Direct measurement of Nuclear Fusion Cross Section at Stars.

直接测量恒星的核聚变截面。

基本信息

批准号：
15104004
负责人：
SAGARA Kenshi
金额：
$ 73.47万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (S)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15104004/
关键词：
Helium burning in stars Thermal nuclear fusion in stars evolution of star very low background experiment tandem accelerator beam pulsation windowless gas target 窓なし気体標的冷却天体熱核融合反応長時間チョッパー加速器改造ヘリウム燃焼直接測定

项目摘要

Cross section of ^<12>C+^4He->^<16>O+γ reaction at Ecm = 0.3 MeV plays a crucial role in nuclear synthesis in stars, and measurements of the cross section have been attempted for about 40 years in the world However, the cross section has not measured yet since the experiment is extremely difficult. We have prepared the measurement of ^<12>C+^4He->^<16>O+γ reaction cross section at Kyushu University tandem laboratory for 15 years. In our method, we detect ^<16>O from inverse kinematics 12C+4He >16O+γ reaction at Ecm = 2.4 -0.7 MeV, and extrapolate the cross section down to 0.3 MeV. This is only one method to arrive the goal, but there are many difficulties. In 2004, we first succeeded in detecting ^<16>O from ^<12>C+^4He->^<16>O+γ reaction at Ecm = 2.4 MeV, although absolute value of the cross section could not be obtained.To arrive the goal, we need a)C beam intensity of more than 5 μA, b)He windowless target of 25 Torr x 3cm, c)background(BG)level below 10^<-19>, d)pulsed beam, e)stab … More le RF power supply of 2-6 MHz, f)optimized slit system of a recoil mass separator, and g)extrapolation method. Already we have pulsed the beam. BG level is now 10^<-17>, and remaining BG is to be found below Ecm = 1.2 MeV. In 2007, progress was made in a), b), and e)-g). We succeeded in preparing a He windowless target of 25 Torr x 3cm. The windowless target is 5 times thicker than those in the past. For a) and e)-g), we made concrete plan and 60-80% have been finished in 2007.In 2007, we made system check by measuring ^<12>C+^4He->^<16>O+γ cross section at 2.4 MeV, and found new BG produced by scattering of secondary beam halo at fixed slit in the recoil mass separator. By this trouble, experiment at 1.5 MeV was postponed to 2008. At Ruhr University, Germany, ^<12>C+^4He>^<16>O+y cross section has been measured at Ecm = 5.0-1.9 MeV. Owing to the preparation made in this research project, grant-in-aid, we will be able to make the ^<12>C+^4He->^<16>O+y experiment at Ecm= 1.5-0.7 MeV in 2008-2011, and arrive at the goal. Less

^<12> C+^4He->^<16> O+γ反应的横截面在ECM = 0.3 MEV在恒星的核合成中起着至关重要的作用，并且在世界上尝试了大约40年的横截面测量值，但是，自实验非常困难以来，横截面尚未测量。我们已经准备了^<12> c+^4he->^<16> O+γ的反应，在九州大学串联实验室已有15年的时间。在我们的方法中，我们从逆运动学12C+4HE> 16o+γ反应中检测到 ^<16> o，ECM = 2.4 -0.7 MEV，然后将横截面推断至0.3 meV。这只是到达目标的一种方法，但是有很多困难。 In 2004, we first succeeded in detecting ^<16>O from ^<12>C+^4He->^<16>O+γ reaction at Ecm = 2.4 MeV, although absolute value of the cross section could Not be obtained.To arrive the goal, we need a)C beam intensity of more than 5 μA, b)He windowless target of 25 Torr x 3cm, c)background(BG)level below 10^<-19>, d）脉冲梁，e）刺...刺...更多的2-6 MHz电源供应，f）优化的后坐力质量分离器和g）外推法。我们已经脉冲了光束。 BG水平现在为10^<-17>，剩余的BG在ECM = 1.2 MEV以下找到。 2007年，在A），B）和E）-g中取得了进展。我们成功地准备了25台3厘米的无窗目标。无窗目标比过去厚5倍。对于a）和e）-g）了，我们制定了混凝土计划，并在2007年完成了60-80％。在2007年，我们通过测量^<12> c+^4he->^4he->^<16> o+γ横截面在2.4 MeV处进行检查，并发现了新的BG，发现新的BG是通过在固定静置液体中散射在固定液孔中，在回流中固定的静脉液孔散射。由于这种麻烦，MEV的实验被推迟到2008年。在德国Ruhr University，^<12> C+^4He>^<16> O+Y横截面已在ECM = 5.0-1.9 MEV上测量。由于该研究项目的准备工作，我们将能够在ECM = 1.5-0.7 MEV在2008- 2011年进行^<12> c+^4he->^<16> o+y实验，并实现目标。较少的