1. Extra-light gamma-ray imager for safeguards and homeland security
Oleg P Ivanov, and Ilya A. Semin, Victor N. Potapov, Vyacheslav E. Stepanov
Kurchatov Institute, Moscow

2. Contents Gamma-ray imaging principles Scheme of imager
Types of used coded masks
Scheme of remote measurements
Measurements and using of imager
Future developments

3. Gamma-ray imaging. Coded masks principles
Pin-hole
photoreadout m
=m/f
-sources
Schilding
Position sensitive detector
d=m(L+f)/L
h=dL/f
=m(2R+1)/f
=m/f
Image intensifier L f d m
Coded mask

4. Gamma-ray imaging. Coded masks principles
The scheme of gamma-imaging using coded aperture
[object ]
[ shadow-gram on detector]
[ image restored ]
[ aperture (mask )]
[ decoding software ]

5. The scheme of imager and used coded masks
FoV, video
FoV, gamma
, gamma 10
Figure 2. The selected configuration of a lightweight camera to search for the strong gamma-ray sources in emergency situations
Fig. 3. Photos of masks of two types - hex mask of 17 rank , and a square mask MURA 31 below.

6. Detector of imager and its weight characteristics
Produced system has the following weighting parameters (grams):
Tablet PC
960
Detector Medipix2 assembly
110
Cables 80
The detector enclosure and the mask
740
Overall system frame
720
Total
2610
Fig. 4 Detector Medipix2/Timepix with communication module FITPix before installing into the detector housing with block of coded mask.

7. Scheme of remote measurements with imager
Fig. 5 Scheme of remote measurements and photo the gamma camera which is autonomously set during measurements
RW Measurements & Certification

8. Using of imager for RW measurements
Dose rate ~ 400Sv/h
From source ~ 100Sv/h
T exp min
D exp Sv
Fig. 6. Gamma- image of canisters with radwaste made by portable camera. Main isotope Cs-137. Dose exposure 10Sv

9. Using of imager for RW measurements
Fig. 7 Gamma image of Cs-137 source obtained when operator holding the camera in his hands (Screenshot of control software)
Fig. 9 Gamma-ray imaging of packages with HLRW. Main gamma emitter is Co-60.
Fig. 8 Laboratory image of very weak Am-241 source – part of old fire alarm system

10. Imaging sensitivity Gamma spectra measurements with imager
FoV of video ~ 490.
FoV of gamma ~ 300 .
Sensitivity in dose units for masks of 2 mm thickness (source Cs-137, Еg = 662keV ) ~ 0.3 Sv (30 R)
(source Co-60, Еg = 1.25MeV ) ~ 3 Sv (300 R)
Fig. 10 Spectrum of Cs-137 source obtained via special processing of signal of gamma-ray detector Medipix2 of developed gamma-camera.

11. Future developments for imager
Fig. 11 A square mask of 11 rank 4 mm thickness to improve a sensitivity of imager.
To make more light system there is possibility to implement measurement modules with compact embedded single board computer which will be controlled via Wi-Fi from operator’s computer. The structure of such design is presented in the Fig. 12.
Fig. 12. Schematic representation of the structure of the system for gamma imaging with the use by a portable gamma camera.

12. Thank You for Attention
Thank You for Attention!!! Questions at any time: , 9547