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Gamma ray camera

Requirement

Gamma Ray Camera for RH Waste Measurements and Detection and Surveying of low Activity Radiation

In high activity Remote Handled (RH) waste assay, nuclear decommissioning and low activity radiation detection and surveying there is a requirement for a gamma spectroscopy device with a wide range of both sensitivity and radiation tolerance. Such a device also has application in dose-rate surveying following an incident where radiation is released. Further to these requirements ANTECH was approached by the Argonne National Laboratory, where there was a specific need for RH measurements of activity in the Alpha Gamma Hot Cell Facility (AGHCF).

ANTECH Solution

RadSearch: Radioactivity and Decommissioning Monitor

In response to these requirements ANTECH has developed the RadSearch gamma camera with the following characteristics:

1. The instrument combines in one detector head a sensitive, shielded and highly collimated LaBr3 scintillation detector with an optical (video) camera with controllable zoom and focus and a laser range finder. The LaBr3 scintillation detector has an excellent energy resolution of typically 3% compared to NaI detectors (typically 7-8%).

2. The detector head is mounted on a pan/tilt mechanism with a range of motion of 360 degrees (pan) and +/- 90 degrees (tilt). The detector head with pan/tilt is normally mounted on a tripod but can also be mounted on vehicles or a mobile robot for access to high dose-rate areas.

3. RadSearch is controlled from a Remote Monitoring Station (RMS) consisting of a notebook computer and a small power supply unit. The RMS is connected to the detector head and pan and tilt mechanism by a single power and communications (Ethernet) cable of up to 80 metres in length.

4. Analysis software allows the gamma camera to measure the activity of scanned objects and surfaces and to locate radiation “hot spots”. It has an extensive library of radionuclides (over 40) that can be selected and identified. As RadSearch acquires an 8K-gamma spectrum for each Scan Element contributing to the Scan Area, scan data can be subsequently re-analyzed off-line for the presence of alternative radionuclides. The data is presented as a set of video images of the scanned area with a coloured overlay showing the distribution of radioactivity for each selected radionuclide.

Result

The ANTECH gamma camera RadSearch has been deployed at the AGHCF at the Argonne National Laboratory where it was used to survey areas of the hot cell facility. The activity of a number of different components was determined as well as the location of a piece of fuel that had fallen from a work station table and could not be located by visual inspection. Further testing of the device has established the minimum detectable activity (MDA) for 137Cs point source at one metre to be 0.91 uCi, corresponding to a dose-rate of 2.8 nSv/h.

Reference

Download RadSearch data sheet.

Download RadSearch technical note.

John A. Mason, Marc R. Looman, Adam J. Poundall, Daniel Pancake and Richard Creed, Development and Testing of a Novel Gamma ray Camera for Radiation Surveying, Contamination Measurement and Radiation Detection, Proceedings of INMM12, Orlando, Florida, July 2012. (12-A-409-INMM)

Daniel Pancake, “RadSearch Gamma Camera provides gamma camera characterization data for Argonne National Laboratory”Nuclear Decommissioning Report, Issue 1, Volume 3, January 2013.

J. A. Mason, R. Creed, M. R. Looman, D. Pancake, A. J. Poundall and A. C. N. Towner, “Testing and Performance Validation of a Sensitive Gamma Ray Camera Designed for Radiation Detection and Decommissioning Measurements in Nuclear Facilities- 13044”, WM2013 Conference, February 24 – 28, 2013, Phoenix, Arizona, USA. (WM13-13044)