title: The coincidence counting technique for orders of magnitude background reduction in data obtained with the magnetic recoil spectrometer at OMEGA and the NIF.
abstract: A magnetic recoil spectrometer (MRS) has been built and successfully used at OMEGA for measurements of down-scattered neutrons (DS-n), from which an areal density in both warm-capsule and cryogenic-DT implosions have been inferred. Another MRS is currently being commissioned on the National Ignition Facility (NIF) for diagnosing low-yield tritium-hydrogen-deuterium implosions and high-yield DT implosions. As CR-39 detectors are used in the MRS, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). The coincidence counting technique was developed to reduce these types of background tracks to the required level for the DS-n measurements at OMEGA and the NIF. Using this technique, it has been demonstrated that the number of background tracks is reduced by a couple of orders of magnitude, which exceeds the requirement for the DS-n measurements at both facilities.
authors.affiliation: Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Casey
authors.forename: J A
authors.initials: JA
authors.lastname: Frenje
authors.forename: F H
authors.initials: FH
authors.lastname: Séguin
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.forename: M J
authors.initials: MJ
authors.lastname: Rosenberg
authors.forename: H
authors.initials: H
authors.lastname: Rinderknecht
authors.forename: M J-E
authors.initials: MJ
authors.lastname: Manuel
authors.forename: M
authors.initials: M
authors.lastname: Gatu Johnson
authors.forename: J C
authors.initials: JC
authors.lastname: Schaeffer
authors.forename: R
authors.initials: R
authors.lastname: Frankel
authors.forename: N
authors.initials: N
authors.lastname: Sinenian
authors.forename: R A
authors.initials: RA
authors.lastname: Childs
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso
authors.forename: V Yu
authors.initials: VY
authors.lastname: Glebov
authors.forename: T C
authors.initials: TC
authors.lastname: Sangster
authors.forename: M
authors.initials: M
authors.lastname: Burke
authors.forename: S
authors.initials: S
authors.lastname: Roberts