concerning my question with respect to the installation of cryoprobes
I got two very useful responses.
The idea to solve the installation problem is simle:
- install the compressor nearby the spectrometer
- install a heat exchanger for a separate water cooling
system (it's much easier to transport water over a distance
of 70 meters instead of pressurized helium)
As a last remark it seems to be comparative easy to suppress the noise
of the compressor.
Once again many thanks.
Rainer Haessner