Czech Metrology Institute  
Okružní 31, 638 00 Brno  
 
1. ------IND- 2018 0338 CZ - EN- ------ 20180803 --- --- PROJET 
Executive summary for the EC (not part of this legislation)  
Spectrometric assemblies for analysing alpha, beta, gamma  and neutron sources or fields —alpha 
and gamma radiation spectrometers are placed on the market and put into use in the Czech Republic 
pursuant to Act  No 505/1990 on metrology, as amended.  
The subject matter of this notified legislation is to lay down metrolog ical and technical 
requirements for these measuring instruments. The legislation also lays down the tests to be used 
for type approval and verification.  
(End of executive summary.)  
 
Contact person: Mgr. Tomáš 
Hendrych  
Phone: +420  545 555 414 
 
As the authority with substantive and territorial jurisdiction in the matter of laying down metrological 
and technical requirements for legally controlled measuring instruments and stipulating the testing 
methods used for type approval and verification of legally  controlled measuring instruments pursuant 
to § 14(1) of Act  No 505/1990, on metrology, as amended (hereinafter referred to as the ‘Metrology 
Act’), and in accordance with the provisions of §  172 et seq. of Act  No 500/2004, the Administrative 
Procedure Cod e (hereinafter referred to as the ‘APC’), the Czech Metrology Institute (hereinafter 
referred to as the ‘CMI’) commenced ex officio proceedings pursuant to §  46 APC on 4  April  2016, 
and, on the basis of supporting documents, issues the following:  
 
 
I. 
DRAF T  G E N E R A L  M E A S U R E  
number: 0111 -OOP -C077 -16 
 
laying down the metrological and technical requirements for legally controlled 
measuring instruments, including testing methods for type approval and verification 
of the following legally controlled measuring instruments:  
‘spectrometric assemblies for analysing alpha, beta, gamma  and neutron sources or 
fields —alpha and gamma radiation spectrometers’  
 General Measure No 0111 -OOP -C077 -16 
2 1 Basic definitions  
For the purposes of this general measure, terms and definitions pursuant to VIM and VIML,1) as well 
as the terms and definitions stated below shall apply:  
1.1 
activity  
the quotient of the expectation value of spontaneous nuclear transitions of an amount of a radionuclide 
in a particular energy state over a short time interval and this time interv al 
The unit of activity is the becquerel (Bq), where 1  Bq = 1  s-1. 
1.2 
FWHM  
full width at half maximum, characterises the instrument’s resolution  
1.3 
peak -to-Compton ratio  
the ratio of the maximum impulse count at the full absorption peak and the average height of the 
corresponding Compton continuum  
This ratio is usually given for the 1  333 keV (60Co) energy line. The corresponding Compton 
continuum is defined by the 1  040 keV to 1  096 keV interval.  
1.4 
nuclear radiation spectrometer  
an instrument designed  to measure radiation intensity distribution relative to its energy  
1.5 
variation coefficient V 
the coefficient of standard deviation 𝑠 and arithmetic mean 𝑥̅ of a set of 𝑛 measurements 𝑥𝑖given by 
the equation:  
𝑉=𝑠
𝑥̅=1
𝑥̅∙√1
𝑛−1∙∑(𝑥𝑖−𝑥̅)2𝑛
𝑖=1 
2 Metrological requirements  
2.1 Reference conditions and standard test conditions  
The reference and ambient test conditions based on the relevant requirements of European standards 
are given in Table  1. Different conditions may be specified by the manufactu rer. 
Table 1 – Reference conditions and standard test conditions  
Influence quantity  Reference conditions  Normal test conditions  
Ambient temperature  20 °C 18 °C to 22  °C 
                                                      
