22 Na+p 共振散射的厚靶实验研究 原子能院核天体物理组 2013 年 RIBLL 实验计划 王 友 宝

Contents Scientific Motivation CRIB experiment and result RIBLL experiment

Orgueuil meteorites and Ne-E problem Fell on May 14, 1864, a few minutes after 8 pm, near Orgueuil in southern France. About 20 stones fell over an area of several square miles. In 1972 ， Black found that in Orgueuil meteorites the abundance ratio of 20 Ne/ 22 Ne is less than 1.5 ， much lower than that of 9.8 on earth, this is the so-called Ne-Extraordinary problem 。 Geoch. Cosmochim. Acta V36, 347(1972)

Presolar grains separated from meteorite SEM-Secondary electron image S. Amari, ApJ690:1424–1431, 2009

22 Na production somewhere The relatively short half-life and the MeV  -ray make the 22 Na a possibly sensitive probe for the diagnosis of nearby Nova outbursts from the Sun.

International Gamma-Ray Astrophysics Laboratory European Space Agency

Milky Way seen by 26 Al  -ray at satellite observatory INTEGRAL observatory total of about 2.8 solar masses of 26 Al in our galaxy

22 Na  -ray observation 22 Na: only an upper limit of 3.7  M ⊙ of ejected 22 Na by any nova in the Galactic disk. COMPTEL aboard CGRO observed five nearby Ne-type novae What happened to the 22 Na?

Classic Nova Thermonuclear outburst takes place on the surface of a white dwarf component in a close binary system José et al., APJ, 520: (1999)

Main nuclear paths in the synthesis of 22 Na Four reactions that control the synthesis of 22 Na: 20 Ne(p,  ) 21 Na 21 Ne(p,  ) 22 Na 21 Na(p,  ) 22 Mg 22 Na(p,  ) 23 Mg José et al., APJ, 520: (1999)

resonance strength (= integrated cross section over resonant region)  i values at resonant energies) rate entirely determined by “resonance strength”  and energy of the resonance E R experimental info needed  partial widths  i  spin J  energy E R Narrow resonances

CRIB 22 Na+p experiment 22 Na beam production conditions Primary beam 22 Ne 7+ Energy6.1 MeV/A Intensity500 enA Production reaction 22 Ne(p, n) 22 Na Production target 1 H gas, 1.15 mg/cm 2 (LN 2 -cooled, 400 Torr, 90K, 80 mm in length February 28-March 10, 2012

22 Na RIB production Purity: ~2 × 46.8 % At F3, with  50 kV of Wien Filter

Gas target Length: 300 mm Windows: 2.5  m Havar (front), 26.5  m Mylar (back). Silicon Telescopes DSSSD+SSD 50  50 mm 2 Experimental setup at F3 chamber 22 Na: 37.1 MeV (in gas) 2.5×10 5 pps (on target)

Setup for 22 Na+p/  22 Na PPACGas target H 2 : 310 torr He: 400 torr Ar: 75 torr

Light recoils from 22 Na+p p  d Proton spectrum from 22 Na(p,p) and background

Excitation function of 22 Na(p,p)

Multi-level R- matrix analysis

Paper accepted for publication in PRC

E c.m. /MeV d  /d  /mb/sr ST1 ST2 ST3 22 Na+  Excitation Function 激发能区太窄，并且发 现使用气体靶会导致较 大几何不确定性！

22 Na+p with a solid (CH 2 ) n target 固体靶的优势 反应点的几何不确定性小，因此在低能段更准确。 能够覆盖更宽的 23 Mg 激发能区，同时测量 22 Na(p,  ) 23 Mg 和 19 Ne( ,p) 22 Na 感兴趣的 23 Mg 能级。 比气体靶实验更简单易行。

Motivations of another 22 Na+p measurement To study the relevant resonances in 23 Mg over larger excitation energy region using 22 Na+p channel with a well-developed thick target method To study the 23 Mg energy level related to the 19 Ne( ,p) 22 Na reaction

X-RAY BURSTERS & X-RAY PULSARS

RIBLL1 －低能次级束测试 参照东京大学 CRIB 装置，在 RIBLL1 上加装气体靶。 产生反应（逆运动学） 1 H( 22 Ne, 22 Na)n 主束 ( 22 Ne 7+ ) 能量： 6.2 MeV/u ；流强： ~ 300 enA (RIBLL1 入口 ) 气体靶 氢气 [  30 ， 80 毫米长， 500 mbar 大气压，酒精冷却～ 2  C ] 次级束 ( 22 Na 11+ )  纯度： 30 ％，流强： 1.7  10 4 pps  预期： 1000 enA 22 Ne, 1atm 氢气, 22 Na 流强可达 2  10 5 pps

束流粒子鉴别图 狭缝条件： C1:  15 mm (  E/E=  1.5%), C2:  10 mm (  E/E=  1.0%) TOF1 计数率： 46 万每秒 TOF2 计数率： 7.6 万每秒 T1 － T2 传输效率： 17 ％ } 【参见： J.J. He et al., NIMA680(2012)43-47 】 RIBLL 的 22 Na 次级束流

22 Na 次级束 Primary beam 22 Ne 8+ ， 8.2 AMeV Intensity500 enA Production reaction 22 Ne(p, n) 22 Na Production target 1 H gas, 0.81 mg/cm 2 (Alcohol-cooled, 1 atm, -30  C, 80 mm in length

实验设置 22 Na: 93 MeV, E c.m. ≈ 4.0 MeV (CH 2 ) n 靶： 7.5 mg/cm 2

谢谢大家！

Beam size on target position by extrapolation

22 Na(p,  ) 23 Mg Reaction Rate