哈尔滨工程大学 RIBLL合作组会议@兰州 2013.08 宋玉收 14Be 库仑破裂实验准备 哈尔滨工程大学 RIBLL合作组会议@兰州 2013.08 宋玉收

内容提要 背景 事件产生与探测器建模 靶厚与PID讨论 实验事件预估 总结

库仑破裂研究丰中子核 库仑破裂应用 M. Labiche et. al, prl86.600.2001

14Be库仑破裂研究现状 S2n (exp.) and Rrms (exp.) → 实验数据有限，存在矛盾 数据与11Li、6He不同 S2n=0.9MeV S2n=1.34MeV

库仑破裂优势 针对滴线核束流弱，截面大； 外围碰撞，产物前向运动，可以前向角布置探测器； 实验装置示意图

Nuclear reaction in G4 G4 nuclear reaction models Binary Cascade Abrasion & Ablation QMD EMD Not feasible for our problem

Kinematics Pb Inelastic scattering Dissociation 14Be 14Be* 12Be 2n S2n 12Be+n+n Inelastic scattering Dissociation S2n 14Be

The inelastic scattering of 14Be on Pb target    

The breakup of excited 14Be    

12Be kinematic information 2n kinematic information  

14Be before EMD Reaction position Momentum direction Kinetic energy P z P

Position distribution M. Labiche et. al, prl86.600.2001 570mg/cm2 ~500 m

  r Z  

Spectrum Setting

Target thickness M. Labiche et. al, prl86.600.2001： 0.503 mm beam profile energy smearing (8MeV, ~1.6%) Incident direction Target thickness (mm) Ion telescope resolution Neutron wall resolution & threshold N Y 0.5 1.0 1.5 1.8

Influence on PID 12Be Time of Flight 14Be

Pb Target 0.5mm

incident TOF TOF&E-E 12Be 600,000 55911 54898 14Be 15,000,000 6441 1366 According to EMD cross section: (1)The purity of 12Be with the PID cut is 80%=54898/(54898+13660) (2)12Be loss rate because of E-E Cut is ignorable

Pb Target 1mm Particle Identification becomes more difficult

Pb Target 1.5mm

Pb Target 1.8mm

14Be 14Be* 12Be+n+n S2n      

PRELIMINARY Red: spectrum set Black: spectrum reconstructed Pb Target 0.5mm Red: spectrum set Black: spectrum reconstructed Pb Target 1mm

20Ne（80AMeV, 100enA） 200enA 的18O 作为入射初级束，3500um 的9Be 作为初级靶，降能器为2000um 的Al，分离提纯后的14Be，能量为35AMeV，能量展宽约8MeV（~1.6%），流强约为20 pps. 26.0/hour*100hour=2600

Summary M. Labiche et. Al (prl86.600.2001) chose the target with a thickness of 570mg/cm2 ~500 m; According to our simulation 1mm is still a feasible thickness; Thicker target will crack the reconstructed spectrum; To be done: Real three-body kinematic calculation; Create GEANT4 Physics process to handle EMD reaction of 14Be on Pb target; Considering optical process of neutron wall and CsI; Considering neutron wall in more detail;

谢谢！