title: Impact of x-ray dose on the response of CR-39 to 1-5.5 MeV alphas.
abstract: The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-Kα and Kβ x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula.
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J
authors.initials: J
authors.lastname: Rojas-Herrera
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: H G
authors.initials: HG
authors.lastname: Rinderknecht
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Zylstra
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: M
authors.initials: M
authors.lastname: Gatu Johnson
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: D
authors.initials: D
authors.lastname: Orozco
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rosenberg
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: H
authors.initials: H
authors.lastname: Sio
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: F H
authors.initials: FH
authors.lastname: Seguin
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Frenje
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: C K
authors.initials: CK
authors.lastname: Li
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso