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

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

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

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

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)

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

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)

Activities at MR research at reactor Tests of radwaste packing into container 2,75 m 4,0 m EDR : 25 mGy/h

Rooms and equipment at nuclear facilities EDR: 2 mGy/h EDR : 300 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.

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. =>

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) =>0.5µGy/h @ 1m above) Registration of spot ~ 1x1 m with double activity in 30min

2p circular imaging detector Parameters: 35 pixels CsI(Tl) 50х10х5mm +tungsten 3mm, URA mask with 71 element, 200mm ImIn Proxitronic BV2584 Din25mm Sensitivity: Cs-137 - 1.5 nGy Co-60 - 2.5 nGy <3,7107Bq (1mCi) Cs-137 source @10m in 3min> Signal time position

Results of application Typical performances of developed systems are the following: Gamma-channel FoV: 300 Angular resolution: 10 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