title: Photonuclear reaction based high-energy x-ray spectrometer to cover from 2 MeV to 20 MeV.
abstract: A photonuclear-reaction-based hard x-ray spectrometer is developed to measure the number and energy spectrum of fast electrons generated by interactions between plasma and intense laser light. In this spectrometer, x-rays are converted to neutrons through photonuclear reactions, and the neutrons are counted with a bubble detector that is insensitive to x-rays. The spectrometer consists of a bundle of hard x-ray detectors that respond to different photon-energy ranges. Proof-of-principle experiment was performed on a linear accelerator facility. A quasi-monoenergetic electron bunch (Ne = 1.0 × 10(-6) C, Ee = 16 ± 0.32 MeV) was injected into a 5-mm-thick lead plate. Bremsstrahlung x-rays, which emanate from the lead plate, were measured with the spectrometer. The measured spectral shape and intensity agree fairly well with those computed with a Monte Carlo simulation code. The result shows that high-energy x-rays can be measured absolutely with a photon-counting accuracy of 50%-70% in the energy range from 2 MeV to 20 MeV with a spectral resolution (Δhν/hν) of about 15%. Quantum efficiency of this spectrometer was designed to be 10(-7), 10(-4), 10(-5), respectively, for 2-10, 11-15, and 15-25 MeV of photon energy ranges.
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sakata
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Arikawa
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ikenouchi
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Morace
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Utsugi
authors.affiliation: Institute of Scientific and Industrial Research, Osaka University, Ibaraki 565-0047, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kato
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakai
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shiraga
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fujioka
authors.affiliation: Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Azechi