X-RAY and GAMMA RAY DETECTORHIGH RESOLUTION CdTeCADMIUM TELLURIDE

XR-100T-CdTe

DETECTOR TECHNOLOGY ADVANCEMENT - The XR-100T-CdTe provides “off the shelf” performancepreviously available only from expensive cryogenically cooled systems.

BeWindowDetector
Temperature
Monitor

FETCooler
MountingStud
APPLICATIONS:		
• Medical X-Ray & Gamma Ray Detection			• Mammography, Radiology & Conventional X-Ray• Uranium & Plutonium Detection			• Portable X-Ray & Gamma Ray Instruments			
• Research & Teaching			• Nuclear Plant Monitoring			• X-Ray Fluorescence			• Art & Archaeology

All the critical connections between
the detector and preamplifier have been madeinternally to the XR-100T-CdTe to ensure
quick, first time operation by the user. TheXR-100T-CdTe is provided complete with BNC
connectors and power cable.

• CdTe-Diode Detector• Thermoelectric (Peltier) Cooler• Cooled FET• Beryllium Window• Temperature Monitor• Hermetic Detector Package (TO-8)• Wide Detection Range

The XR-100T-CdTe is capable of detecting energies
from a few keV to several hundreds of keV.
57Co Spectrum
122 keV

14.4 keVCounts

Model XR-100T-CdTe is a high performance X-Ray
and Gamma Ray Detector, Preamplifier, and Cooler
system using a 3 x 3 x 1 mm3 (or 5 x 5 x 1 mm3)
Cadmium Telluride (CdTe) diode detector mounted
on a two-stage thermoelectric cooler. Also mounted
on the cooler are the input FET and feedback components to the charge sensitive preamplifier. Theinternal components are kept at approximately -30°C
and can be monitored by a temperature sensitive
integrated circuit. The hermetic TO‑8 package ofthe detector has a light tight, vacuum tight 4 mil (100µm) Beryllium window.

FEATURES:

850 eV FWHM
530 eV FWHM

Energy (keV)

AMPTEK INC. 14 DeAngelo Drive, Bedford, MA 01730-2204 U.S.A.
Tel: +1 (781) 275-2242 Fax: +1 (781) 275-3470 email: sales@amptek.com http://www.amptek.com

SPECIFICATIONSMODEL XR-100T-CdTe
X-RAY and GAMMA RAY DETECTOR
GENERAL

Pin 4+8 Volt preamp power

Pin 5

Cooler power return

Pin 6

Cooler power (0 to +4 Volt @0.350 A max.)
Ground and shield

Detector Type

Cadmium Telluride (CdTe) DiodeDetector Areas

3 x 3 mm (9 mm2)
5 x 5 mm (25 mm2)

CaseDetector Thickness

1 mm

Other detector sizes (5x5x1mm) available on special orders.

Energy Resolution@ 122 keV, 57Co

9 mm2: <1.2 keV FWHM, typical
25 mm2: <1.5 keV FWHM, typical

Other Be window thicknesses available on special orders.

Dark Counts<5 x 10-3 counts/sec @ 10 keV<E <1 MeV

Collimator kit for high flux applications.

Be Window

4 mil thick (100 µm)

Preamplifier

Charge Sensitive, with Current
Divider Feedback

Case Size

3.00 x 1.75 x 1.13 in
7.7 x 4.4 x 2.9 cm

Case Weight

4.4 ounces / 125 g

Total PowerLess than 1 Watt

Operation Conditions

0oC to +40oC

Storage and Shipping
Typical -20°C to +50°C, 10 to 90% humidity
non condensing
Long-term storage 10+ years in dry environment¨

TUVRheinland

TUV Certification
Certificate #: CU 72072412 01
Tested to: UL 61010-1: 2004 R7 .05
CAN/CSA-C22.2 61010-1: 2004

INPUTS
Preamp Power± 8 Volts @ 25 mA

Detector Power+ 500 Volts @ 1 µA

Cooler Power

Current = 350 mA maximum
Voltage = 4 V maximumOUTPUTS
Preamplifier
Sensitivity
Polarity
Temperature Monitor
Sensitivity

0.82 mV/keV
Negative signal out
1 kΩ max. load
PX5: direct reading in K throughsoftwareOPTIONS

Components for vacuum applications.
See also XR-100CR specifications using Si-PIN for detectionof low energy X-Rays with high resolution (149 eV FWHM @5.9 keV, 55Fe).
Available in X-123CdTe configuration (see Figure 1).

MODEL PX5 DIGITAL PULSE PROCESSOR,
MCA and POWER SUPPLYPower to the XR-100T-CdTe is provided by the PX5. The PX5 isDC powered by an AC adaptor and provides both a variable
Digital Pulse Shaping Amplifier (0.2 μs to 100 μs shapingtime), the MCA function, and all necessary power supplies
for the detector and preamplifier. The PX5 connects via USB,
RS232, ot Ethernet to a PC. Please see PX5 specifications at
http://www.amptek.com/px5-.html.

VACUUM OPERATIONThe XR-100T-CdTe can be operated in air or in vacuum down
to 10-8 Torr. There are two ways the XR-100T-CdTe can beoperated in vacuum:1) The entire XR-100T-CdTe detector and preamplifier box canbe placed inside the chamber. In order to avoid overheating and dissipate the 1 Watt of power needed to operate theXR-100T-CdTe, good heat conduction to the chamber walls
should be provided by using the four mounting holes. An optional Model 9DVF 9-Pin D vacuum feedthrough connector
on a Conflat is available to connect the XR-100T-CdTe to thePX5 outside the vacuum chamber.
2) The XR-100T-CdTe can be located outside the vacuum
chamber to detect X-Rays inside the chamber through astandard Conflat compression O-ring port. Optional Model
EXV9 (9 inch) vacuum detector extender is available for thisapplication.

