Development of Neutron Streak Camera Using Recoil Protons

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06558064
• Research Category: Grant-in-Aid for Developmental Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: プラズマ理工学
• Research Institution: Osaka University
• Principal Investigator: MIYANAGA Noriaki Osaka University, Associate Professor Institute of Laser Engineering, レーザー核融合研究センター, 助教授 (80135756)
• Co-Investigator(Kenkyū-buntansha): IIDA Toshiyui Osaka University, Associate Professor Department of Engineering, 工学部, 助教授 (60115988) ; AZECHI Hiroshi Osaka University, Associate Professor Institute of Laser Engineering, レーザー核融合研究センター, 助教授 (90135666)
• Project Period (FY): 1994 – 1995
• Keywords: Neutron / Streak camera / Recoil proton / Inertial confinement fusion / Dense plasma

Research Abstract

For the application to the diagnostics of inertial confinement fusion plasma, we have developed a new type of streak camera which uses recoil protons in a plastic cathode. The distinctive characteristics and performances are as follows ;
1) We calculated the detection efficiency for 14.1-MeV (D-T) neutrons. This calculation is based on the Monte-Carlo code which treats the energy slowing-down of protons in the plastic cathode. The differential cross section of neutron scattering by hydrogen and the angular-dependent energy of recoil protons are also taken into account. The detection efficiency increases with increasing the cathode thickness, then saturates to an asymptotic value at the thickness exceeding the range (2.2mm) of forward scattered proton. The maximum detection efficiency was inferred to be 0.4%.
2) The time-of-flight spread of neutrons and recoil protons causes the degradation of time resolution. The time spread of the emission of secondary electrons saturates to be about 5ps at the cathode thickness of 2.2mm.
3) We have constructed a detection system which has a streak tube of 25-mm cathode diameter. This streak camera was examined using an ultraviolet short pulse laser. The measured time resolution is better than 12ps at a sweep speed of 26mm/ns on the output phosphor screen.
4) The time resolution of this neutron streak camera was estimated to be 14-19ps for the typical width (100-300mum) of cathode slit.
5) This neutron streak camera can be applicable to the laser fusion experiments if the total neutron yield is (3.5-7) *10^9.