Journal Article

Gamma Ray Measurements at OMEGA with the Newest Gas Cherenkov Detector \GCD-3\

Young, C S, Gales, S, Leatherland, A, Kim, Y, Rubery, M, Zylstra, A B, Lopez, F E, Sedillo, T J, Stoeffl, W, Fatherley, V E, Johnson, M Gatu, Oertel, J A, Horsfield, C J, Herrmann, H W, Archuleta, T N, Batha, S H, Shmayda, W T, Malone, R M, McEvoy, A M, Aragonez, R J

2016

Overview

Initial results from the newest Gas Cherenkov Detector (GCD-3) are reported demonstrating improved performance over previous GCD iterations. Increased shielding and lengthening of the Cherenkov photon optical path have resulted in a diminished precursor signal with increased temporal separation between the precursor and the primary DT Cherenkov signal. Design changes resulted in a measured GCD-3 sensitivity comparable to GCD-1 at identical 100 psia CO2 operation. All metal gasket seals and pressure vessel certification to 400 psia operation allow for a GCD-3 lower Cherenkov threshold of 1.8 MeV using the fluorinated gas C2F6 as compared to the 6.3 MeV lower limit of GCD-1 and GCD-2. Calibration data will be used to benchmark GEANT4 and ACCEPT detector models. The GCD-3 acts as a prototype for the Super GCD being fielded at the National Ignition Facility (NIF) as part of the National Diagnostics Plan and will be installed at NIF in early 2016.

• Publisher: IOP Publishing
• Subject: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY / Cerenkov counters / Gamma rays / INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY / Physics / Precursors / Pressure vessels / Sensors / Shielding