Direct measurement of 12C-4He fusion total cross section near stellar energy

2014 Fiscal Year Final Research Report

• Project/Area Number: 24340056
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Kyushu University
• Principal Investigator: SAGARA Kenshi 九州大学, 理学(系)研究科(研究院), 名誉教授 (00128026)
• Co-Investigator(Kenkyū-buntansha): FUJITA Kunihiro 九州大学, 大学院理学研究院, 助教 (60532364) ; TERANISHI Takashi 九州大学, 大学院理学研究院, 準教授 (10323495)
• Co-Investigator(Renkei-kenkyūsha): MORITA Kousuke 九州大学, 大学院理学研究院, 教授 (20250110)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 天体ヘリウム燃焼 / タンデム加速器改造 / 極微量粒子検出 / 極低バックグランド測定 / 窓無し気体標的 / 金箔皮膜

Outline of Final Research Achievements

In the sun 4He is being made from 4 protons. That is Hydrogen burning. In heavier stars, heavy elements up to Uranium are being made in succeeding processes of Hydrogen burning → Helium burning → Carbon and Oxygen burning → …. These processes can be simulated using many nuclear reaction rates. However, a basically important reaction rate of 4He+12C → 16O+gamma in Helium burning has not been measured yet in spite of experiments in half century in the world. The measurement is extremely difficult due to special nuclear reaction mechanism.
In our present study, we measured very small 4He+12C → 16O+gamma rate near stellar energy by remodeling the tandem-accelerator at Kyushu Univ. and developing new instruments and methods based on our original ideas. We succeeded in measuring the reaction rate 1.5 orders of magnitude smaller than the previous world record. The final goal can be achieved by progressing further 2.5 orders of magnitude.

Free Research Field

実験核物理