Speaker
Dr
Kentaro Toh
(J-PARC center, Japan Atomic Energy Agency)
Description
A median point calculating method was introduced to the wavelength-shifting-fibre based neutron image detector to increase the spatial resolution. The detector was originally developed for the neutron diffraction instrument, SENJU, at the Japan Proton Accelerator Research Complex J-PARC. The detector head was comprised of 64x2 of wavelength shifting fibres placed in x, and y directions each in a 4-mm pitch. The fibres were sandwiched with the ZnS/10B2O3 scintillator sheets at the up and downstream of the fibres. The neutron-induced scintillation light was collected in each WLS fibre in a photon counting mode to ensure high detector efficiency. The original method of position determination for a detected neutron was with a coincidence between fibres in x and y that counted more than a threshold number of photoelectrons. The conventional method intrinsically determined the pixel size of the detector to the fibre pitch. By implementing the median point calculating method the detector reproduced neutron images with a finer effective pixel size and position information than the fibre pitch. This result clearly demonstrated the effectiveness of this interpolation method even to the detector working based on a photon counting mode. This kind of position determination method is especially useful in diffraction measurements in which the finer position information than the fibre pitch is often required for data analysis. Moreover the implementation of the method does not require any change on detector hardware settings, simply changing the calculation program to the FPGA-based signal processing electronics. In the presentation the spatial responses of the detector measured with a collimated neutron beam are compared both with the conventional and median point calculating method.
Preferred medium (Oral/poster)
poster
Author
Dr
Takuro Kawasaki
(J-PARC center, Japan Atomic Energy Agency)
Co-authors
Mr
Atsushi Birumachi
(Nuclear Science Research Institute, Japan Atomic Energy Agency)
Dr
Kaoru Sakasai
(Japan Atomic Energy Agency)
Dr
Kazuhiko Soyama
(J-PARC center, Japan Atomic Energy Agency)
Dr
Kentaro Toh
(J-PARC center, Japan Atomic Energy Agency)
Prof.
Masaki Katagiri
(Frontier Research center for Applied Atomic Sciences, Ibaraki University)
Mr
Masumi Ebine
(Nuclear Science Research Institute, Japan Atomic Energy Agency)
Dr
Takaaki Hosoya
(Faculty of Engineering, Ibaraki University)
