Unfolding Directional Aerial Radiation Survey Maps for Improved Precision
Researchers present a novel method to unfold mobile radiation survey measurements, enhancing spatial precision and extrapolation validity. The approach provides insights on radioactivity distribution, crucial for on-site nuclear inspections under the CTBT. The use of direction-capable gamma detectors and imagers enables better assessment of restricted-access sites, offering a glimpse into the future of nuclear test monitoring.
Download Presentation
Please find below an Image/Link to download the presentation.
The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. Download presentation by click this link. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.
E N D
Presentation Transcript
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair* , A. McCann*, P.R.B. Saull , N.J. Murtha , A.M.L. MacLeod P2.2-619 * PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Mobile gamma radiation survey measurements are a key component of an on-site inspection conducted under the Comprehensive Nuclear-Test-Ban Treaty. ABSTRACT Previously, we have shown how direction-capable gamma detectors, or gamma imagers, can reconstruct radioactivity distributions in a restricted-access site from vantage points on its perimeter. In this work, we present a new method to unfold a set of mobile radiation survey measurements for the system response. By requiring the solution be consistent with the measurement from every sub-detector, at every position in the survey, simultaneously, this method greatly improves spatial precision and the distance over which extrapolation is valid. Most importantly, the method provides the significance of the observation of radioactivity in certain areas, and gives an upper limit on the amount of allowed radioactivity in other areas. Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) a State Party suspected of undertaking a nuclear test may be subject to Inspection by an international team. INTRODUCTION The inspected State Party may declare up to 50 km2 of restricted-access sites, each of area up to 4 km2. 2014 Integrated Field Exercise - Restricted Area Site N: Inspected country claimed that there had been an industrial accident in a 1000 m zone and it was not safe to go in. Viewing from the cliff at the perimeter of the restricted zone, 60 m away, was deemed to be safe. What if inspectors had had an imager or direction-capable detector on that cliff? P.R.B.Saull (NRC) et al., SCoTSS Gamma Imager for CTBTO On-site Inspection, talk from CTBT Science and Technology 2017 Conference, Vienna, Austria Development and Implementation of the 2014 Integrated Field Exercise Scenario, CTBT/PTS/TR/2015-1, June 2015 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 ARDUO direction-pointing gamma detector SCoTSS Compton gamma imager METHODS instruments UAV platform Ground-based vehicle ~1.6 kg of CsI(Tl) in 8 individual crystals ~15 kg of CsI(Tl) in 288 individual crystals Self-shielding configuration enables reconstruction of direction toward source. nanosecond-scale coincidence timing enables gamma imaging through reconstruction of Compton scattering events. Photo credits: Mike Franz, DRDC Suffield Research Centre, Canada Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Outdoor experimental trial data flying at 10 m altitude ARDUO self-shielding 185 MBq point Cs-137 sources RESULTS Arrows are projected into horizontal plane so appear shorter when near vertical Source location is well-reconstructed by mapping of count rate versus geographic location of UAV. The direction arrows calculated from self-shielding indicate the source location more precisely. 10 m altitude C.M. Chen, L.E. Sinclair, R. Fortin, M. Coyle, C. Samson, In-flight performance of the Advanced Radiation Detector for UAV Operations (ARDUO), NIM A 954 (2020) 161609. Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Vector back-projection of arrows into the plane of the horizon ARDUO self-shielding 185 MBq point Cs-137 sources RESULTS Perimeter of restricted access site Arrow length indicates significance If a restricted-access site were declared a no-fly zone, the direction-capable detector can still locate sources using measurements outside the perimeter by back- projection of the source direction arrows. Sinclair, L.E., Chen, C.M. Inspection of a Restricted Access Site Using UAV Perimeter Survey with the ARDUO Direction-Capable Gamma Spectrometer. Pure Appl. Geophys. (2020). https://doi.org/10.1007/s00024-020-02589-8 10 m altitude Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 New research question: How much can we learn on a single sortie? ARDUO self-shielding 185 MBq point Cs-137 sources RESULTS Arrows are projected into horizontal plane so appear shorter when near vertical The UAV system flies out from home base, uses up half a tank of gas , then returns. 