, additional factors are to be applied tothe corrected reading M as described in chapters
3 - 6.

2.2 Measuring phantoms
This document assumes that all measurements are
made in a water phantom, except for chapter 3.1
where the measurements are made at the surface
of an acrylic (PMMA) phantom. If measurements
are nevertheless made in other than water phantoms, the measures described in chapter 6 are to
be taken. It should be noted, however, that mostdosimetry protocols prescribe measurements inwater only.

The dosemeter reading is obtained by positioning
the ionization chamber at the point of interest in thephantom. Depending on the dosimetry protocol andradiation quality, either the effective point of measurement or the reference point of the ionizationchamber is positioned at the point of interest. This
document states the correct positioning method ineach of the related chapters.
The effective point of measurement is defined as a point on the axis of a cylindrical chamber incase of photon beams with energy < 1.33 MeV
 a point shifted by 0.5 r from the axis of a cylindrical chamber towards the focus2 in case ofhigh energy photon and electron beams ( r is
the inner radius of the measuring chamber volume) [IAEA 398, DIN 6800-2]
 a point at the center of the inner side of the entrance window of a plane-parallel chamber, independent of radiation quality. Care must be
taken to scale the thickness of the entrance window to water-equivalent thickness.
The reference point is defined as a point on the central axis of a cylindrical chamber as stated by the manufacturer
 a point at the center of the inner side of the entrance window of a plane-parallel chamber.

2

D560.210.01/10

To measure dose at a focus distance of x cm, the axisof the cylindrical chamber must be positioned at a focus
distance of x cm + 0.5 r , i. e. the chamber must be
shifted away from the focus, i.e. downstream.

75

75

Absorbed Dose Determination in Photon and High Energy Electron Beams
General Instructions

2.3.2 Plane-parallel chambers
Plane-parallel chambers usually have entrance
windows which are not exactly water-equivalent.
For the correct positioning of a plane-parallel
chamber in water, the geometrical thickness d p ofthe entrance window must be scaled to equivalentwater thickness d w . The effective point of measurement is then located behind the water-equivalent
thickness d w of the entrance window.
The scaling of the geometrical thickness (e.g. plastic thickness) d p to water equivalent thickness d w
is done by [IAEA 398]

dw  d p 

ρp

(2-1)

ρw

where ρp and ρw are the densities of the entrance
window and water, respectively3. Using the area
density σ p and ρw  1 g / cm 3 , equation (2-1) canbe written as

dw 

σp
ρw



σp
1 g/cm 3(2-2)

The area density σ p of PTW plane-parallel chambers is given in Appendix A. For instance, the water-equivalent thickness of the entrance window of a
Roos chamber type 34001 ( σ p  132 mg / cm 2 ) is

 according to (2-2) the water-equivalent thicknessof the entrance window is d w  1.06 mm , i.e.
the effective point of measurement is locatedbehind a 'water layer' of 1.06 mm from thechamber surface
 the measuring depth in water shall bez  10 mm . As the entrance window contributes
1.06 mm , the chamber surface has tobe positioned at a water depth of
10 mm  1.06 mm  8.94 mm .
2.3.3 The TRUFIX system

The task of positioning various types of ionizationchambers precisely in their effective point of measurement can be quite challenging. The patented
TRUFIX system (see Figure 1) facilitates this task
considerably. TRUFIX can be used on automated
PTW water phantoms (MP2, MP3 etc.) in connection with most PTW therapy detectors. A plastic tip
lets you easily locate the water surface where thecoordinate system is set to (0,0,0). Then the plastic
tip is replaced by a holding device specific to eachdetector type, and the effective point of measurement is automatically placed at the tip's earlier position. The radius of cylindrical chambers, the waterequivalent window thickness of plane-parallel
chamber windows and the chamber centers areautomatically accounted for.

d w  1.32 mm . The entrance window of the Ad-

vanced Markus chamber (including protection cap, (σ p  106 mg / cm 2 ) has a water-equivalent thickness of d w  1.06 mm .
ExampleHow to position the effective point of measurementof an Advanced Markus chamber with protection
cap at a measuring depth of z  10 mm in water: according to Appendix A, the area density of theentrance window, including the protection cap
and air gap, is σ p  106 mg / cm 2

3

Figure 1: The TRUFIX chamber positioning system.

DIN 6800-2 suggests to use the electron volume densities of the materials rather than the physical densities.
The difference is neglected in this document.

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D560.210.01/10

Absorbed Dose Determination in Photon and High Energy Electron Beams
General Instructions

2.4 Air density

kp and km must not be mixed up with correction

factors described in other chapters of this document.

2.4.1 The T&P method

Open (vented) ionization chambers must be corrected for air density according to [IAEA 398]
k TP 

P0  273.2  T 
P  273.2  T0 

(2-3)

T and P are the temperature and pressure in themeasuring environment, the reference values are
P0  101 .3 kPa and T0  20 o C . Note that in somecountries the reference temperature given in thecalibration certificate is 22 o C instead of 20 o C .
AAPM TG-51 uses a value of 22 o C as reference
and a value of P0  101 .33 kPa for the reference
pressure.

Care must be taken to ensure the use of correct
values for the barometric pressure P existing in themeasuring environment. Details can be found in theliterature [Christ 2004].
2.4.2 The check source method

Instead of using (2-3) measurements in a radioactive check source can be made. The temperatureof the check source and the ionization chamber
must be the same as the temperature of the phantom in which the dose measurements are performed. The reference value k protocol of the checksource reading is given in the calibration certificate
for a given date and for reference conditions (e.g.
101 .3 kPa , 20 o C ). The reader must correct thereference value k protocol for the decay of the radioactive material. Then an actual check source reading k measured is taken and the correction factor for
air density is determined fromk TP 

kprotocol(2-4)

kmeasured

NOTE
The results of (2-3) and (2-4) normally coincide
better than 0.5 % . If not, the reason must be found.
NOTE
In the calibration certificates of PTW-Freiburg thereference reading k protocol is described as kp , thecheck reading
D560.210.01/10

kmeasuredis described as

km .

2.5 Ion recombination
2.5.1 The two-voltage method

Correction factors for insufficient charge collectionin the measuring volume of the ionization chamber
can be measured using the two-voltage method[IAEA 398, AAPM 51]. They depend on the geometry of the ionization chamber and on the dose rateor dose per pulse, respectively.
For pulsed or pulsed-scanned radiation the correction factor k S can be determined from [IAEA 398]kS 

M1 / M 2  1
1
V1 / V2  1(2-5)

where M1 and M 2 are the readings at two voltages
V1 and V2 . V1 is the normally used voltage, and V2
is a voltage reduced by a factor of at least 3. Formula (2-5) is valid for k S  1.03 . If k S  1.03 referto chapter 2.5.2.
For continuous radiation k S is taken from [IAEA
398]
kS 

V1 / V2 2  1
V1 / V2 2  M1 / M 2 (2-6)

Formula (2-5) assumes a linear relationship between 1 / M and 1 / V , formula (2-6) a linear relationship between 1/ M and 1/ V 2 . New chambers
should be tested in accordance with the following
chapter.
2.5.2 Jaffé diagrams

A Jaffé diagram represents the inverse reading
1 / M of an ionization chamber as a function of theinverse voltage 1 / V ( 1/ V 2 in case of continuousradiation). The reading M is corrected for polarity
effect, i.e. M is the mean value of M  and M  ,see chapter 2.6. Figure 2 shows a Jaffé diagram forpulsed radiation with the axes normalized to theusual voltage V1 and the corresponding reading M1
.

