1988 Fiscal Year Final Research Report Summary
Helium-filled proportional counter for low-temperture opration(1.5-4.2k) and its application to cryogenic resonance electron Mossbauer spectroscopy.
| Project/Area Number |
62460029
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
固体物性
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
ISOZUMI Yasuhito Radioisotope Research Center, 放射性同位元素総合センター, 助手 (50027603)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KATANO Rintaro Institute for Chemical Research, 化学研究所, 教務職員 (50231254)
ITO Shin Radioisotope Research Center, 放射性同位元素総合センター, 助手 (30144398)
|
|---|
| Project Period (FY) |
1987 – 1988
|
| Keywords | Proportional counter / Mossbauer spectroscopy / CEMS / Internal conversion electron / 固体物理学 / 放射線計測 / 低温放電 |
|---|
| Research Abstract |
In our previous works, the opration of the helium-filled proportional counter (HFPC) was investigated at low tempertures down to 5 K. It was found for the first time that the HFPC cooled at very low temperatures (near liquid-helium temperature, i.e., 4.2 K) works well in the proportional region, but with low gas gains below 200. A main purpose of the present work is to extend the HFPC technique to temperatures below 4.2 K and to apply it to the cryogenic resonance electron Mossbauer spectroscopy (REMS).
Using a new whole counter system with a metal dryostat and a HFPC specially designed for this work, we hver succeeded to detect electrons emitted from samples cooled at low temperatures (1.75-4.2 K). The lowest temperature we obtained by helium pumping is 1.75 K. New informations on the mechanism of the HFPC operation at such low temperatures have also been obtained: (1) The gas gain does not depent on the gas temperature. (2) The anode voltage to induce the continuous discharge becomes lower as the gas emperture is decreased.
The REMS measurements in the region below 4.2 K is now possible with the technique develiped by the present work. Many studies with the cryogenic REMS, e.g., corrosions on iron foil and ultra thin iron oxide layers, are now in progress in Radioisotope Research Center of Kyoto University.
|