1) International Vocabulary of Metrology —Basic and General Concepts and Associated Terms (VIM) and 
International Vocabulary of Terms in Legal Metrology (VIML) are part of the technical harmonisation 
compendium ‘Terminology in the field of metrology’, which is  publicly accessible at www.unmz.cz . (1) General Measure No 0111 -OOP -C077 -16 
3 Relative humidity  65 % 50 % to 75  % 
Atmospheric pressure  101.3  kPa 86 kPa to 106  kPa 
Supply voltage  nominal supply voltage UN UN ± 1 % 
AC supply voltage frequency  nominal frequency  nominal frequency ± 0.5  % 
AC supply voltage waveform  sinusoidal  sinusoidal with total harmonic 
distortion of less than 5  % 
Background gamma radiation  air kerma rate 0.20  μGy·h-1 air kerma rate of less than 
0.25 μGy·h-1 
Electrostatic field  negligible  negligible  
Exterior electromagnetic field  negligible  less than the lowest value causing 
disturbances  
Exterior magnetic field  negligible  less than twice the Earth’s 
magnetic field  
Controls  set for normal operation  set for normal operation  
Radionuclide contamination  negligible  negligible  
Contamination by chemical 
products  negligible  negligible  
2.2 Measuring range  
The measuring range of the spectrometer (in terms of energy and rates) shall be specified by the 
manufacturer. The manufacturer shall also specify any peak position extension and shift for the 
maximum input rate of impulses.  
2.3 System linearity  
The deviations  of measured and reference values within the range of the measured rates shall not 
exceed 10  %. 
2.4 Instrument accuracy  
The measured activity value of the reference source shall not differ by more than 10  % from the 
conventionally true value plus the uncer tainty of the radioactive source (at the 95  % probability level).  
2.5 Energy resolution  
The measured FWHM value shall be better than or equal to the manufacturer’s specifications.  
2.6 Peak -to-Compton ratio  
The measured peak -to-Compton ratio shall be better  than or equal to the manufacturer’s specifications.  
2.7 Statistical fluctuations  
In light of the statistical nature of the interaction of ionising radiation with matter, the measured values 
may fluctuate around the mean value. When measurements of the sam e reference source are repeated 
using identical measurement geometry, the variation coefficient shall not exceed 5  %. 
2.8 Stability  
After the measuring instrument has been in operation for at least one hour, the measurement results 
shall not change by more  than 10  % of the measured value during the next 100  hours.  General Measure No 0111 -OOP -C077 -16 
4 3 Technical requirements  
3.1 Design  
A nuclear radiation spectrometer usually consists of a detector, an amplifier, an analogue -to-digital 
converter, an evaluation unit and various input and output  units.  
The design of spectrometers shall take into account the operating conditions of their expected 
applications.  
3.2 Electromagnetic compatibility  
3.2.1 Resistance to electromagnetic disturbances  
The operation of the measuring instrument shall not be affected by electromagnetic disturbances in the 
surrounding environment. It shall function normally after electromagnetic compatibility tests have 
been conducted.  
3.2.2 Radiation of electromagnetic fields  
During operation, the measuring instrument shall no t emit electromagnetic fields that could adversely 
affect the operation of other systems.  
3.3 Safety  
The measuring instrument must be safe in the sense defined within the basic safety principles for 
ionising radiation equipment and the requirements of the relevant technical regulations under normal 
conditions of use for the intended purposes.  
3.4 Software  
Software that is critical for the metrological characteristics of the measuring instrument (legally 
relevant software) shall be identifiable in accordance  with the WELMEC  7.2 guide, as amended2. The 
program me must be easily identifiable.  
4 Labelling the measuring instrument  
4.1 Markings on the measuring instrument  
The following shall appear on the measuring instrument:  
a) identification of the manufacturer;  
b) identification of the type of measuring instrument;  
c) serial number of the measuring instrument and its evaluation units;  
d) type-approval mark.  
All marks and inscriptions shall be easily visible under normal conditions, legible, durable, clear and 
irremovable.  
4.2 Placement of the official mark  
The placement of the official marks shall be specified in the type -approval certificate.  
                                                      