77

77

Absorbed Dose Determination in Photon and High Energy Electron Beams
General Instructions

1,030

The two-voltage method (see chapter 2.5.1) can beapplied only if both voltages V1 and V2 are within

1,025
1,020

the linear range of the Jaffé diagram. If this is not
the case, the ionization chamber should be operated at the highest voltage of the linear range of the
Jaffé diagram, and the correction factor k S should

M1/M

1,015
1,010
1,005
1,000
0,995
0,990
0,985

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

4,5

V1/V

Figure 2:Jaffé diagram of a typical Farmer chamberusually operated at V1  400 V . The regression line to the linear part intersects
the M1 /M axis at 0.992 resulting in a correction factor k S  1/0.992  1.008 . The
dose per pulse was 0.974 mGy .

The useful range for the chamber voltage should be
limited to the linear part of the Jaffé diagram. This
document suggests to measure Jaffé diagrams at
the lowest and at the highest dose per pulse ordose rate for each radiation quality, and to determine the linear range for the used ionization chamber from these diagrams.

be determined by extrapolating the linear part of the
Jaffé diagram to an infinite voltage ( 1/ V  0 ). It
should be noted that operating an ionization chamber at a voltage other than stated in the calibration
certificate may cause an error as the calibration
factor sometimes depends on the applied voltage.
2.5.3 The DPP method

If the dose per pulse (DPP) of the accelerator at the
point of measurement is known, the correction factor can be calculated by [DIN 6800-2]
kS  1γ δ  DP
U U(2-7)

DP is the absorbed dose to water per accelerator
pulse, expressed in mGy , U is the chamber voltage in V , and the coefficients γ and δ are listed

in Table 1 [Bruggmoser 2007]. Formula (2-7) is only
valid if the frequency of the accelerator pulses issmaller than the reciprocal of the ion collection time.

Dose per pulse Chamber voltage
V
mGy

Chamber typeγV

δV / mGy

PTW 30006/30013 Farmer

0.01

3.44

0.15 – 0.35
> 0.35 – 42

100 – 300
300 – 400

PTW 23332/30016 0.3 cm³
Rigid Stem

0.13

1.05

0.15 – 0.5> 0.5 – 5.5

100 – 250
250 – 400

PTW 31002/31010 0.125 cm³
Semiflex

0.38

2.40

0.15 – 0.6> 0.6 – 5.5

100 – 300
300 – 400

PTW 23331/30015 1 cm³
Rigid Stem

0.00

5.68

0.25 – 1.5

100 – 400

PTW 34001 Roos

0.06

1.69

0.15 – 0.5> 0.5 – 42

50 – 200
200 – 300

PTW 34045 Advanced Markus

0.43

0.49

0.25 – 1.0> 1.0 – 5.5

50 – 200
200 – 300

PTW 23343 Markus

0.32

1.99

0.15 – 0.55
> 0.55 – 3.0

100 – 250
250 – 300

Table 1: Coefficients γ and δ for formula (2-7), applicable within the stated dose per pulse and voltage ranges, according to [Bruggmoser 2007, Bruggmoser 2008].

78

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Absorbed Dose Determination in Photon and High Energy Electron Beams
General Instructions

2.6 Polarity effect
The polarity effect depends on the radiation beam
quality Q . The correction factor can be determinedby [IAEA 398, DIN 6800-2]
kpol=

M +M   / M  Q
M +M   / M  Co(2-8)

M  = positive reading obtained with the usual
polarityM  = positive reading obtained with the opposite
polarity

The index Co refers to the readings obtained in a
Co beam during calibration. This value is normally60
not given in the calibration certificate. If Co isavailable the user should measure this value, if not,this value should be requested from the calibrationlaboratory [IAEA 398, AAPM 51] or should bemeasured with the lowest available photon energy[DIN 6800-2]. If the effect of this value is smaller
than 0.3 % for 6 MV photon beams (or lower energy), the denominator in formula 2-8 can be set to 2,otherwise it must be taken into account [AAPM 51].
60

2.7 Humidity
A correction factor for humidity has to be applied60
only if the Co calibration factor refers to dry air[IAEA 398]:(2-9)

kh  0.997
60

Usually the Co calibration factor refers to a relative humidity of 50 % ; in this case kh is taken as
1.000.

D560.210.01/10

79

79

Absorbed Dose Determination in Photon and High Energy Electron Beams
Kilovoltage X-Ray Beams

3 Kilovoltage X-Ray Beams
3.1 10 kV to 100 kV(3-1)

Dw  k Q  N w  M
Dw=absorbed dose to water [DIN 6809-4]

kQ=

energy dependent correction factor, given in the calibration certificate for several
radiation qualities. PTW offers calibrations at 15, 30, 50, and 70 kVNw=calibration factor for absorbed dose towater for the reference radiation quality
stated in the calibration certificateM=corrected reading of the dosemeter, seechapter 2.1. Measurements are to bemade at the surface of an acrylic (PMMA)
phantom. For measurements at otherdepths, water-equivalent material is to be
added

Influence Quantity

Reference Condition

Phantom material

PMMA

Chamberplane-parallel, Type PTW
23342, 23344, or 34013

Depth

phantom surface

Chamber positioning

outer surface of entrance
windowSSD

as stated in calibration certificate

Field size

as stated in calibration certificate, or 3 cm x 3 cm at themeasuring plane

NOTE
DIN 6809-4 suggests the use of a 0.1 mm waterequivalent plastic foil in front of the ionizationchamber when measuring above 50 kV. This foil
should provide adequate build-up and eliminate low
energy electrons scattered upstream. IAEA TRS
398 suggests total material thicknesses (build-up
foils plus entrance window) depending upon radiation quality (IAEA Table 24. Foil thicknesses should

80

80

read µm). Ideally, the chamber and the build-up
foils should be calibrated together, but this calibration is not available from PTW. If the user decides
to use build-up foils, he should determine a correction factor for each beam geometry and radiation
quality used.

3.2 100 kV to 300 kV(3-2)

Dw  k F  k Q  N w  M
Dw=absorbed dose to water [DIN 6809-5]

kF=

correction factor for field sizes other than
10 cm x 10 cm (or circular fields of 10 cm
in diameter), see Table 3

kQ=

energy dependent correction factor, given in the calibration certificate for several
radiation qualities. PTW offers calibra60
tions at 100, 140, 200, 280 kV, and Co.
If no calibration data specific to thechamber is available, use the values
given in Table 2. This will increase theuncertainty of the measured valueNw=calibration factor for absorbed dose to60
water for Co

M=

corrected reading of the dosemeter, seechapter 2.1

Influence Quantity

Reference Condition

Phantom material

water

Chambercylindrical

Depth

5 cm

Chamber positioning

chamber axis

SSD

100 cmField size

as stated in calibration certificate, or 10 cm x 10 cm at
the phantom surface

D560.210.01/10

Absorbed Dose Determination in Photon and High Energy Electron Beams
Kilovoltage X-Ray Beams

Radiation Quality(Gen. Voltage, HVL)

PTW 23331,
30015
1.0 cm³

PTW 23332,
30016
0.3 cm³

PTW 31013,
31003
0.3 cm³

PTW 31010,
31002
0.125 cm³

Rigid Stem

Rigid Stem

Semiflex

Semiflex

T100 (0.17 mm Cu)
T120 (0.28 mm Cu)
T140 (0.50 mm Cu)
T150 (0.85 mm Cu)
T200 (1.65 mm Cu)
T250 (2.5 mm Cu)
T280 (3.4 mm Cu)

1.025
1.017
1.008
1.000
0.998
0.998
0.996

1.045
1.002
0.996

1.025
0.999
0.994

1.025
0.999
0.994

60

1.000

1.000

1.000

1.000

Co

Table 2: k Q for the reference depth of 5 cm and the reference field size of 10 cm x 10 cm [DIN 6809-5]. The
values for PTW 31002/31010 have been added by PTW-Freiburg. The values for the new chamber
types PTW 30015 and PTW 30016 should be similar to those given in the DIN table for PTW 23331
and PTW 23332, respectively.

Radiation Quality

T100
T140
T200
T280

PTW 23331, 30015
1.0 cm³ Rigid Stem
5 cm x 5 cm
15 cm x 15 cm

1.02
1.03
1.04
1.03

1.00
1.00
0.99
0.99

PTW 23332, 30016
0.3 cm³ Rigid Stem
5 cm x 5 cm
15 cm x 15 cm

1.00
1.02
1.03
1.02

1.00
1.00
1.00
0.99

Table 3: Field size dependent correction factor kF at the reference depth of 5 cm [DIN 6800-9]. The values forthe new chamber types PTW 30015 and PTW 30016 should be similar to those given in the DIN tablefor PTW 23331 and PTW 23332, respectively.

D560.210.01/10

81

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Photon Beams

4 High Energy Photon Beams
4.1 IAEA TRS 398(4-1)

Dw  k Q  N w  M

NOTE
In case TPR 20,10 values are not available, they canbe determined from [IAEA 398]
TPR20,10  1.2661  PDD20,10  0.0595

Dw=

absorbed dose to water

kQ

=

Nw

=

energy dependent correction factor, see
Table 4calibration factor for absorbed dose to60
water for Co

M=

corrected reading of the dosemeter, seechapter 2.1

Influence Quantity

Reference Condition

Phantom material

water

Chambercylindrical

Depth

10 cm (or 5 cm) for

where PDD20,10 is the ratio of the percent depth
doses at 20 cm and 10 cm depth, respectively. The
PDD values must be measured at SSD  100 cm
with a field size of 10 cm x 10 cm at the phantom
surface.
For beam quality specification measurements with acylindrical chamber, the chamber axis should bepositioned at the measuring depth. It is allowed touse a plane-parallel chamber to determine beam
quality.

TPR 20,10  0.7

10 cm forTPR 20,10  0.7

Chamber positioning

chamber axis

SSD / SDD

100 cmField size

10 cm x 10 cm
SSD setup: field size defined at surface
SDD setup: field size defined in detector plane

The tissue phantom ratio TPR 20,10 is measured foreach nominal accelerating voltage. TPR 20,10 is defined as the ratio M 20 / M 10 of two ionization readings of a dosemeter at different depths. M 20 isobtained at 20 cm depth of water, M 10 at 10 cm
depth of water at a fixed source-detector-distance
SDD = 100 cm and a field size of 10 cm x 10 cm at
the depth of measurement.

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High Energy Photon Beams

PhotonBeam
Quality

PTW
23331

PTW
23332

TPR 20 ,10

1.0 cm³
Rigid
Stem

0.3 cm³
Rigid
Stem

0.50
0.53
0.56
0.59
0.62
0.65
0.68
0.70
0.72
0.74
0.76
0.78
0.80
0.82
0.84

1.004
1.003
1.000
0.999
0.997
0.993
0.990
0.988
0.985
0.982
0.978
0.971
0.964
0.956
0.945

1.004
1.003
1.001
0.999
0.997
0.994
0.990
0.988
0.984
0.980
0.976
0.968
0.961
0.954
0.943

PTW
23333/
30001/
30010
Farmer

PTW
30002/
30011

PTW
30004/
30012

PTW
30006/
30013

PTW
31002/
31010

PTW
31003/
31013

FarmerFarmerFarmer0.125 cm³
Semiflex

0.3 cm³
Semiflex

1.004
1.003
1.001
0.999
0.997
0.994
0.990
0.988
0.985
0.981
0.976
0.969
0.962
0.955
0.943

1.006
1.004
1.001
0.999
0.997
0.994
0.992
0.990
0.987
0.984
0.980
0.973
0.967
0.959
0.948

1.006
1.005
1.002
1.000
0.999
0.996
0.994
0.992
0.989
0.986
0.982
0.976
0.969
0.962
0.950

1.002
1.002
1.000
0.999
0.997
0.994
0.990
0.988
0.984
0.980
0.975
0.968
0.960
0.952
0.940

1.003
1.002
1.000
0.999
0.997
0.994
0.990
0.988
0.984
0.980
0.975
0.968
0.960
0.952
0.940

1.003
1.002
1.000
0.999
0.997
0.994
0.990
0.988
0.984
0.980
0.975
0.968
0.960
0.952
0.940

PTW
31014/
31015/
31016
PinPoint

1.004
1.003
1.001
0.999
0.998
0.995
0.992
0.989
0.985
0.980
0.975
0.967
0.959
0.952
0.941

Table 4: Typical k Q values for PTW cylindrical chambers IAEA 398, [IAEA 398/2].
60
For Co beams k Q is 1.000.
The PinPoint chambers types 31015 and 31016 have been added by PTW-Freiburg.

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Photon Beams

4.2 AAPM TG-51

When measuring a depth dose curve for the determination of %dd ( 10 )x a lead foil should be used
(4-2)

Dw  k Q  N w  M
Dw=absorbed dose to water

kQ=

energy dependent correction factor, see
Tables 5a, 5b. The values can be used
for both flattened and flattening filter freebeams
calibration factor for absorbed dose to60
water for Co

Nw

=

M

=

corrected reading of the dosemeter, seechapter 2.1. In non-uniform beams, e.g.
FFF beams, the reading must be averaged over the dimensions of the active
volume of the ionization chamber

Influence Quantity

Reference Condition

Phantom material

water

Chambercylindrical, PTW chambers
as listed in Table 5a

Depth

10 cm

Chamber positioning

chamber axis

SSD/SDD

100 cmField size

10 cm x 10 cm
SSD setup: field size
defined at surface
SDD setup: field size
defined in detector plane

The beam quality specifier %dd ( 10 )x is the percentage depth dose at 10 cm depth in a water
phantom due to photons only. %dd ( 10 )x is definedat SSD  100 cm for a field size of 10 cm x 10 cm
at the phantom surface.

