title: Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.
abstract: When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation.
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: M J-E
authors.initials: MJ
authors.lastname: Manuel
authors.forename: M J
authors.initials: MJ
authors.lastname: Rosenberg
authors.forename: N
authors.initials: N
authors.lastname: Sinenian
authors.forename: H
authors.initials: H
authors.lastname: Rinderknecht
authors.forename: A B
authors.initials: AB
authors.lastname: Zylstra
authors.forename: F H
authors.initials: FH
authors.lastname: Séguin
authors.forename: J
authors.initials: J
authors.lastname: Frenje
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso