| Project/Area Number |
09554013
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Nagoya University |
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Principal Investigator |
MASUDA Kimiaki Nagoya Univ., Solar-Terrestrial Environment Lab., Associate Professor, 太陽地球環境研究所, 助教授 (40173744)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBAMURA Eido Saitama Pref. Univ., College of Health Science, Professor, 短期大学部, 教授 (30100605)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 1999: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥6,900,000 (Direct Cost: ¥6,900,000)
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| Keywords | Particle detector / Rare gas liquids / Energy loss / Heavy ion calorimeter / Isotope identification / 光電離 |
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| Research Abstract |
This research project aims to study the performance of liquid argon calorimeter with photoionization process in order to investigate the energy resolution and isotopes identification for high energy heavy ions.
We have measured responses of an allene-doped liquid argon calorimeter to heavy ions from HIMAC of NIRS, Japan. Electrodes of the calorimeter are made of thin G10 plates which are mechanically precise and form multi-parallel-plate ionization chambers. For measurement of position of incident ions and study of the effect of multiple scattering, two sets of strip electrodes are inserted to the electrode system. These give information of track of the particles.
Accelerator beams were 500〜650 MeV/n Ne, Ar and Fe ions and the beam intensity was 100〜200 counts per spill. In ionization chambers, induced charge signals are affected by space charge of positive ions. In general, the time structure of beam spills at HIMAC is not uniform. We used beams of more uniform structure and minimized the effect of space charge.
By adding allene, recombination of electron-ion pairs decreased and signal size increased. This led the improvement of energy resolution, but the resolution was still worse than that expected from calculation. This is the same if a specific scattering angle is selected.
This means that the scattering is not a main cause of degradation of resolution. This fact suggests that one must consider another effect such as density fluctuation of liquid. A scatter plot of signals of stopping cell and those of the preceding cell shows a clear separation of element but the isotope separation is critical. Further analysis will be done.
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