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

[摘要] 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 CO2operation. 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 C2F6as 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.

[发布机构] Los Alamos National Laboratory, Los Alamos; NM; 87545, United States^1;National Security Technologies, 182 Eastgate Dr, Los Alamos; NM; 87544, United States^2;Atomic Weapons Establishment, Reading, Aldermaston; RGR 4PR, United Kingdom^3;Lawrence Livermore National Laboratory, 7000 East Ave, Livermore; CA; 94550, United States^4;MIT Plasma Science and Fusion Center, 167 Albany St #204, Cambridge; MA; 02139, United States^5;Laboratory for Laser Energetics, 250 E River Rd, Rochester; NY; 14623, United States^6

[关键词] Calibration data;Cherenkov Detectors;Cherenkov photons;Cherenkov threshold;Detector models;Gamma ray measurements;National ignition facility;Temporal separation