8484i) at energies about 10 MV and above if highest
precision is desiredii) for measurements of flattening filter free (FFF)
beams at all energies.
The lead foil should be 1 mm in thickness ( 20 %)and it should be placed (50  5) cm or, if this is
impossible, (30  1) cm above the phantom surface.
The beam quality specifier is obtained from thecorresponding value %dd (10 )Pb by one of the following formulae
lead foil at (50  5) cm and %dd (10 )Pb  73 %%dd (10 ) x  (0.8905  0.0015  %dd (10 )Pb )  %dd (10 )Pb(4-3)
lead foil at (30  1) cm and %dd (10 )Pb  71 %%dd (10 ) x  (0 .8116  0 .00264  %dd (10 )Pb )  %dd (10 )Pb(4-4)
If %dd (10 )Pb is below the above thresholds,%dd (10 ) x equals %dd (10 )Pb .
NOTEThe lead foil is used for beam quality specification
only. Remove the lead foil for dose measurements.

For beam quality specification measurements with acylindrical chamber, the chamber axis must be
shifted downstream by 0.6 r , where r is the inner
radius of the measuring volume. It is allowed to use
a plane-parallel chamber to determine beam
quality.

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Photon Beams%dd ( 10 )x

PTW
30001/
30006
Farmer

PTW
30002
Farmer

PTW
30004
Farmer

PTW
30010
FarmerPTW
30011
Farmer

PTW
30012
Farmer

PTW
30013
Waterproof
Farmer

PTW
31003/
31013
Semiflex

58.0
63.0
66.0
71.0
81.0
93.0

1.000
0.996
0.992
0.984
0.967
0.945

1.000
0.997
0.994
0.987
0.970
0.948

1.000
0.998
0.995
0.988
0.973
0.952

1.000
0.997
0.993
0.986
0.968

1.000
0.997
0.994
0.986
0.969

1.000
0.998
0.995
0.988
0.971

1.000
0.996
0.992
0.985
0.967

1.000
0.997
0.993
0.986
0.967

Photon Beam
Quality

60

Table 5a: Typical k Q values for PTW cylindrical chambers AAPM 51, [AAPM 51/2]. For Co beams k Q
is 1.000. [AAPM 51/2] does not recommend the 0.125 cm³ Semiflex chambers PTW 31002 and31010 as reference class chambers. PTW suggests the use of the same k Q values as for the
0.3 cm³ Semiflex chamber PTW 31013.

Chamber TypePTW 30010 Farmer
PTW 30011 Farmer
PTW 30012 Farmer
PTW 30013 Waterproof Farmer
PTW 31003/31013 Semiflex

A

B

C

1.00930.9676
0.95370.9652
0.9725

0.926
2.061
2.440
2.141
1.957

-1.771-2.528-2.750-2.623-2.498

Table 5b: Fit parameters for k Q values for PTW cylindrical chambers [AAPM 51/2]. k Q is obtained from thefollowing formula which holds for beam specifiers between 63 and 86:
k Q  A  B  10  3  % dd (10 ) x  C  10  5  (% dd (10 ) x ) 2

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Photon Beams

4.3 DIN 6800-2(4-5)

Dw  k r  k Q  N w  M
Dw=absorbed dose to waterkr=

1 + 0.03 r replacement correction factor( r is the inner radius of the measuring
volume of a cylindrical chamber, given incm). kr is not applicable for planeparallel chambers). See Table 7
energy dependent correction factor, see
Table 6calibration factor for absorbed dose to60
water for Co

kQ

=

Nw

=

M

=

corrected reading of the dosemeter, seechapter 2.1

Influence Quantity

Reference Condition

Phantom material

water

ChambercylindricalDepth

5 cm for Co
10 cm for photons

Chamber positioning

effective point of measurement, see chapter 2.3

SSD

95 cm for Co
100 cm for photons

Field size

10 cm x 10 cm at 5 cm
60
depth for Co
10 cm x 10 cm at phantom
surface for photons

NOTE
In case M10 and M 20 values are not available, Q
can be determined from DIN 6800-2

Q  1.2661 m  0.0595
where m is the ratio of the percent depth doses at
20 cm and 10 cm depth, respectively. The percent
depth doses must be measured at SSD  100 cm
with a field size of 10 cm x 10 cm at the phantom
surface.
For beam quality specification measurements with acylindrical chamber, the chamber axis must be
shifted downstream by 0.5 r , where r is the inner
radius of the measuring volume. It is allowed to use
a plane-parallel chamber to determine beam
quality.

60

60

The beam quality index Q is to be measured foreach nominal accelerating voltage. Q is defined as
the ratio M 20 / M10 of two ionization readings of adosemeter at different depths. M 20 is obtained at
20 cm depth of water, M10 at 10 cm depth of waterat a fixed source-detector-distance SDD = 100 cm
and a field size of 10 cm x 10 cm at the depth ofmeasurement.

86

86

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High Energy Photon Beams

Beam Quality Index Q
Chamber Type0.50

PTW 23331/30015

1.0090 1.0053 1.0008 0.9987 0.9957 0.9907 0.9867 0.9841 0.9806 0.9771 0.9727 0.9652 0.9576 0.9487 0.9363

0.53

0.56

0.59

0.62

0.65

0.68

0.70

0.72

0.74

0.76

0.78

0.80

0.82

0.84

Rigid Stem
PTW 23332/30016

1.0071 1.0044 1.0015 0.9988 0.9962 0.9926 0.9880 0.9856 0.9812 0.9770 0.9727 0.9644 0.9570 0.9495 0.9376

Rigid Stem
PTW 23333

1.0078 1.0048 1.0016 0.9988 0.9960 0.9922 0.9875 0.9850 0.9816 0.9772 0.9719 0.9645 0.9581 0.9494 0.9363

PTW 30001/30010

1.0078 1.0048 1.0016 0.9988 0.9960 0.9922 0.9875 0.9850 0.9816 0.9772 0.9719 0.9645 0.9571 0.9494 0.9363

PTW 30002/30011

1.0099 1.0058 1.0016 0.9988 0.9960 0.9922 0.9895 0.9870 0.9836 0.9802 0.9759 0.9685 0.9620 0.9533 0.9412

PTW 30004/30012

1.0099 1.0068 1.0026 0.9998 0.9980 0.9942 0.9915 0.9890 0.9856 0.9822 0.9779 0.9715 0.9640 0.9563 0.9432

PTW 30006/30013

1.0058 1.0038 1.0006 0.9988 0.9960 0.9922 0.9875 0.9850 0.9806 0.9762 0.9709 0.9635 0.9551 0.9464 0.9333

PTW 31002/31010

1.0065 1.0036 1.0006 0.9988 0.9961 0.9924 0.9877 0.9853 0.9809 0.9766 0.9713 0.9640 0.9556 0.9469 0.9339

Semiflex
PTW 31003/31013

1.0065 1.0036 1.0006 0.9988 0.9961 0.9924 0.9877 0.9853 0.9809 0.9766 0.9713 0.9640 0.9556 0.9469 0.9339

Semiflex
PTW 31014

1.0052 1.0036 1.0012 0.9989 0.9977 0.9944 0.9912 0.9880 0.9839 0.9788 0.9737 0.9656 0.9574 0.9502 0.9388

PinPoint
PTW 31016

1.0052 1.0036 1.0012 0.9989 0.9977 0.9944 0.9912 0.9880 0.9839 0.9788 0.9737 0.9656 0.9574 0.9502 0.9388

PinPoint 3D
60

Table 6: k Q values for PTW cylindrical chambers [DIN 6800-2]. For Co beams k Q equals 1.000. The data forthe 31016 PinPoint 3D as well as the chambers 30015 and 30016 have been added by PTW-Freiburg.

