In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced ...In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured.Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared.It was confirmed that the results between calculated data and measured data showed the good agreement with each other.Finally,it was concluded that we have to take care the activation of beam line and target.But,it is not necessary to treat accelerator tank,surrounding materials,and building concrete as radioactive materials in case of decommissioning.展开更多
The rare radioactive-isotope(RI)ring is an isochronous storage ring for deriving the masses of extremely short-lived rare RIs.Since the successful commissioning experiment in 2015,the time of flight mass measurement t...The rare radioactive-isotope(RI)ring is an isochronous storage ring for deriving the masses of extremely short-lived rare RIs.Since the successful commissioning experiment in 2015,the time of flight mass measurement technique has been established through test experiments using unstable nuclei with well-known masses.The experiments for unknown masses were started in 2018.While conducting experiments,we continue to develop equipment to further improve the efficiency and precision of mass measurements.The upgraded kicker system can generate a magnetic field with an extractable duration equivalent to the revolution time of the ring.This is essential for extracting extremely rare events as well as shortening the measurement time compared with that in the initial experiments.New steering magnets make it possible to eliminate an uncertain vertical beam deviation that occurs upstream.As a result,we confirm that the extraction yield is increased.A new resonant Schottky pick-up is able to detect single particles in timeframes on the order of milliseconds.It will be useful not only for beam diagnostics but also for lifetime measurement experiments of extremely short-lived rare RIs planned as a future application.展开更多
文摘In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured.Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared.It was confirmed that the results between calculated data and measured data showed the good agreement with each other.Finally,it was concluded that we have to take care the activation of beam line and target.But,it is not necessary to treat accelerator tank,surrounding materials,and building concrete as radioactive materials in case of decommissioning.
基金Supported by RIKEN Pioneering Project funding and JSPS KAKENHI(17H01123,18H03695,21H04461,23K25876.)。
文摘The rare radioactive-isotope(RI)ring is an isochronous storage ring for deriving the masses of extremely short-lived rare RIs.Since the successful commissioning experiment in 2015,the time of flight mass measurement technique has been established through test experiments using unstable nuclei with well-known masses.The experiments for unknown masses were started in 2018.While conducting experiments,we continue to develop equipment to further improve the efficiency and precision of mass measurements.The upgraded kicker system can generate a magnetic field with an extractable duration equivalent to the revolution time of the ring.This is essential for extracting extremely rare events as well as shortening the measurement time compared with that in the initial experiments.New steering magnets make it possible to eliminate an uncertain vertical beam deviation that occurs upstream.As a result,we confirm that the extraction yield is increased.A new resonant Schottky pick-up is able to detect single particles in timeframes on the order of milliseconds.It will be useful not only for beam diagnostics but also for lifetime measurement experiments of extremely short-lived rare RIs planned as a future application.
