TY - JOUR
T1 - A chopper system for shortening the duration of pulsed supersonic beams seeded with NO or Br2 down to 13 μs.
AU - Lam, Jessica
AU - Rennick, Christopher J.
AU - Softley, Timothy
PY - 2015/5/1
Y1 - 2015/5/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84930635853&partnerID=8YFLogxK
U2 - 10.1063/1.4921398
DO - 10.1063/1.4921398
M3 - Article
AN - SCOPUS:84930635853
SN - 0034-6748
VL - 86
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 5
M1 - 053108
ER -