Time‐resolved pulse‐counting lock‐in detection of laser induced fluorescence in the presence of a strong background emission
Time‐resolved pulse‐counting lock‐in detection of laser induced fluorescence in the presence of a strong background emission
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DOI：
10.1063/1.1147150
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发表时间：
1996-10
影响因子：
1.6
通讯作者：
B. Pelissier;N. Sadeghi
中科院分区：
文献类型：
--
作者：
B. Pelissier;N. Sadeghi
We describe a time‐resolved pulse‐counting system well adapted for the detection of continuous laser induced fluorescence (LIF) signals in repetitive phenomena, when a strong background emission is present. It consists of 256 channels coupled to a first in first out memory and interfaced to a 486 DX 33 PC, for data storage. It accepts time‐averaged count rates up to 450 kcount/s. Time between channels can be set from 12.5 ns to several μs and the dead time between two consecutive cycles of the physical phenomena is less than 20 ns. In phase with a chopper, which modulates the laser beam, it adds the observed photon signal to the channel memories when the beam is on and substracts it when the beam is stopped, acting like a lock‐in amplifier which detect only the modulated part of the signal. The minimum detectivity on the LIF signal is only limited by the shot noise of the plasma induced emission signal. As an application, we studied the time variation of the Ar+*(2G9/2) metastable ions, detected by LIF, i...