2 WELMEC  7.2, 2015: Software Guide (Measuring Instruments Directive  2014/32/EU) —available on -line at 
<www.welmec.org > General Measure No 0111 -OOP -C077 -16 
5 As far as practicable, the marks shall be placed on the front panel of the measuring instrument so that 
none of the provided inform ation is obscured.  
5 Type approval of the measuring instrument  
5.1 In general  
The process of type approval of the measuring instrument includes the following tests:  
a) external inspection;  
b) functional tests;  
c) tests of resistance to environmental disturbances;  
d) electromagnetic compatibility tests.  
5.2 External inspection  
The following shall be assessed during the external inspection:  
a) the completeness of the required technical documentation, including operating instructions;  
b) the conformity of the metrological and technical characteristics specified by the manufacturer 
in the documentation with the requirements of this regulation referred to in Chapters  2 and 3; 
c) the completeness and condition of the measuring instrument’s functional units according to the 
prescribed  technical documentation;  
d) conformity of the measuring instrument’s software (SW) version with the version specified by 
the manufacturer.  
5.3 Functional tests  
5.3.1 Linearity  
The linearity test shall be conducted using a set of standard reference sources on  the activity of one 
radionuclide (identical geometry), which covers the range of rates within which the measuring 
instrument is normally used.  
Any peak position shift and extension with increasing rates must not exceed the limits referred to in 
Article  2.2. The resulting measurement must fall within the limits referred to in Article  2.3. 
5.3.2 Accuracy  
The accuracy test shall be conducted across the entire energy range by measuring reference sources 
chosen with regard to the use of the equipment (radionuclide, geometry).  
The result of the measured activity shall be within the limits referred to in Article  2.4. 
5.3.3 Energy resolution  
During the test, the FWHM on the chosen energy line of the spectrum shall be established.  
662 keV (137Cs) shall be used for gamma radiation spectrometers with a scintillation detector and 
1 333 keV (60Co) for spectrometers with a germanium semiconductor detector. The reference value for 
soft photon radiation spectrometers with a Si(Li) detector shall be equal to 5.9  keV (55Fe). 
The energy resolution of alpha radiation spectrometers with silicon semiconductor detectors shall be 
tested for energy of 5.155  MeV (239Pu). 
The measured FWHM value shall comply with the requirement referred to in Article  2.5. General Measure No 0111 -OOP -C077 -16 
6 5.3.4 Peak -to-Compton ratio  
The test shall be conducted for germanium gamma radiation detectors (HPGe) for energy of 1  333 keV 
(60Co). 
The measured peak -to-Compton ratio shall comply with the requirement referred to in Article  2.6. 
5.3.5 Repeatability of measure ment —short -term stability  
During the test, the activity of a single reference source shall be repeatedly established. At least 10 
measurements shall be conducted in the same geometric configuration.  
The calculated variation coefficient shall comply with the requirement referred to in Article  2.7. 
5.3.6 Long -term stability  
During the long -term stability test, activity values of the reference source shall be recorded after 
1 hour, 10  hours and 100  hours from initiating the instrument without further adjustm ent. 
The measured activity values (corrected for half -life) shall comply with the requirement referred to in 
Article  2.8. 
5.4 Tests of resistance to environmental disturbances  
5.4.1 Resistance to climatic influences  
Measuring instruments designated to be u sed for field measurements shall be tested to the extent 
specified by the manufacturer.  
5.5 Electromagnetic compatibility tests  
Electromagnetic compatibility tests shall be conducted in accordance with the relevant standards to the 
extent so as to ensure t hat the requirements referred to in Articles  3.2.1 and 3.2.2 are complied with.  
The subsequent resistance tests shall primarily concern measuring instruments connected to the power 
grid; only the tests referred to in Articles  5.5.1, 5.5.2 and 5.5.8 shall b e relevant for battery -powered 
portable measuring instruments.  
5.5.1 Immunity to electrostatic discharges  
Immunity to electrostatic discharge shall be tested using a ±4  kV contact discharge and a ±8  kV air 
discharge.  
After the test has been conducted, the measuring instrument shall operate as designed. In the 
subsequent accuracy test, the measured value shall not exceed the limits referred to in Article  2.4. 
5.5.2 Immunity to radio frequency electromagnetic fields  
Immunity to the effects of radio frequency electromagnetic fields shall be tested in the following 
frequency ranges:  
