title: Signal and background considerations for the MRSt on the National Ignition Facility (NIF).
abstract: A Magnetic Recoil Spectrometer (MRSt) has been conceptually designed for time-resolved measurements of the neutron spectrum at the National Ignition Facility. Using the MRSt, the goals are to measure the time-evolution of the spectrum with a time resolution of ∼20-ps and absolute accuracy better than 5%. To meet these goals, a detailed understanding and optimization of the signal and background characteristics are required. Through ion-optics, MCNP simulations, and detector-response calculations, it is demonstrated that the goals and a signal-to background >5-10 for the down-scattered neutron measurement are met if the background, consisting of ambient neutrons and gammas, at the MRSt is reduced 50-100 times.
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Wink
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Frenje
authors.affiliation: General Atomics, San Diego, California 92186, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Hilsabeck
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: R
authors.initials: R
authors.lastname: Bionta
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: H Y
authors.initials: HY
authors.lastname: Khater
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: M
authors.initials: M
authors.lastname: Gatu Johnson
authors.affiliation: General Atomics, San Diego, California 92186, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Kilkenny
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: F H
authors.initials: FH
authors.lastname: Séguin
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso