High-voltage calibration

Fig. 18. Schematic of apparatus used to measure fluorescence kinetics with a streak camera. The Nd glass laser emits a train of one hundred 1.06 pm pulses separated by 6 ns. A single pulse in the earlier portion of the train is selected by a Pockels cell and crossed polarizers (Pi and P2). The high voltage pulse ( 5 ns) at the Pockels cell is supplied by a laser triggered spark gap and a charged line. The single pulse ( 8 ps, 109 W) can be amplified. The second harmonic is generated from a phase matched KDP crystal. Beam splitters provide two side beams beam (1) triggers the streak camera beam (2) arriving at the streak camera at an earlier time acts as a calibrating pulse. The main 0.53 pm beam excites the sample for fluorescence measurement. The fluorescence collected with f/1.25 optics is focused into the 30 pm slit of the streak camera. The streak produced at the phosphorescent screen is recorded by an optical multichannel analyzer. (After ref. 67.)...

The block scheme of a Mossbauer spectrometer. A, absorber CR, cryostat with temperature controller TC (optional, for low-temperature measurements) S, source moved by velocity transducer VT of driving unit DR FG, function generator VC, velocity calibrator (optional) LI, laser interferometer (optional) DET, detector HV, high-voltage power supply PA, preamplifier AM, amplifier SCA, single channel analyzer MCA, multichannel analyzer and PC, computer, OP, output... 

The considerable Doppler shift in all collinear-beam experiments has opened up a few general applications beyond the spectroscopy of particular atomic or molecular systems. The scope of such applications ranges from simple beam velocity analyses to precision experiments related to metrology or problems of fundamental physics. These latter include the calibration of high voltages and measurements of the relativistic Doppler effect, for which the atomic transition frequency provides an intrinsic clock. 

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