Development of gamma ray detector pixels for neutron-diagnosed subcritical experiments (LA-UR-20-25620)

Andrew L. Cooper; J. Winkelbauer; P. Koehler; G. Rusev; R. Olson; P. Pazuchanics; J. Tinsley; R. Buckles; I. Garza; J. A. Green; A. Guckes

doi:10.1117/12.2570832

20 August 2020 Development of gamma ray detector pixels for neutron-diagnosed subcritical experiments (LA-UR-20-25620)

Andrew L. Cooper, J. Winkelbauer, P. Koehler, G. Rusev, R. Olson, P. Pazuchanics, J. Tinsley, R. Buckles, I. Garza, J. A. Green, A. Guckes

Author Affiliations +

Proceedings Volume 11494, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXII; 114940R (2020) https://doi.org/10.1117/12.2570832
Event: SPIE Optical Engineering + Applications, 2020, Online Only

Abstract

During the dynamic compression of a subcritical object that is simultaneously receiving a neutron pulse, its fission 𝛾-ray signal can be measured and the die-off in its time-response is directly correlated with peak reactivity and neutron multiplication within. Hence, the signal measured by a time-of-flight (TOF) gamma detector array operating in currentmode is a convolution of the incident neutron pulse, detector time response, and fission signal from the object. Accurate determination of the true fission 𝛾-ray emission rate from the object requires a detector that is both highly sensitive (to preserve statistics) and fast (to minimize distortion of the signal shape from the object). In collaboration with scientists at Mission Support and Test Services (MSTS) and the Nevada National Security Site (NNSS), a TOF 𝛾-ray detection system was designed at Los Alamos National Laboratory (LANL) to meet these experimental objectives. This system consists of a 3-m-diameter array of ∼ 150 hexagonal detector pixels, each operating in current mode. Each pixel consists of a large-volume, fast-plastic scintillator coupled to a 5-in photomultiplier tube via a plastic light guide that uses total internal reflection for optical transport to the photocathode. Development details of this pixel design using statistical and time response metrics, laboratory measurements of full pixels and photomultiplier tubes, and high-fidelity GEANT4 simulations, are given. In closing, fielding considerations and expected performance capabilities for the full detector array are also described.

Conference Presentation

Citation Download Citation

Andrew L. Cooper, J. Winkelbauer, P. Koehler, G. Rusev, R. Olson, P. Pazuchanics, J. Tinsley, R. Buckles, I. Garza, J. A. Green, and A. Guckes "Development of gamma ray detector pixels for neutron-diagnosed subcritical experiments (LA-UR-20-25620)", Proc. SPIE 11494, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXII, 114940R (20 August 2020); https://doi.org/10.1117/12.2570832

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available