A new neutron time-of-flight detector for yield and ion-temperature measurements at the OMEGA Laser Facility

V Yu Glebov; C J Forrest; J Kendrick; J P Knauer; O M Mannion; H McClow; S P Regan; C Stoeckl; B Stanley; W Theobald

doi:10.1063/5.0101514

A new neutron time-of-flight detector for yield and ion-temperature measurements at the OMEGA Laser Facility

Rev Sci Instrum. 2022 Sep 1;93(9):093522. doi: 10.1063/5.0101514.

Authors

V Yu Glebov¹, C J Forrest¹, J Kendrick¹, J P Knauer¹, O M Mannion², H McClow¹, S P Regan¹, C Stoeckl¹, B Stanley¹, W Theobald¹

Affiliations

¹ Laboratory for Laser Energetics, University of Rochester, New York, New York 14623-1299, USA.
² Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.

PMID: 36182446
DOI: 10.1063/5.0101514

Abstract

A new neutron time-of-flight (nTOF) detector for deuterium-deuterium (DD)-fusion yield and ion-temperature measurements was designed, installed, and calibrated for the OMEGA Laser Facility. This detector provides an additional line of sight for DD neutron yield and ion-temperature measurements for yields exceeding 1 × 10¹⁰ with higher precision than existing detectors. The nTOF detector consists of a 90-mm-diam, 20-mm-thick BC-422 scintillator and a gated Photek photomultiplier tube (PMT240). The PMT collects scintillating light through the 20-mm side of the scintillator without the use of a light guide. There is no lead shielding from hard x rays in order to allow the x-ray instrument response function of the detector to be measured easily. Instead, hard x-ray signals generated in implosion experiments are gated out by the PMT. The design provides a place for glass neutral-density filters between the scintillator and the PMT to avoid PMT saturation at high yields. The nTOF detector is installed in the OMEGA Target Bay along the P8A sub-port line of sight at a distance of 5.3 m from the target chamber center. In addition to DD measurements, the same detector can be used to measure the neutron yield and ion temperature from deuterium-tritium (DT) implosion targets in the 5 × 10¹⁰ to 2 × 10¹² yield range. The design details and the calibration results of this nTOF detector for both D₂ and DT implosions on OMEGA will be presented.