OxDEADBEEF
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Hi there,
does anyone have experience with amplifiers in cryostats? I would like to have one close to the sample inside the cryostat. The problem is that there will be at least 4T of field with large gradients and I guess that I have to insulate it. The sample is at 15Kelvin but I am thinking of running the amplifier around 100Kelvin to keep thermal radiation low, but silicon should still work. I would like to amplify frequencies between 0.1 Hz and maybe 50kHz but I can compromise somewhat on the bandwidth. HEMTs have terrible 1/f noise I was told. Did anyone ever attempt something like this, who can point me to parts that have worked for him?
Oh yeah and I need to use a Wheatstone bridge. I was thinking about a JFET as an adjustable reference resistor any thoughts on that?
does anyone have experience with amplifiers in cryostats? I would like to have one close to the sample inside the cryostat. The problem is that there will be at least 4T of field with large gradients and I guess that I have to insulate it. The sample is at 15Kelvin but I am thinking of running the amplifier around 100Kelvin to keep thermal radiation low, but silicon should still work. I would like to amplify frequencies between 0.1 Hz and maybe 50kHz but I can compromise somewhat on the bandwidth. HEMTs have terrible 1/f noise I was told. Did anyone ever attempt something like this, who can point me to parts that have worked for him?
Oh yeah and I need to use a Wheatstone bridge. I was thinking about a JFET as an adjustable reference resistor any thoughts on that?