| Project/Area Number |
11650052
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied optics/Quantum optical engineering
|
|---|
| Research Institution | High Energy Accelerator Research Organization(KEK) |
|---|
Principal Investigator |
MIYAKE Yasuhiro KEK, Associate Professor, 物質構造科学研究所, 助教授 (80209882)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NISHIYAMA Kusuo KEK, Professor, 物質構造科学研究所, 教授 (50164611)
SHIMOMURA Koichiro KEK, Research Associate, 物質構造科学研究所, 助手 (60242103)
NAGAMINE Kanetada KEK, Professor, 物質構造科学研究所, 教授 (50010947)
MATSUDA Yasuyuki RIKEN, Researcher, ミュオン科学, 研究員
ストラッサー パトリック 理化学研究所, ミュオン科学, 契約研究員
パトリック ストラッサー 理化学研究所, ミュオン科学部門, 契約研究員
|
|---|
| Project Period (FY) |
1999 – 2000
|
| Project Status |
Completed (Fiscal Year 2000)
|
| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
|
|---|
| Keywords | Hyrdorgen / Lymanα Light / Lemanα / Difference Frequency / Resonant Ionization / Wave mixing / Deuterium / VUV / Laser |
|---|
| Research Abstract |
We have been pursuing an ultra-sensitive method for detecting and extracting hydrogen isotopes by utilizing a resonant ionization cheme via the {1S→2P→unbound} transition. A time-of-flight measurement using the pulsed lasers coupled with a mass separation device enables us to distinguish any hydrogen isotope with a very low background. By preparing a new "Slow Ion Optics" set-up to extract hydrogen isotope ions efficiently, the detection limit of the present method was improved to be much better than 3x10^3 cm^<-3>.
In the case of the laser induced fluorescence technique using Lyman-α or Balmer-α photons, the lowest detection limit is reported to be as low as the order of 10^7-10^9 cm^<-3>, or 10^7 cm^<-3>, respectively. In the case of the two-phone induced Balmer-α emission the detection limit is reported to be same order as that by three photon ionization, 3 X 10^9 cm^<-3>.
The detection limit of the present Lyman-α resonant ionization method can be evaluated by the following procedure
… More
. Assuming the probability of H_2 dissociation at the W surface at 2000 K to be 10% in 9.5 x 10^<-8> mbar of H_2 gas, about 3 x 10^7 H atoms exist in a volume of about 0.6 cm^3, which is the effective volume of extraction along the laser passage. Since we obtained an MCP signal of 4.5V with a temporal width of 80 ns at 2000 K, in contrast with that of 2 mV with 20 ns for a signle event, we can evaluate the number of 9000 H atoms per laser pulse that are extracted at 2000 K.From this, the extraction and detection efficiency is calculated to be 3 x 10^<-4>. Since the residual gas is not likely to be completely consisted of hydrogen molecules, the detection limit of the present Lyman-α resonant ionization method is estimated to be better than 3 x 10^3 cm^<-3>. It is thus 3 - 5 orders of magnitude better than the other methods. And also it is improved at least more than 2.5 times compared with that of our previous report and it is highest that we know of. The method of applying Lyman-α resonant ionization spectroscopy can be recognized as an ultra sensitive and efficient mass-selection technique. Less
|
