Development of a pulsed neutron three-dimensional imaging system using a highly sensitive image-intensifier at J-PARC

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J‑PARC)

“…Once the target trolley is withdrawn into the maintenance room, the component replacement or repairing work is carried out using a power manipulator and some master-slave manipulators. Before removing the target, cover gas in the surge tank was transferred to an off-gas process system to reduce the radioactivity of gaseous radioactivity, especially 127 Xe and 3 H, accumulated in the cover gas. The transferred cover gas is stored in gas holders of the off-gas process system for about 12 months waiting for the decay of 127 Xe having half-life of 36.4 days, while 3 H is absorbed by a molecular sieve (synthetic zeolite) [23], and then released to the environment after checking the radioactivity.…”

“…Before removing the target, cover gas in the surge tank was transferred to an off-gas process system to reduce the radioactivity of gaseous radioactivity, especially 127 Xe and 3 H, accumulated in the cover gas. The transferred cover gas is stored in gas holders of the off-gas process system for about 12 months waiting for the decay of 127 Xe having half-life of 36.4 days, while 3 H is absorbed by a molecular sieve (synthetic zeolite) [23], and then released to the environment after checking the radioactivity. This gas transfer operation is repeated until the radioactivity of 127 Xe decreased down to 1/100 of its initial value, which is significantly below the allowable value even if the remaining 127 Xe in the loop is released through the stack of the building at any failure.…”

“…The key devices installed in instruments of MLF, such as MAGIC chopper [120], wavelength-shifting fiber scintillator detector [121][122][123], and SEOP system, were developed using NOBORU. The innovative pulsed-neutron imaging instrument, RADEN at BL-22, also uses R&D experiences of the imaging experiment conducted using NOBORU [124][125][126][127][128][129]. Recent development of white neutron holography enables us to observe the 3D local structure of boron-doped materials.…”

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments

“…The key devices installed in instruments of MLF, such as MAGIC chopper [120], wavelength-shifting fiber scintillator detector [121][122][123], and SEOP system, were developed using NOBORU. The innovative pulsed-neutron imaging instrument, RADEN at BL-22, also uses R&D experiences of the imaging experiment conducted using NOBORU [124][125][126][127][128][129]. Recent development of white neutron holography enables us to observe the 3D local structure of boron-doped materials.…”