Very cold!  The lowest temperature I ever worked with was that of dry ice 
(about -78C?)  

73
John

On 2 Oct 2011, at 08:45CEST, <[email protected]> wrote:

> Yes ,
> 
> hf is used for more things than amateur radio communication.The filters are
> used to read out a infrared detector-arrey(freq multiplexing).Workingtemp of
> detector,filters and preamp is 50 mK.(detectors and squid preamp don't work
> at all at higher temp).Very strange techniques but they do work.
> 
> 73
> 
> Victor