Enhancing sensitivity of portal monitoring at varying transit speed

Schroettner, T; Kindl, Peter; Presle, Gerard

doi:10.1016/j.apradiso.2009.04.015

Cited by 10 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We did not consider the signal shape during the profile, because either the vehicle is assumed stationary, or the total neutron counts over the entire profile are used. References [4,5,9,10] provide analyses appropriate for alarm rules that do consider signal shape during the profile.…”

Section: Discussion and Summarymentioning

confidence: 99%

Pass/Fail Criterion for a Simple Radiation

Burr

Gavron²

2012

View full text Add to dashboard Cite

One of the simplest tests of a radiation portal monitor (RPM) is a series of n repeats (a vehicle drive-through) in which the i th repeat records a total number of counts X i and alarms if X i ≥ T where T is an alarm threshold. The RPM performance tests we consider use n repeats to estimate the probability p = P(X i ≥ T). This paper addresses criterion A for testing RPMs, where criterion A is: for specified source strength, we must be at least 95% confident that p ≥ 0.5. To assess criterion A, we consider a distribution-free test and a test relying on assuming the counts X i have approximately a Poisson distribution. Both test options require tolerance interval construction.

show abstract

Section: Discussion and Summarymentioning

confidence: 99%

Pass/Fail Criterion for a Simple Radiation

Burr

Gavron²

2012

View full text Add to dashboard Cite

show abstract

“…The height of the source off the ground would also need to be considered in relation to the detector height if one aimed to relate μ 1 to the source strength as defined by the mass of the neutron emitter. Instead, our study compares the DPs (i.e., statistical power) for the six statistical tests for specified maximum count rates μ 1 at x = 0, and uses Equation (1) to describe the source strength as a function of x for a given value of d. For completeness here we note that for gamma detectors, Schroettner, Kindl, and Presle (2009) evaluated the dependence of μ 1 on d, which, as mentioned, depends on detector size relative to the range of ds evaluated and on shielding effects. In the case of neutrons, shielding effects are larger for lower-atomic number shielding materials, particularly hydrogenous materials such as foam peanut-type packing material or water.…”

Section: Source Signalsmentioning

confidence: 99%

Moving Neutron Source Detection in Radiation Portal Monitoring

Burr

Hamada

2013

Technometrics

View full text Add to dashboard Cite

Radiation detection systems are deployed at U.S. borders to guard against entry of illicit radioactive material. This article uses realistic simulated data under different vehicle and illicit material scenarios to compare the performance of six detection methods for analyzing neutron count data collected as a vehicle passes through a radiation portal monitor, that is, a neutron count vehicle profile. The six methods are based on the cumulative count, the maximum count, sequential cumulative sum, sequential exponentially weighted moving average, comparison against a matched filter (MF) library, and a new estimated MF that estimates the shape of a neutron count vehicle profile.

show abstract

“…In the latter case a series of runs were performed with the threat in various discrete locations along the trajectory, the results from which were then integrated in time assuming a 2 s acquisition time. Previous works [18,19] have considered the impact of varying the vehicle velocity and integration time, but this is beyond the scope of the present work. In all runs 10 7 particles histories were calculated, which resulted in reaction rates with statistical errors of less than 3%.…”

Section: Ground Materialsmentioning

confidence: 99%

Optimising the neutron environment of Radiation Portal Monitors: A computational study

Gilbert¹,

Ghani²,

McMillan³

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

He detectors a b s t r a c t Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model 3 He detector system we have conducted a parameter study to identify the optimum combination of detector shielding, moderation, and collimation that maximises the sensitivity of neutron-sensitive RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Furthermore, optimisation of the air gap surrounding the helium tubes also improves detector efficiency.

show abstract

Enhancing sensitivity of portal monitoring at varying transit speed

Cited by 10 publications

References 15 publications

Pass/Fail Criterion for a Simple Radiation

Pass/Fail Criterion for a Simple Radiation

Moving Neutron Source Detection in Radiation Portal Monitoring

Optimising the neutron environment of Radiation Portal Monitors: A computational study

Contact Info

Product

Resources

About