| Autor: |
Lam, Jessica, Rennick, Christopher J., Softley, Timothy P. |
| Předmět: |
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| Zdroj: |
Review of Scientific Instruments; May2015, Vol. 86 Issue 5, p1-7, 7p, 1 Color Photograph, 2 Diagrams, 4 Graphs |
| Abstrakt: |
A chopper wheel construct is used to shorten the duration of a molecular beam to 13 µs. Molecular beams seeded with NO or with Br2 and an initial pulse width of ≥200 µs were passed through a spinning chopper wheel, which was driven by a brushless DC in vacuo motor at a range of speeds, from 3000 rpm to 80 000 rpm. The resulting duration of the molecular-beam pulses measured at the laser detection volume ranged from 80 µs to 13 µs and was the same for both NO and Br2. The duration is consistent with a simple analytical model, and the minimum pulse width measured is limited by the spreading of the beam between the chopper and the detection point as a consequence of the longitudinal velocity distribution of the beam. The setup adopted here effectively eliminates buildup of background gas without the use of a differential pumping stage, and a clean narrow pulse is obtained with low rotational temperature. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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