Chamber TypeRadius r [mm]Correction Factor kr

PTW 0.6 cm³ Farmer
PTW 0.125 cm³ Semiflex
PTW 0.3 cm³ Semiflex
PTW 23331/30015 1.0 cm³ Rigid Stem
PTW 23332/30016 0.3 cm³ Rigid Stem
PTW 31014 0.015 cm³ PinPoint
PTW 31016 0.016 cm³ PinPoint 3D

3.05
2.75
2.75
3.95
2.50
1.00
1.45

1.009
1.008
1.008
1.012
1.008
1.003
1.004

Table 7: Radius of the measuring volume of PTW cylindrical chambers and values for the correction factor kr .
For details see Appendix A.

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Electron Beams

5 High Energy Electron Beams
5.1 IAEA TRS 398
60

5.1.1 Chambers calibrated at Co(5-1)

Dw  k Q  N w  M
Dw=absorbed dose to water

kQ

=

Nw

=

energy dependent correction factor, see
Table 8calibration factor for absorbed dose to60
water for Co

M=

corrected reading of the dosemeter, seechapter 2.1

Influence Quantity

Reference Condition

Phantom material

water(for beams with
R50  4 g / cm 2 (approx.
E 0  10 MeV ) a plastic
phantom may be used)

Chamberplane-parallel(for beams with
R50  4 g / cm 2 (approx.
E 0  10 MeV ) a cylindricalchamber may be used)Depthzref  0.6  R50  0.1 g / cm 2 (zref and R50 in g / cm 2 )Chamber positioning

effective point of measurement, see chapter 2.3

SSD

100 cmField size

10 cm x 10 cm at phantom
surface, or that used fornormalization of output factors, whichever is larger

The beam quality is specified by R50 , the depth inwater at which the absorbed dose is 50 % of its
value at the absorbed dose maximum4. R50 is to bemeasured under the above reference conditions,but at field sizes of at least
4

10 cm x 10 cm

for R50  7 g / cm2

20 cm x 20 cm

for R50  7 g / cm 2

From the depth ionization distribution measured
with an air-filled ionization chamber, the quantity
R50,ion is obtained. This quantity can be converted
to R50 by
R50  1.029  R50,ion  0.06 g / cm2(5-2)( R50,ion  10 g / cm 2 )R50  1.059  R50,ion  0.37 g / cm2

(5-3)

2

( R50,ion  10 g / cm )For beam quality specification measurements with acylindrical chamber, the chamber axis must be
shifted downstream by 0.5 r , where r is the inner
radius of the measuring volume. For R50  4 g / cm 2a plane-parallel chamber must be used.

5.1.2 Cross-calibration

IAEA TRS 398 recommends the cross-calibration ofplane-parallel chambers against a cylindrical cham60
ber which is calibrated at Co. Dose measurements
are performed under reference conditions (seechapter 5.1.1) using the highest available electronenergy Qcross .
Step 1: measure a reference dose Dw,Qcross with a60cylindrical chamber which was calibrated at Co,
following the procedure described in chapter 5.1.1.
Step 2: irradiate the plane-parallel chamber withthe same dose. Take the plane-parallel chamber's
corrected reading M and determine its calibration
factor for the energy used for cross-calibration

N w,Qcross 

Dw,QcrossM(5-4)

The mean energy E0 can be estimated by

E 0  2.33  R50 ( R50 in g / cm 2 and E0 in MeV).

88

88

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High Energy Electron Beams

Step 3: use the cross-calibrated plane-parallel
chamber to measure dose at any electron energy
Q other than Qcross

Dw 

kQ

kQcross

 N w,Qcross  M(5-5)

kQcross is the plane-parallel chamber's k Q value forthe cross-calibration energy Qcross . Values for k Q
are obtained from Table 8.

Electron
Beam
Quality
R50
2

PTW
23343

PTW
34045

PTW
34001

MarkusAdvanced
Markus

Roos

0.966
0.956
0.945
0.938
0.932
0.926
0.921
0.917
0.912
0.909
0.905
0.899
0.893
0.883
0.871
0.861
0.849

0.965
0.955
0.944
0.937
0.931
0.925
0.920
0.916
0.912
0.908
0.904
0.898
0.892
0.882
0.870
0.860
0.848

[g/cm ]

1.0
1.4
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
7.0
8.0
10.0
13.0
16.0
20.0



0.925
0.920
0.916
0.913
0.910
0.907
0.904
0.901
0.899
0.894
0.889
0.881
0.870
0.860
0.849

PTW
30001/
30010
Farmer

PTW
30002/
30011
Farmer

PTW
30004/
30012
Farmer

PTW
30006/
30013
Farmer

PTW
PTW
31002/
31003/
31010
31013
0.125 cm3 0.3 cm3
Semiflex Semiflex







0.911
0.909
0.907
0.905
0.904
0.901
0.898
0.893
0.885
0.877
0.868







0.916
0.914
0.912
0.910
0.909
0.906
0.903
0.897
0.890
0.882
0.873







0.920
0.918
0.916
0.915
0.913
0.910
0.907
0.902
0.894
0.887
0.877







0.911
0.909
0.907
0.905
0.904
0.901
0.898
0.893
0.885
0.877
0.868







0.912
0.910
0.908
0.906
0.905
0.901
0.898
0.893
0.885
0.877
0.867







0.912
0.910
0.908
0.906
0.905
0.901
0.898
0.893
0.885
0.877
0.867

Table 8: Typical k Q values for PTW plane-parallel and cylindrical chambers [IAEA 398] 5. The values for the
Advanced Markus chamber and the Farmer chambers type 30006/30013 have been added by PTWFreiburg. They were calculated according to IAEA TRS 3986.

5
6With corrigendum STI/DOC/010/398
For details refer to PTW's Technical Note D661.200.00

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Electron Beams

5.2 AAPM TG-51
60

5.2.1 Chambers calibrated at Co

Dw  PgrQ  k R 50  k ecal  N w  M
Dw

PgrQ

(5-6)

= absorbed dose to water= correction for gradient effects, not needed
for plane-parallel chambers. For cylindricalchambers with a cavity radius r the correction factor at the reference depth d ref isobtained fromPgrQ  M (d ref  0.5  r ) / M (d ref )10 cm x 10 cm

for R50  8.5 cm

20 cm x 20 cm

for R50  8.5 cm

From the depth ionization distribution measured
with an air-filled ionization chamber, the quantity I50
is obtained. This quantity can be converted to R50by
R50  1.029  I 50  0.06 cm( 2  I 50  10 cm ) (5-7)

R50  1.059  I 50  0.37 cm(I 50  10 cm )k R' 50= electron quality conversion factor, see
formulae (5-9) and (5-10)
k ecal = photon-electron conversion factor, see
Table 9N w = calibration factor for absorbed dose to60
water for Co= corrected reading of the dosemeter, seeMchapter 2.1

Influence Quantity

Reference Condition

Phantom material

water

Chamberplane-parallel preferred forR50  4.3 cm (10 MeV)
plane-parallel mandatory forR50  2.6 cm (6 MeV)

Depth

d ref  0.6  R50  0.1 cm

Chamber positioning

chamber axis for cylindricalchambers, effective point of
measurement for planeparallel chambers, seechapter 2.3

