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22 Na+p 共振散射的厚靶实验研究

22 Na+p 共振散射的厚靶实验研究. 王 友 宝. 原子能院核天体物理组 2013 年 RIBLL 实验计划. Contents. Scientific Motivation CRIB experiment and result RIBLL experiment. Orgueuil meteorites and Ne-E problem.

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22 Na+p 共振散射的厚靶实验研究

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  1. 22Na+p 共振散射的厚靶实验研究 王 友 宝 原子能院核天体物理组 2013年RIBLL实验计划

  2. Contents • Scientific Motivation • CRIB experiment and result • RIBLL experiment

  3. 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 20Ne/22Ne 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)

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

  5. 22Na production somewhere The relatively short half-life and the 1.275 MeV g-ray make the 22Na a possibly sensitive probe for the diagnosis of nearby Nova outbursts from the Sun.

  6. International Gamma-Ray Astrophysics Laboratory European Space Agency http:// www.esa.int/science/integral

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

  8. 22Na g-ray observation COMPTEL aboard CGRO observed five nearby Ne-type novae 22Na: only an upper limit of 3.710-8 M⊙ of ejected 22Na by any nova in the Galactic disk. What happened to the 22Na?

  9. Classic Nova Thermonuclear outburst takes place on the surface of a white dwarf component in a close binary system Joséet al., APJ, 520:347-360(1999)

  10. Main nuclear paths in the synthesis of 22Na Four reactions that control the synthesis of 22Na: 20Ne(p,g)21Na 21Ne(p,g)22Na 21Na(p,g)22Mg 22Na(p,g)23Mg Joséet al., APJ, 520:347-360(1999)

  11. Narrow resonances rate entirely determined by “resonance strength” wgand energy of the resonance ER resonance strength (= integrated cross section over resonant region) (Gi values at resonant energies) • experimental info needed • partial widths Gi • spin J • energy ER

  12. CRIB 22Na+p experiment February 28-March 10, 2012 22Na beam production conditions

  13. 22Na RIB production At F3, with 50 kV of Wien Filter Purity: ~2×46.8 %

  14. Experimental setup at F3 chamber Gas target Length: 300 mm Windows: 2.5 mm Havar (front), 26.5 mm Mylar (back). Silicon Telescopes DSSSD+SSD 5050 mm2 22Na: 37.1 MeV (in gas) 2.5×105 pps (on target)

  15. Setup for 22Na+p/a PPAC Gas target H2: 310 torr He: 400 torr Ar: 75 torr 22Na

  16. a p d Light recoils from 22Na+p Proton spectrum from 22Na(p,p) and background

  17. Excitation function of 22Na(p,p)

  18. Multi-level R- matrix analysis

  19. Paper accepted for publication in PRC

  20. ST1 22Na+a Excitation Function ST2 ds/dW /mb/sr ST3 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！ Ec.m. /MeV

  21. 22Na+p with a solid (CH2)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23Mg激发能区，同时测量22Na(p,g)23Mg和19Ne(a,p)22Na感兴趣的23Mg能级。 • 比气体靶实验更简单易行。

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

  23. X-RAY BURSTERS & X-RAY PULSARS

  24. 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） 1H(22Ne, 22Na)n • 主束(22Ne7+) 能量：6.2 MeV/u；流强：~ 300 enA (RIBLL1入口) • 气体靶 氢气 [f30，80 毫米长，500 mbar大气压，酒精冷却～2C] • 次级束(22Na11+) • 纯度：30％，流强：1.7104 pps • 预期：1000 enA 22Ne, 1atm 氢气, 22Na流强可达 2105 pps

  25. RIBLL的22Na次级束流 • 束流粒子鉴别图 狭缝条件：C1:15 mm (DE/E=1.5%), C2: 10 mm (DE/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】

  26. 22Na次级束

  27. 实验设置 22Na: 93 MeV, Ec.m.≈ 4.0 MeV (CH2)n靶： 7.5 mg/cm2

  28. 谢谢大家！

  29. Beam size on target position by extrapolation

  30. 22Na(p,g)23Mg Reaction Rate

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