1. JSC “Institute in Physical-Technical problems”
X-ray and gamma ray spectrometers based on cadmium telluride detectors
JSC “Institute in Physical-Technical Problems” is a branch company, specializing in the design and manufacture of spectrometers, detection units, and separate nuclear-physics instruments based on semiconductor and scintillation materials!
JSC “Institute in Physical-Technical problems”
141980, Dubna, Moscow region, Kurchatova str.4
Tel.: ; fax

2. For the diagnostics of physical processes in the nuclear-energetic installations of JSC IPTP a detection unit BDTK-1K with the cadmium telluride detector with the area of 47mm2 and thickness 1.1mm and with thermoelectric cooling of the head module has been developed.
The measuring results of the prototype of BDTK-1K are given below.
A digital signal processor (ЦСУ-B-1K) developed at JSC IPTP was used for the detection unit testing.

3. Advantages of the cadmium telluride detectors
High atomic number (Z=50) and high density which implies high efficiency in gamma radiation detection;
Sufficiently large band gap width – 1.5 eV (that of silicon is 0.9 eV and of germanium is 0.67 eV) permitting to operate at room temperature with a low level of current noises;
Energy resolution is much better than that of scintillation detectors which allows one to use them for applications where a resolution of separate adjacent lines is required;

4. Specifications of the BDTK-1K detection unit
Detected energy range –
from 5.9 to keV
Energy resolution :
by energy 5.9 keV – 0.62 keV;
by energy 59.6 keV – 0.93 keV;
by energy keV – 1.5 keV;
by energy keV – 6.4 keV.
Optimum operating voltage
of SCD until minus 400 V.
Optimum current of the cooler – 0.7 A.
Detection unit mass – 0.87 kg.
Overall size – 166×106×85 mm.

5. Relative efficiency of the detection depending on radiation energy
Energy, keV
counting reduced to output 100 %
Fitting at
Е > 100 keV
count in peak
output %
40.5 74
46.2
801830
14.8
122.08
543518
30.8
244.76
277519
285540
21480
7.74
344.14
106646
104137
29221
27.4
410.96
73673
61588
1665
2.26
443.66
53616
49099
1705
3.18
779.03
10469
9276
1340
12.8
964.43
7225
4931
1026
14.2
3750
3465
375 10
2338
3226
311
13.3
1058
1605
218
20.6
Starting from the energy Е>100 keV, the relative efficiency is well approximated by the following dependence:
εотн=
const / E-2.96

6. Resolution-energy dependence
Energy, keV
Resolution, keV
40.55
1.375
46.2
1.599
122.08
1.679
244.76
2.703
344.14
3.551
410.96
4.522
443.66
4.678
779.03
7.025
964.43
8.748
8.824
6.401
8.852

7. Fe-55 and Am-241 spectra Граница шумов – 1,9 keV 5.89 keV 13.94 keV

8. Co-57 and Cs-137 spectra Shaping time – 6 µs
32 keV
37 keV
122 keV
662 keV
Shaping time – 6 µs
Lines 32 and 37 keV are K-alpha and K–beta series of the Ba-137 isotope
generated at the Cs-137 decay.

9. Scintillation detectors
, нм
I, отн.ед.
Spectrum of radio-luminescence of the detectors
Density, g/cm … ….1,05
Maximum of the luminescence spectrum, nm…420

10. Scintillation detectors
Designaiton
Purpose
T, ns
ПС-Н1
Detection of fast neutrons
ПС-Б2
Detection of fast neutrons and photon radiation with high time resolution высоким временным разрешением
0.78
ПС-Б3
same
1.0
ПС-Б4
0.67
СПС-С10
Detection of photon radiation due to photoeffect on lead atoms (up to 10% by mass)
1.70
ПС-У14
Detection of photon radiation using the automatic sensitivity control circuit

11. Summary
Tellurid cadmium spectrometric systems are small in size and have a low power consumption.
CdTe detection units are promising for use in portable instruments and stationary complexes of the technologic parameters control at nuclear power plants and allow one to substantially increase the operation characteristics in applied studies, radiography, and astrophysics.
Detectors built with plastic scintillators have showed their advantage in radiation monitoring purposes.