A rugged, high precision capacitance diaphragm low pressure gauge for cryogenic use.

In order to carry out precise laboratory measurements of infrared absorption intensities, line profiles of molecules and organic volatile compounds for atmospheric chemistry in planetary and upper earth atmospheric layers, precise gas pressure measurement between 10(-3) and a few mbars in the 77-300 K temperature range is necessary. A prototype, rugged, precision capacitive pressure gauge for cryogenic use has been designed, built at SOLEIL and tested down to 77 K. The design includes corrosion-resistant materials and has been tailored to operate on a differential measurement scheme based on a simple, precision capacitance-to-digital converter chip, instead of high precision floating capacitive bridges, as are used in other designs.

A new, low temperature long-pass cell for mid-infrared to terahertz spectroscopy and synchrotron radiation use.

A new cell has been designed for accurate spectroscopic measurements in the 80-400 K temperature range with variable path lengths from 3 to more than 141 m. The spectral coverage at these temperatures ranges from the visible to less than 10 cm(-1), thanks to the use of diamond windows. The design of the cryostat and vacuum setups allows vibration-free operation.