SSD

90 - 110 cm

Field size

≥ 10 cm x 10 cm at phantom
surface forR50  8.5 cm (20 MeV),≥ 20 cm x 20 cm at phantom
surface for R50  8.5 cm

The beam quality is specified by R50 , the depth inwater at which the absorbed dose is 50 % of its
value at the absorbed dose maximum. R50 is to bemeasured under the above reference conditions,but at SSD  100 cm and at field sizes at the phantom surface of at least
90

90

(5-8)

Chamber Typek ecal

PTW 34001 Roos
PTW 34045 Advanced Markus
PTW 23343 Markus
PTW 30001/30010 Farmer
PTW 30002/30011 Farmer
PTW 30004/30012 Farmer
PTW 30006/30013 Farmer
PTW 31003/31013 0.3 cm³ Semiflex
PTW 31002/31010 0.125 cm³ Semiflex
PTW 23331 1.0 cm³ Rigid Stem
PTW 23332/30016 0.3 cm³ Rigid Stem

0.901
0.905
0.905
0.897
0.900
0.905
0.896
0.898
0.898
0.896
0.898

Table 9: Values of the photon-electron conversion
factor k ecal . The values not listed inAAPM 51 have been added by PTWFreiburg; they were calculated according
to Rogers 1998.

For beam quality specification measurements with acylindrical chamber, the chamber axis must be
shifted downstream by 0.5 r , where r is the inner
radius of the measuring volume. Cylindrical chambers should be used only for R50  4.3 cm .
The electron quality conversion factor is obtained
from the following formulae with R50 expressed incm.
For cylindrical chambers and 2  R50  9 cm
R50

k R 50  0.9905  0.071 e 3.67

(5-9)

and

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Electron Beams

for well-guarded
2  R50  20 cm

plane-parallelk

R50  1.2239  0.145  (R50 )chambers

and

5.3 DIN 6800-2
60

0.214

(5-10)

5.3.1 Chambers calibrated at Co(5-13)

Dw  k r  k E  N w  M
Dw

5.2.2 Cross-calibration

AAPM TG-51 recommends the cross-calibration ofplane-parallel chambers against a cylindrical cham60
ber which is calibrated at Co. Dose measurements
are performed under reference conditions (seechapter 5.2.1) using the highest available
electron energy Qcross .
Step 1: measure a reference dose Dw,Qcross with a60cylindrical chamber which was calibrated at Co,
following the procedure described in chapter 5.2.1.
Step 2: irradiate the plane-parallel chamber withthe same dose. Take the plane-parallel chamber's
corrected reading M and determine its calibration
factor for the energy used for cross-calibration

N w,Qcross 

Dw,QcrossM(5-11)

Step 3: use the cross-calibrated plane-parallel
chamber to measure dose at any electron energy
Q other than QcrossDw 

k R' 50

k R'

50,Qcross

 N w,Qcross  M

kr

kE
Nw
M

= absorbed dose to water at zref
= 1 0.03 r replacement correction factor( r is the inner radius of the measuring
volume of a cylindrical chamber, given incm). kr is not applicable for plane-parallel
chambers)= k E  k E energy dependent correction factor,
see chapter 5.3.3= calibration factor for absorbed dose to60
water for Co= corrected reading of the dosemeter at zref ,see chapter 2.1

Influence Quantity

Reference Condition

Phantom material

water

Chamberplane-parallelfor R50  4 cm a cylindricalchamber can be usedDepthzref (see chapter 5.3.2)

Chamber positioning

effective point of measurement, see chapter 2.3

SSD

100 cmField size

20 cm x 20 cm at phantom
surface(5-12)

5.3.2 Determination of R 50 and zref

k R' 50 ,Qcross is the plane-parallel chamber's k R' 50 value
for the cross-calibration energy Qcross .

k R' 50 values are obtained from formula (5-10).

R50 is defined as the depth at which the absorbed
dose has dropped to 50 % of the maximum value.
R50 is determined from the corresponding value
R50,ion of a depth ionization curve, measured at
SSD  100 cm with a field size of 20 cm x 20 cm(optionally 10 cm x 10 cm for R50  7 cm )R50  1.029  R50,ion  0.06 cm (R50,ion  10 cm) (5-14)
R50  1.059  R50,ion  0.37 cm (R50,ion  10 cm) (5-15)

The reference depth for dose measurements isdefined as ( zref and R50 in cm)
zref  0.6  R50  0.1

D560.210.01/10(5-16)
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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Electron Beams

5.3.3 Determination of k E  k E'  k E"

5.3.4 Dose measurements at depths other thanzref

k E' is independent of the chamber type ( R50 in cm)

The dose at depth z is determined byk E'  1.106  0.1312  (R 50 )0.214

Dw ( z )  k r  kE  kNR  N w  M ( z )a)(5-17)

k E" for plane-parallel chambers is determinedfromk E" 

( p wall  pcav )R50( p wall  pcav )(5-18)(5-21)

kE is the correction factor at zref as described inchapter 5.3.3, kNR is given by

kNR 

Co

s w ,a ( z )pcav ( z )s w,a ( zref ) pcav ( zref )(5-22)

andThe relevant factors are listed in Table 10.
Chamber( pcav )types w ,a ( z ) ( pwall )R 50

R50( pwall  pcav )Coa  bx  cx ²  dy
1  ex  fx ²  gx ³  hy

(5-23)

where x  ln(R50 ) and y  z / R50 ( z and R50 incm) and

PTW 34001
Roos
PTW 34045
Adv. Markus
PTW 23343
Markus

1.000

0.981

1.000

0.985

1  0.037  e 0.27 R 50

0.982

Table 10: Perturbation correction factors for planeparallel chambers at the reference depth
zref [Christ 2002, Kapsch 2007, DIN
6800-2].

b) k E" for cylindrical chambers at the reference
depth zref is calculated fromk E" 

( pcav  pcel )R50( p wall  pcel )a=1.0752b = - 0.50867

c = 0.08867

d = - 0.08402

e = - 0.42806

f = 0.06463

g=

h = - 0.1246

0.003085

The cavity perturbation factor depends on thechamber typea)

Roos and Advanced Markus chambers
pcav ( z )  pcav ( zref )  1.000b)Markus chambers
pcav ( z ) (5-19)1 zbc R50  dz a  
R50


1 e

(5-24)

Co

with z and R50 in cm and with

and(pcav ) R 50  1  0.0217  r  e0.153R 50(5-20)

with r in mm and R50 in cm. r can be taken from
Table 7, ( p wall ) Co and ( pcel )R50 /( pcel )Co are listed inTable 11.

a = 0.1498
d = 4.0487
c)b = -21.7336

c = -4.3379

Cylindrical chambers

p cav (z)  1  0.02155  r  ez0.2852R 50 1 
 1.271R 50  0.23 (5-25)
with r in mm, z and R50 in cm.
92

92

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Absorbed Dose Determination in Photon and High Energy Electron Beams
High Energy Electron Beams

Chamber type(p wall ) Co

( pcel ) R50( pcel ) Co

PTW 23331 1 cm³ Rigid Stem

1.001

1.005

PTW 30015 1 cm³ Rigid Stem

1.000

1.005

PTW 23332 0.3 cm³ Rigid Stem

1.001

1.005

PTW 30016 0.3 cm³ Rigid Stem

0.999

1.005

PTW 23333 Farmer (3 mm build-up cap)

1.001

1.005

PTW 23333 Farmer (4.6 mm build-up cap)

1.001

1.005

PTW 30001/30010 Farmer

1.001

1.005

PTW 30002/30011 Farmer

0.991

1.000

PTW 30004/30012 Farmer

0.991

1.005

PTW 30006/30013 Farmer

1.001

1.005

PTW 31002/31010 0.125 cm³ Semiflex

1.001

1.005

PTW 31003/31013 0.3 cm³ Semiflex

1.001

1.005

PTW 31014/31015 PinPoint

0.998

1.005

PTW 31016 PinPoint 3D

0.998

1.005

Table 11: Perturbation and central electrode correction factors for cylindrical chambers [DIN 6800-2].
Chambers not listed in DIN 6800-2 have been added by PTW-Freiburg.