10 m altitude Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Single sortie real-time count rate and directions map ARDUO self-shielding 185 MBq point Cs-137 sources RESULTS Arrows are projected into horizontal plane so appear shorter when near vertical counts per second Count-rate map for single sortie fails to indicate the presence of the more northern source. The direction arrows calculated from self-shielding are indicative of the second source but imprecise. 10 m altitude Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Single sortie vector back- projection ARDUO self-shielding RESULTS 185 MBq point Cs-137 sources Vector back-projection of the direction arrows into the plane of the horizon is suggestive of the actual source locations but highly imprecise. 10 m altitude Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 gMEAS data pixel 1 pixel 2 pixel 300 Represent the data by the one- dimensional array gMEAS. unfolding algorithm METHODS gMEAS has NMEAS bins, one for every crystal in the measurement array, or eight entries for every measurement location. iBin = iCrystal + 8 * iUAV We want the true distribution of radioactivity, f (x,y). Discretize the solution for the true distribution of radioactivity into NPIXELSf i (x,y) But what we have is gMEAS = S S [ f (x,y) ] where S S represents the effect of the measurement system on f (x,y). ? f (x,y) ?PIXELS?? Generate gi = S S [ fi(x,y) ] and fit gi to gMEAS to extract the wi. ?=1 Assume that f (x,y) can be adequately represented by Assure NPIXELS <NMEAS ?PIXELS?? f REC(x,y) = f i (x,y). ?=1 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Survey measurement unfolded for system response and extrapolation of measurement off of the survey line ARDUO self-shielding RESULTS Uncertainties define the confidence with which radioactivity is observed and the distance over which extrapolation from the measurement locations is reliable. 185 MBq point Cs-137 sources The measured data can not rule out the presence of significant radioactivity in the north-east quadrant kBq/m2 + kBq/m2 kBq/m2 Unfolded to ground level Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Extended source trial experimental setup and individual view-point gamma images SCoTSS imager RESULTS Gamma imager location and orientation Restricted access site Intended location of 35 GBq La-140 source N.J. Murtha, Reconstruction of a radioactive source distribution using a tomographic spatial unfolding method with Compton gamma imager measurements, Ph.D. Thesis, In Preparation, Carleton University, Ottawa, 2021 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Projection of gamma image from north- east view point SCoTSS imager RESULTS Gamma imager location Restricted access site Intended location of 35 GBq La-140 source N.J. Murtha, Reconstruction of a radioactive source distribution using a tomographic spatial unfolding method with Compton gamma imager measurements, Ph.D. Thesis, In Preparation, Carleton University, Ottawa, 2021 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Raw tomographic reconstruction of gamma images from all view-points SCoTSS imager RESULTS Gamma imager location Restricted access site Intended location of 35 GBq La-140 source N.J. Murtha, Reconstruction of a radioactive source distribution using a tomographic spatial unfolding method with Compton gamma imager measurements, Ph.D. Thesis, In Preparation, Carleton University, Ottawa, 2021 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 Tomogram unfolded for system response, with map of statistical uncertainties SCoTSS imager RESULTS The system response unfolding determines the quantitative amount of radioactivity and reveals the areas inside the restricted access site which are clear of radioactivity The radioactivity is reconstructed primarily in the expected locations N.J. Murtha, Reconstruction of a radioactive source distribution using a tomographic spatial unfolding method with Compton gamma imager measurements, Ph.D. Thesis, In Preparation, Carleton University, Ottawa, 2021 Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
Unfolding Directional Aerial Radiation Survey Maps to enable Extrapolation and Improved Precision L.E. Sinclair, A. McCann, P.R.B. Saull, N.J. Murtha, A.M.L. MacLeod, contact: laurel.sinclair@canada.ca Poster No.: P2.2-619 CONCLUSIONS Unfolding radiation survey measurements to remove the system response can improve spatial precision and enable extrapolation. Particularly important is that this process provides knowledge as to the significance of the measurement of radioactivity in different geographic locations. The unfolding process has been demonstrated for real data acquired in outdoor trials in geometries applicable to CTBT On-Site Inspection with Restricted-Access Sites for o o Aerial survey with ARDUO direction-capable gamma spectrometer mounted on UAV, and Ground-based mobile survey with SCoTSS gamma imager. This work has been partially funded by Defence Research and Development Canada s (DRDC s) Canadian Safety and Security Program. We grateful acknowledge collaboration by the scientists at DRDC s Suffield Research Centre. Disclaimer: The views expressed on this poster are those of the author and do not necessarily reflect the view of the CTBTO PUTTING AN END TO NUCLEAR EXPLOSIONS CTBTO.ORG
