Simulation Test

2017-07-28 (金) 17:35:23 (2255d)

Simulation testing for 132Sn and 56Ni

Performance study of the OEDO beam-line is in simulation, and a following figure schematically shows the scheme of deceleration in typical cases of neutron-rich 132Sn and neutron-deficient 56Ni.

Initial condition of 132Sn is calculated by assuming a production via projectile-fission reaction of 238U at 345A MeV, which is obtained by LISE++ code so as to maximize a yield of 132Sn. Thickness of the degrader at F1 is determined by considering a matching between an energy of beam and phase of RF deflector. After F3 focus, two stage degrading scheme is considered. The 132Sn (56Ni) beam of 50A MeV is produced by a mono-energetic degrader at FE8 and is transported to the RF deflector. The RF deflector kicks beams by means of timing to focus the beam at FE9. The energy of 132Sn (56Ni) transported to a reaction target locating in S0 focus is 50A MeV or slowed down to 20A, 10A or 5A MeV by another degrader at intemediate focus FE9. By means of this dispersion, the wedge-shaped energy degrader at FE9 is employed to compress momentum spread for low-energy beam. In this simulation, wedge angle of 12 mrad was used for both cases of 132Sn and 56Ni beam to optimize decelerations.

An energy degrader of Aluminum matching mono-energetic conditions are assumed to be installed at FE8 focus and calculated in simulation. After degrader to 50A MeV at FE8, beams are again degraded to 20A, 10A, 5A MeV by additional energy degrader at FE9 which has a wedge shaped geometery to compress energy-broadenings. Sets of simulated energy-degraders are in following list.

Deceleration	Degrader at FE8	Degrader at FE9
132Sn::50A MeV	9.40 mm w 28.5 mrad	---
132Sn::20A MeV	9.40 mm w 28.5 mrad	0.63 mm w 12 mrad
132Sn::10A MeV	9.40 mm w 28.5 mrad	0.77 mm w 12 mrad
132Sn::5A MeV	9.40 mm w 28.5 mrad	0.83 mm w 12 mrad
56Ni::50A MeV	8.85 mm w 29.0 mrad	---
56Ni::20A MeV	8.85 mm w 29.0 mrad	0.70 mm w 12 mrad
56Ni::10A MeV	8.85 mm w 29.0 mrad	0.84 mm w 12 mrad
56Ni::5A MeV	8.85 mm w 29.0 mrad	0.88 mm w 12 mrad

Specification of RF deflector.

Maximum high voltage	300 kV
Gap(horizontal)	200 mm
Width(vertical)	400 mm
Length of electrode	1200 mm
Frequency	18.5 MHz

▲ ▼

Energy broadenings

Energy distribution at S0 focus where a reaction target is assumed to be installed. 2ndary beams of 132Sn and 56Ni with energies of 250A and 210A MeV are degrade to 50A MeV due to large energy losses induced in thick energy degraders at FE8 focus, respectively.