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Absorbed Dose Determination in Photon and High Energy Electron Beams
Measurements in Acrylic Phantoms

6 Measurements in Acrylic Phantoms
6.1 Generalsource-detector-distance [AAPM 21]

For dosimetry in high energy photon or electron
beams all dosimetry protocols described in thisdocument (IAEA TRS 398, AAPM TG-51, DIN
6800-2) require absorbed dose measurements inreal water. Solid state phantoms may only be used
for routine QA measurements, and a transfer factor
has to be established [AAPM 51]. The phantom
should extend at least 5 cm beyond all sides of the
field and at least 5 cm beyond the maximum depthof measurement [IAEA 398].

zw  1.136  z p

This chapter helps to establish transfer factors and'equivalent' measuring depths for measurements inacrylic (PMMA, Perspex, C5H8C2) phantoms.

60

for Co - 35 MV(6-1)

6.2.2 Excess scatter correction
In PMMA phantoms the fraction of scattered photons is increased compared with water phantoms.
To convert measuring values from PMMA to water,
the measuring value has to be multiplied by a correction factor kESC (Excess Scatter Correction).
Table 12 shows kESC values as a function of accelerator voltage and field size [AAPM 21].

6.3 High energy electrons
Solid phantoms may be used below 10 MeV to determine absorbed dose at z ref [IAEA 398]. The
measuring depth in water z w can be determinedfrom the measuring depth in PMMA z p assuming

6.2 High energy photons
6.2.1 Conversion of measuring depth
Photon beams are attenuated and scattered differently in water and solid phantoms. To take thesedifferences into account, correction procedures
have to be carried out.
Differences in photon beam attenuation are determined by the ratio of the mean linear attenuation
coefficients of water and PMMA. The measuring
depth in water z w can be determined from themeasuring depth in PMMA z p assuming the samethe same source-detector-distance(6-2)

z w  ρ  cpl  zp  1.120  zp

cpl is the depth scaling factor and ρ the nominal

density of PMMA [IAEA 398]. The reading in the
PMMA phantom M p must be corrected by the fluence scaling factor hpl to obtain the equivalentreading in water M(6-3)

M  hpl  M p  1.009  M p

Field size at depth (cm²)
Energy

Depth

(MV)

(cm)

5x5

10x10

20x20

30x30

Co

0.5
5.0

0.997
0.986

0.996
0.987

0.995
0.989

0.996
0.991

2

0.4
5.0

0.998
0.984

0.994
0.982

0.997
0.989

4

1.0
5.0

0.998
0.994

0.997
0.993

0.998
0.993

6

1.5
5.0

0.999
0.994

0.998
0.994

0.998
0.996

60

Table 12: kESC as a function of energy and field size.
94

94

D560.210.01/10

Absorbed Dose Determination in Photon and High Energy Electron Beams
References

7 References[AAPM 21]

A protocol for the determination of absorbed dose from high-energy
photon and electron beams. AAPM Task Group 21. Med. Phys. 10(6),Nov/Dec 1983, 741ff.

[AAPM 51]

AAPM's TG-51 protocol for clinical reference dosimetry of high-energy
photon and electron beams. Med. Phys. 26 (9), September 1999,
1847-1870[AAPM 51/2]

Addendum to the AAPM’s TG-51 protocol for clinical reference
dosimetry of high-energy photon beams. Med. Phys. 41 (4), April 2014,
041501ff.

[Christ 2002]

Christ, Dohm, Bruggmoser, Schüle: The use of plane-parallel chambers in electron dosimetry without any cross-calibration. Phys. Med.
Biol. 47 (2002), N121-N126[Christ 2004]

Christ, Dohm, Schüle, Gaupp, Martin: Air density correction inionization dosimetry. Phys. Med. Biol. 49 (2004), 2029-2039[Bruggmoser 2007]

Bruggmoser, Saum, Schmachtenberg, Schmid, Schüle: Determinationof the recombination correction factor kS for some specificplane-parallel and cylindrical ionization chambers in pulsed photon andelectron beams. Phys. Med. Biol. 52 (2007), N35-N50[Bruggmoser 2008]

G. Bruggmoser, private communication[DIN 6800-2]

DIN 6800: Dosismessverfahren nach der Sondenmethode für Photonen- und Elektronenstrahlung; Part 2: Dosimetrie hochenergetischer
Photonen- und Elektronenstrahlung mit Ionisationskammern, March
2008[DIN 6809-4]

DIN 6809: Klinische Dosimetrie; Part 4: Anwendung von Röntgenstrahlen mit Röhrenspannungen von 10 bis 100 kV in der Strahlentherapie und der Weichteildiagnostik, December 1988

[DIN 6809-5]

DIN 6809: Klinische Dosimetrie; Part 5: Anwendung von Röntgenstrahlen mit Röhrenspannungen von 100 bis 400 kV in der Strahlentherapie, February 1996

[IAEA 381]

The Use of Plane Parallel Ionization Chambers in High Energy
Electron and Photon Beams. Technical Reports Series No 381.
International Atomic Energy Agency Vienna, 1997

[IAEA 398]

Absorbed Dose Determination in External Beam Radiotherapy: An
International Code of Practice for Dosimetry Based on Standards ofAbsorbed Dose to Water. Technical Reports Series No. 398.
International Atomic Energy Agency Vienna, 2000
Corrigendum STI/DOC/010/398[IAEA 398/2]

Electronic Version of [IAEA 398], dated 05 June 2006 (V.12)

D560.210.01/10

95

95

Absorbed Dose Determination in Photon and High Energy Electron Beams
References[Kapsch 2007]

Kapsch, Bruggmoser, Christ, Dohm, Hartmann, Schüle: Experimental
Determination of pCo perturbation factors for plane parallel chambers.
Phys. Med. Biol. 52 (2007), 7167-7181[Rogers 1998]

Rogers, A new approach to electron-beam reference dosimetry. Med.
Phys. 25 (3), March 1998, 310-320

96

96

D560.210.01/10

Absorbed Dose Determination in Photon and High Energy Electron Beams
Appendix A: Summary of PTW Chamber Data

Appendix A: Summary of PTW Chamber Data
PTW Cylindrical Chambers
Type

Chamber

Measuring

No.

