1. GAMMA-IMAGING SYSTEMS FOR ECOLOGICAL AND NUCLEAR ENVIRONMENT MEASUREMENTS O.P.Ivanov Моscow, Россия

2. Schemes of portable  imagers
CCD
Pin-hole m
=m/f
-sources
Scintillating PSD
Shielding
d=m(L+f)/L
h=dL/f
=m(2R+1)/f
=m/f
Image intensifier L f d m
Coded mask

3. Results of radioactivity mapping
First computer controlled gamma-ray imager and scan results of contaminated pipelines of research reactors

4. Portable gamma camera for project Rehabilitation
Bright source on ground
Appearance of the gamma imager

5. Calibration & Measurements
K=Ntot/StD [(counts/s)/(Sv/hr)],
Nt total counts in source
S number of pixels in source
t accumulation time
D dose rate
Measurements of the instrument sensitivity, Cs-137 point source
The image of point source
Distance to the source, cm
Ntot, counts
S, pixels
t, s
D, Gy/hr
K, (counts/s)/(Gy/hr) 30
714825
1059
400
2.20
0.77
348695
1044
200
0.76 60
212280
915
0.80
0.72
128384
1088
0.74
Kav = 0.75(counts/s)/(Gy/hr)

6. Waste storage #4 broze Schematic of the radwaste repository.
1 – excavator used for radwaste extraction from the repository,
2 – additional shielding structure of concrete blocks with the ceiling of concrete plates,
3 – radwaste prepared for loading into containers,
4 – field of view of the gamma imager,
5 – ground level,
6 – gamma imager mounted on the stand at the repository entrance,
7 – radio-controlled BROKK robot,
8 – reinforced container for high-level radwaste.
broze
Superimposing of raw gamma-images presented in pseudo colours on black and white video images
Gamma images of the repository obtained during extraction of the high-level radwaste fragment

7. Monitoring of radwaste
Robot manipulation with high level radwaste controlled by continues gamma-ray imaging.
source
Monitoring the recovery of radwaste from the deep repository (on the left - the system is installed above the repository, right - the image of a bright source at the bottom of the repository)

8. Activities at MR research at reactor
Tests of radwaste packing into container
2,75 m
4,0 m
EDR : mGy/h

9. Rooms and equipment at nuclear facilities
EDR: 2 mGy/h
EDR : nGy/h
Views of a hot spot located on a plug under a heat exchanger in a very dose rate background (top) and a hot spot located just above the camera (bottom), with (left) the pinhole and (right) the coded-mask configurations.

10. Continues pseudo source
RayMoS camera
Continues pseudo source
EDR:1.1 mGy/h
 The intensity distribution of gamma radiation from a
Scattered radiation (nearly back scattering ~175 degrees) – virtual continues pseudo source of ~180 keV energy
Collimated Cs-137 point source scattered on a rectangular aluminum screen 30 mm.
=>

11. System for soil/groung scanning with scintillating PSD
HURA mask 9-th rank, W h= 1cm, scintillator CsI(Tl) D10x h1 cm, FoV 40о
At 15 m and backgroung 0.45∙106Bq/m2 (12µCi/m2) 1m above)
Registration of spot ~ 1x1 m with double activity in 30min

12. 2p circular imaging detector
Parameters: 35 pixels CsI(Tl) 50х10х5mm +tungsten 3mm, URA mask with 71 element, 200mm ImIn Proxitronic BV2584 Din25mm Sensitivity: Cs nGy Co nGy <3,7107Bq (1mCi) Cs-137 in 3min>
Signal
time
position

13. Results of application
Typical performances of developed systems are the following:
Gamma-channel FoV:
Angular resolution:
Sensitivity - registration of Cs-137 source for exposure dose:
0.05μGy (equivalent 3*108Bq (10mCi) at 10 m in 10 min) with pinhole
5nGy (equivalent 3*107Bq (1mCi) at 10 m in 10 min) with coded aperture