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Curry-Jet SETUP

posted on 2019-01-04, 17:29 authored by Thomas ForstingThomas Forsting, Martin SuhmMartin Suhm
The "curry-jet" is a jet spectrometer setup combining spontaneous Raman scattering with a supersonic jet expansion.

The carrier gas (typically helium) is enriched by the desired substance in either a cryostatically cooled (S1) or a heated (S2) saturator system, depending on the vapor pressure and the desired concentration.
The mixture is supersonically expanded through a heatabe slit nozzle (N) from 0.1-1.3 bar stagnation pressure into the vacuum chamber at ca 1 mbar background pressure. A continuous operation is ensured by roots and rotary vane backing pumps in series with a maximum pumping speed of ca. 500 m3/h.
The expansion is probed 1-3 mm downstream the nozzle by a focussed (L1) 532 nm cw laser (Spectra Physics Millennia eV) with a maximum output of 25 W.
The scattered light is collected in a 90° angle with a standard 50 mm photo objective (O) as a collimator and focussed outside the chamber onto a 1000 mm monochromator with a 1340x400 px L-N2 cooled CCD detector (Princeton Pylon 400 B) attached to it.
This Raman spectrometer is used under non-resonant conditions and the good signal-to-noise ratio is accomplished by long integration times up to 10 minutes and averaging of multiple spectra.
Calibration is done with krypton and neon calibration lamps through the pinhole (PH).
Cosmic ray removal is achived by a script-based pixel-to-pixel comparison of multiple spectra.

The setup is under constant improvement, thus the presented scheme applies to group research from 2015 to 2018. Selected publications are mentioned below, for a more complete record, see:

(abbreviations used in the english version: BP - bypass, BS - beam stop, CV - check valve, EF - edge filter, L - focus lens, M - laser mirror, N - nozzle, O - objective, P - pressure gauge, PH - pinhole, S - saturator, SV - solenoid valve, W - window)


DFG SU 121/2

DFG SU 121/6