 80 MHz to 1  GHz—field intensity 3  V·m-1; 
 1.4 MHz to 2  GHz—field intensity 3  V·m-1 and  
 2 MHz to 2.7  GHz—field intensity 1  V·m-1. 
The test field shall be amplitude -modulated to a depth  of 80  %; the modulation signal shall have a 
sinusoidal waveform with a frequency of 1  kHz.  
During the test, the measuring instrument shall operate as designed. In the subsequent accuracy test, 
the measured value shall not exceed the limits referred to in Article  2.4. General Measure No 0111 -OOP -C077 -16 
7 5.5.3 Immunity to short -term voltage dips  
During the test of immunity to short -term voltage dips, the supply voltage shall be reduced to 70  % of 
the nominal voltage for a period of 25 cycles of AC voltage, to 40  % of the nominal voltage for a 
period of 10 cycles and to 0  % of the nominal voltage for a period of one cycle.  
After the test has been conducted, the measuring instrument shall operate as designed. In the 
subsequent accuracy test, the measured value shall not exceed the limits referred  to in Article  2.4. 
5.5.4 Immunity to voltage interruptions  
Immunity to short -term voltage interruptions shall be tested by applying a voltage dip to 0  % of the 
nominal supply voltage for a period of 250 cycles of AC voltage.  
Temporary loss of function of the measuring instrument during the test is allowed provided that its 
operation is restored after the test is completed (either by itself or by operator’s intervention). In the 
subsequent accuracy test, the measured value shall not exceed the limits referr ed to in Article  2.4. 
5.5.5 Immunity to fast transitional events  
Immunity to fast transitional event shall be tested using a signal consisting of impulses (a leading edge 
of 5 ns, length —for the 50  % level —shall be 50  ns) combined into groups (duration of  15 ms). The 
repetition rate in the group shall be 5  kHz.  
The test signal voltage shall be chosen as follows:  
±2 kV on the AC or DC supply voltage terminals,  
±1 kV on the terminals for connecting I/O lines not directly connected to the mains,  
±2 kV on the terminals for connecting I/O lines directly connected to the mains.  
After the test has been conducted, the measuring instrument shall operate as designed. In the 
subsequent accuracy test, the measured value shall not exceed the limits referred to in Articl e 2.4. 
5.5.6 Immunity to electrical surges  
Immunity to electrical surges shall be tested using a surge of tr/th = 1.2/50  (8/20)  μs with a voltage of:  
±2 kV asymmetric and ±1  kV symmetric on AC or DC mains inputs,  
±1 kV asymmetric on inputs of I/O lines longer than 30  m not directly connected to the mains,  
±2 kV asymmetric and ±1  kV symmetric on inputs of I/O lines directly connected to the mains.  
After the test has been conducted, the measuring instrument shall operate as designed. In the 
subsequent accu racy test, the measured value shall not exceed the limits referred to in Article  2.4. 
5.5.7 Immunity to disturbances induced by high -frequency fields of power lines  
Immunity to disturbances from power lines shall be tested in the 150  kHz to 80  MHz frequenc y range. 
Voltage of 3  V shall be supplied to the terminals for connecting to AC or DC mains and to the 
terminals of I/O lines.  
During the test, the measuring instrument shall operate as designed. In the subsequent accuracy test, 
the measured value shall no t exceed the limits referred to in Article  2.4. 
5.5.8 Radiated electromagnetic disturbance  
During the test, emissions of high -frequency power line disturbances in the 150  kHz to 30  MHz 
frequency range and radiated disturbances in the 30  MHz to 1  GHz freque ncy range shall be 
measured. The relevant limits are given in Tables  2, 3 and 4. Stricter limit values shall apply to 
frequencies corresponding to frequency band boundaries.  General Measure No 0111 -OOP -C077 -16 
8 Table 2 – Limits for disturbances emitted on the mains i nput terminals  
Frequency range (MHz)  Disturbance limit values dB (μV)  
quasi -peak  average  
0.15 to 0.50  79 66 
0.50 to 30  73 60 
Table 3 – Limits for disturbances emitted on I/O lines  
Frequency range (MHz)  Disturbance limit values dB (μV)  
quasi -peak  average  
0.15 to 5  97 to 89  84 to 76  
5 to 30  89 76 
Table 4 – Limits for disturbances from radiation at a measuring distance of 10  m 
Frequency range (MHz)  Disturbance limit values dB 
(μV/m)  
quasi -peak  
30 to 230  40 
230 to 1  000 47 
6 Initial verification  
6.1 In general  
Initial verification shall include the following tests:  
a) visual inspection;  
b) accuracy test of the instrument.  
6.2 Visual inspection  
The purpose of the visual inspection shall be to asses s: 
a) compliance of the measuring instrument with the approved type;  
b) completeness of the measuring instrument according to the type -approval certificate;  