Name

Volume
[cm³]

30001

Farmer0.6

Wall0.275 mm PMMAElectrodeAl 1 mm

+ 0.15 mm C
30010

Farmer0.6

30011

Farmer, all

0.6

30002

graphite

30012

Farmer

0.335 mm PMMA

Farmer,30006

waterproof

31002

Semiflex

Al 1.1 mm

30015

30016

C 1 mm0.6

0.425 mm C

Al 1.1 mm

Semiflex

0.6

0.335 mm PMMA

Al 1.1 mm+ 0.09 mm C

57

3.05

0.14 ms

3.05

0.14 ms(400 V)(400 V)

79

3.05

0.125
0.125

Semiflex
Semiflex

0.3
0.3

Rigid Stem
Rigid Stem

1.0
1.0

Rigid Stem
Rigid Stem

0.3
0.3

PinPoint

0.015

PinPoint

0.03

PinPoint

0.016

57

0.55 mm PMMA

Al 1 mm78

+ 0.15 mm C

Graphite coated(1)

0.55 mm PMMA

Al 1.1 mm

78

Al 1.5 mm

78+ 0.15 mm C

Graphite coated(1)

0.55 mm PMMA

Al 0.9 mm

78

Al 1.5 mm

60+ 0.15 mm C

Graphite coated(1)

0.4 mm PMMA

Al 1.1 mm

73

Al 2 mm54

+ 0.15 mm C

Graphite coated(1)

0.35 mm PMMA

Al 0.85 mm

0.57 mm PMMA +0.57 mm PMMA +0.09 mm C

2.75

67

2.75

85

2.75

85

2.75

85
(2)

0.08 ms(400 V)

3.95

0.21 ms(400 V)

3.95

0.23 ms(400 V)

2.5

0.04 ms(400 V)

2.5

0.08 ms(400 V)

1.0

0.02 ms(400 V)

1.45

0.04 ms(400 V)(2)
Al 0.3 mm

0.08 ms(400 V)(2)
Al 0.3 mm

0.10 ms(400 V)(2)
Al 0.3 mm

0.10 ms(400 V)(2)

0.35 mm PMMA

0.14 ms(400 V)(1)

0.40 mm PMMA

0.57 mm PMMA +

3.05

(1)

0.55 mm PMMA

0.14 ms(400 V)(2)

0.09 mm C
31016(400 V)(2)

0.09 mm C
31015

0.14 ms

45

79+ 0.135 mm C
31014

nominal HV

[mm]
3.05

(2)

+ 0.135 mm C
23332

Volume0.425 mm C

+ 0.15 mm C
23331

tion Time at+ 0.09 mm C

+ 0.15 mm C

31013

Ion Collec-

Measuring

(2)

30013

31003

Radius of

Density[mg/cm²]

(1)

30004

31010

Wall Area

1.45

0.06 ms(400 V)(1) Graphite density 0.82 g/cm³(2) Graphite density 1.85 g/cm³

D560.210.01/10

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97

Absorbed Dose Determination in Photon and High Energy Electron Beams
Appendix A: Summary of PTW Chamber Data

PTW Plane Parallel Chambers
Type

Chamber

Measuring

Entrance

Electrode

No.

Name

Volume[cm³]

Window

0.39

1 mm PMMA

34001

Roos

Window

Electrode

Ion Collec-

Diameter

Area

Distancetion Time at[mm]

Density[mg/cm²][mm]

nominal HV

15.6

132

2

0.13 ms+ 0.02 mm C

(200 V)+ 0.1 mm Varnish
34045

Advanced

0.02

Markus0.87 mm PMMA +

5

106

1

0.4 mm Air

0.02 ms(300 V)+ 0.03 mm CH2(Polyethylene)
(3)
23343

Markus0.057

0.87 mm PMMA +

5.3

106

2

0.09 ms(300 V)

0.4 mm Air+ 0.03 mm CH2(Polyethylene)
(3)
23342

Soft X-Ray

0.02

0.03 mm CH2

3

2.8

1

(Polyethylene)
23344

Soft X-Ray

0.2

0.03 mm CH2(300 V)
13

2.8

1.5

(Polyethylene)
34013

Soft X-Ray

0.00530.03 mm CH2(Polyethylene)

0.02 ms

0.04 ms(400 V)

1.7

2.8

0.75

0.01 ms(400 V)(3) with protection cap in place98

98

D560.210.01/10

Index

Product Index
Product

Page

Product

Page

Advanced Markus chamber
Böhm extrapolation chamber
Bragg peak chamber
Check device
CT chamber
CURIEMENTOR chamber
Cylinder stem chamber
DIAMENTOR chamber
Diamond detector
Dosimetry diode
Extrapolation chamber
Farmer chamber
HDR chamber
Hp(10) secondary standard chamber
In-vivo detectors
LA48
LDR chamber
MAM detector
Markus chambermicroDiamond
Monitor chamber
NOMEX

18
56
21, 2236
38, 39
43
52
43
26
27-30
56
10-13
34
53
35
35
34
42
18, 1926
54, 5543

OCTAVIUS detector
PinPoint chamber
PS-10 spherical chamber
PS-50 spherical chamber
R/F/D detector
Radiation monitoring chamberRadioactive check device
Rigid stem chamber
Roos chamber
Semiflex chamber
SFD diagnostic chamber
Silicon detector
Soft X-ray chamber
SOURCECHECK 4π
Spherical chamber
STARCHECK
TK-30 spherical chamber
Transmission chamber
Well-type chamber
XLS chamber
X-ray leakage system

35
23-25
50
50
42
46-49
36
16, 1720
14, 1540, 41
27-30
31-33
34
48-51
35
51
54, 5534, 4343
43

Item Number Index
The item numbers below are without the leading letters. For complete ordering numbers, indicating the connecting system, see the according product page.

Item #
23236
23237
23238
23342
23343
23343/11
23344
23361
23392
23392/U5
30009
30010
30011
30012
30013
30015

Page
32
52
31
31
19
18, 19
32
52
57
57
38
10
11
12
13
17

Item #

Page

30016
30017
31010
31013
31014
31015
31016
32002
32003
32005
32007S
32008S
33002.1.009
33004.1.xxx
33005
33005.1.xxx

16
39
14
15
23
24
25
48
49
51
50
50
34
34
34
34

Item #
34001
34013
34014
34031
34035
34045
34060
34069
34070
34073
48001
48002.1.004
48002.1.007
48002.1.008
48002.3.003
48002.3.004

Page
20
33
54
46
53
18
40
41
21
22
48, 4914, 1523, 2425
10-13
16, 17Item #

Page

48004
48010
48012
60004
60005
60016
60017
60018
60019
60020
7262
7262/U10786
7862
981937981938

20
36
36
42
42
27
28
29
26
30
47
46, 4754
55
53
53

Some former detector types are not included in this catalogue as they have been replaced by new types. The following table shows
discontinued detector types and their replacements.
Detector name
Farmer, PMMA/Al
Farmer, all graphite
Farmer graphite/Al
Farmer, waterproof
0.125 cm3 semiflex
0.3 cm3 semiflex

Discontinued type
30001
30002
30004
30006
31002
31003

New type
30010
30011
30012
30013
31010
31013

Detector name
0.3 cm3 rigid stem
1 cm3 rigid stem
PinPoint 0.015 cm3
PinPoint 0.03 cm3
Dosimetry Diode P
Dosimetry Diode E

Discontinued type
23332
23331
31006
31009
60008
60012

New type
30016
30015
31014
31015
60016
60017

99

H E A LT H P H Y S I C S

NUCLEAR MEDICINEDIAGNOSTIC RADIOLOGY

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