Speaker
Masatoshi Arai
(European Spallation Source ERIC)
Description
Neutronics calculation is a key component to design radiation facility. There are well established and reliable codes for radiation transportation calculation, such as MCNPX, GEANT4, PHITS, etc. Shielding design to keep the dose rate lower than regulation is of the main importance.
However, at neutron scattering facility radiation will not be contained just within a shield of source, but a large fraction of neutrons needs to be lead out to instruments, with diminishing high energy neutrons and gammas as much as possible. Because of this situation a holistic view/analysis of radiation field is very important to make the facility safe and functional.
Accelerator system can be well separated from the target station and instrument. Proton beam is injected to the target, but radiation from accelerator itself cannot make any substantial effect to those other component. On the other hand radiation created at the target should be well shielded by the monolith biological shield, and at the same time a large fraction of radiation, neutrons and gammas, go out the monolith and are transported to instrument. Therefore, Holistic radiation analysis is indispensable for the success of the facility.
Neutron instruments sometimes have a long flight path, ~100m, and it is a quite difficult task to perform simulation through whole path. So, some innovative technique would be necessary. In this talk, I will show you how instrument beam line shield calculation and design was performed at J-PARC, and how we achieved very low background as well as radiation dose field with a very cost effective way.
Primary author
Masatoshi Arai
(European Spallation Source ERIC)