CONNECTORS
Preamp Output

BNC coaxial connector

Power and Signal

6-Pin LEMO connector (Part#ERA.1S.306.CLL)

Interconnect Cable

6-Pin, LEMO (Part# FFA.1S.306.
CLAC57) to 6-Pin LEMO (5 ftlength)

6-PIN LEMO CONNECTOR ON THE XR-100T-CdTe
Pin 1

Temperature monitor diodePin 2+ H.V. detector bias, +500 V

Pin 3:-8 Volt preamp power

FIGURE 1. The CdTe detector in the X-123CdTe configuration

THEORY OF OPERATIONMEDICAL APPLICATIONS

X-Rays and Gamma Rays interact with CdTe atoms to create an
average of one electron/hole pair for every 4.43 eV of energy lostin the CdTe. Depending on the energy of the incoming radiation,
this energy loss is dominated by either the Photoelectric Effect orCompton Scattering. The probability or efficiency of the detector
to “stop” the incoming radiation and create electron/hole pairs
increases with the thickness of CdTe. See Figure 2.
In order to facilitate the electron/hole collection process inthe CdTe detector, a +500 Volt potential is applied. This voltage
is too high for operation at room temperature, as it will cause excessive leakage, and eventually a breakdown. Since the detector
in the XR-100T-CdTe is cooled, the leakage current is reduced
considerably, thus permitting the high bias voltage.
The thermoelectric cooler cools both the CdTe detector
and the input FET transistor to the charge sensitive preamplifier.
Cooling the FET reduces its leakage current and increases thetransconductance, which in turn reduce the electronic noise ofthe system.
In order to further reduce the electronic noise, the feedback
capacitor and part of the current feedback network to the preamplifier are also placed on the same substrate as the detector andFET. This minimizes parasitic capacitance at the input.
A temperature monitoring sensor is placed on the cooled
substrate to provide a direct reading of the temperature of the internal components, which will vary with room temperature. Oncethe internal temperature gets below minus 10°C the performanceof the XR-100T-CdTe will not change with a temperature variation of a few degrees. Hence, accurate temperature control is notnecessary when using the XR-100T-CdTe inside the laboratory.

MEDICAL X-RAY TUBE SPECTRA for
MAMMOGRAPHY and RADIOLOGY• Direct Measurement Spectra• End Point Energy (kVp)• See what the patient gets
• No Compton corrections• Self-Calibrating System• Escape peaks adjustment with XRF-FP software• Look straight at the X-Ray tube and record simultaneously
the spectrum and the peak potential (kVp)• For Quality Assurance in Radiographic andFluoroscopic Systems

Design Objective
This detector system was designed with the objective of simultaneously measuring the X-Ray tube peak potential (kVp), andto characterize the mammography X-Ray tube spectrum.

Significance of the Measurement* Both the tube spectrum and the peak potential (kVp) are
important parameters affecting the image quality in filmscreen and digital mammography.
* Automatic selection of proper target/filter combinationin modern mammography systems maybe affected byimproper kVp.
* In conventional devices, the user depends on central laboratory calibration and has no easy way to calibrate the instrument during use.

X-Ray Tube Monitor for Mammography Machines
Direct Molybdenum (Mo) Spectrum at 28 kVp
17.5 keVCounts19.6 keVLog

End Point
Energy(kVp)

Linear

FIGURE 2. 1 mm Thick CdTe Detection Efficiency

024681012141617Energy (keV)19212325 27

29

X-Ray Tube Monitor for Radiology Machines
Direct Tungsten (W) Spectrum at 100 kVp
59.3 keVCounts67.2 keV

FIGURE 3. XR-100T-CdTe Gamma ray detector; PX5 digitalpulse processor, power supply, shaping amplifier and MCA;
and EXVC Collimator

0End Point
Energy (kVp)618294153657688100Energy (keV)
Spectra courtesy of Andrew Karellas, Ph.D., University ofMassachusetts Medical School, Worcester, MA 01655

XR-100T-CdTe TYPICAL PERFORMANCE
All spectra below were taken with a 3 x 3 x 1 mm thick CdTe-diode detector with the use of RTD.
All the spectra are taken with the Amptek MCA8000A multichannel analyzer.
241Am Spectrum

Lead (Pb) Fluorescence from 57Co

59.54 keV

600 eV FWHMCountsCounts

Pb Lα
10.5 keV

13.95

Pb Lγ
14.8 keV

390 eV keV
FWHM

22.1 keV

Pb Lβ
12.6 keVPb Kα175 keV

Pb Kα272.8 keV

Escape Peaks

Pb Kβ184.9 keV

Energy (keV)

Energy (keV)

109Cd Spectrum

137Cs Spectrum

Pb Kβ287.3 keV

430 eV
FWHM

CountsCounts662 keV

5.9 keV FWHM

88 keV

Energy (keV)

Energy (keV)

60Co Spectrum

Uranium Oxide Spectrum (UO3)
1.17 MeV
1.33 MeV

4.17 keV FWHM @ 1.17

Counts (Log)Counts (Log)565 eV FWHM

Energy (MeV)

Energy (keV)

133Ba Spectrum

5.9 keV

356 keVCountsCounts55Fe Spectrum

U-235
185.72 keV

290 eV FWHM5.1 keV FWHM

6.49 keV
Energy (keV)

Energy (keV)

AMPTEK INC.

14 DeAngelo Drive, Bedford, MA 01730-2204 U.S.A.

Tel: +1 (781) 275-2242 Fax: +1 (781) 275-3470

email: sales@amptek.com http://www.amptek.com