c) functionality and intactness of individual components of the measuring instrument;  
d) conformity of the SW version with the version approved in the context of type approval.  
6.3 Functional tests  
6.3.1 Linearity  
The test of linearity of the measuring instrument shall be conducted in accordance with Article  5.3.1.  
6.3.2 Accuracy  
The test of accuracy of the measuring instrument shall be conducted in accordance with Article  5.3.2.  General Measure No 0111 -OOP -C077 -16 
9 7 Subsequent verification  
Subsequent verification shall be conducted using a procedure identical to that for the initial 
verification in Chapter  6. 
8 Measuring instrument examination  
When examining measuring instruments pursuant to §  11a of the Metrology Act at the request of a 
person who may be affected by their incorrect measurement, the procedure in Chapter  7 shall be 
followed. The maximum permissible error shall be doub le the maximum permissible errors in 
Chapter  7. 
9 Notified standards  
For the purposes of specifying the metrological and technical requirements for measuring instruments 
and specifying the testing methods for their type approval and verification stemming f rom this general 
measure, the CMI shall notify the Czech technical standards, other technical standards or technical 
documents of international or foreign organisations, or other technical documents containing more 
detailed technical requirements (hereinaf ter referred to as ‘notified standards’). The CMI shall publish 
a list of these notified standards attached to the relevant measures, together with the general measure, 
in a manner accessible to the public (on www.cmi. cz). 
Compliance with notified standards or parts thereof shall be considered, to the extent and under the 
conditions laid down in the general measure, as compliance with those requirements laid down in this 
measure to which these standards or parts thereof  apply.  
Conformity with the notified standards is one way of demonstrating compliance with the requirements. 
These requirements may also be met by using another technical solution guaranteeing an equivalent or 
higher level of protection of legitimate inter ests. 
II. 
G R O U N D S  
The CMI has issued this general measure laying down metrological and technical requirements for 
legally controlled measuring instruments and tests for the type approval and verification of these 
legally controlled measuring instruments —‘spectrometric assemblies for analysing alpha, beta, 
gamma  and neutron sources or fields —alpha and gamma radiation spectrometers’ in accordance with 
§ 14(1)(j) of the Metrology Act to implement §  6(2), §  9(1) and (9) and §  11a(3) of the Metrolo gy Act.  
Implementing Decree  No 345/2002 specifying measuring instruments for mandatory verification and 
measuring instruments subject to type approval, as amended, classifies this type of measuring 
instruments under items  8.1, 8.6, 8.8 and 8.10 in the anne x entitled ‘List of the types of legally 
controlled measuring instruments’ as measuring instruments subject to type approval and mandatory 
verification.  
This legislation (General Measure) will be notified in accordance with Directive (EU)  2015/1535 of 
the European Parliament and of the Council of 9  September  2015 laying down a procedure for the 
provision of information in the field of technical regulations and of rules on Information Society 
services.  General Measure No 0111 -OOP -C077 -16 
10 III. 
I N S T R U C T I O N S  
In accordance with §  172(l) APC, in co njunction with §  39(l) APC, the CMI has stipulated a time limit 
for comments of 30  days as of the date of posting the draft on the official notice board. Comments 
submitted after this time limit will not be considered.  
The persons concerned are hereby invi ted to comment on this draft general measure. With regard to 
§ 172(4) APC, the comments shall be submitted in writing.  
With regard to §  174(l) APC, in conjunction with §  37(l) APC, it must be clearly stated who is making 
the comments, which general measure  the comments concern, how the draft contradicts legislation or 
how the general measure is inaccurate and must contain a signature of the person making the 
comments.  
The supporting documents for this draft general measure may be consulted at the Czech Metr ology 
Institute, Legal Metrology Department, Okružní 31, 638 00 Brno, after making arrangements by 
telephone.  
This general measure shall be posted for 15  days.  
 
 
 
 .…………………………..............  
RNDr. Pavel Klenovský  
Director -General  
 
 
Person responsible for accuracy: Mgr. Tomáš Hendrych  
 
Posted on:  
Signature of the authorised person confirming posting:  ................................ .......................   
 
Removed on:  
Signature of the authorised person confirming removal:  ................................ .....................