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Spin Launch, pretty cool...............

davedude

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I've worked a long time in instrumentation and related fields and this statement stopped me cold (sorry). What is used to measure temperatures when you can see zero Kelvin from there? And what are the response times for process variable delta's like? Is it watch it happen, or, "we'll see what it is in a little while."
See zero kelvin? Not sure I understand. The sensors are some kind of diode coupled to a digital or analog display. All our cryopumps have them. Mounted on the cold head. Coldest temp I've been able to get is 11 kelvin. That is with a fresh regeneration and no gas or crazy heat load to mess it up.


From room temp to 14 kelvin takes several hours. Once cold they stay cold unless loaded with too much gas. Then a regen cycle is started to warm it up and pump out the captured gas.
We try not to slam them with high gas loads but shit happens sometimes ;-)
 

L Haney

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See zero kelvin? Not sure I understand.
What I meant was that close to zero K, (11 degrees above absolute) most electronics fail. Most temperature sensors depend on some current flow to function which means they will generate 'some' heat. Ain't much, but it's there. It can be cal'd out of the loop but depending on the process environment I could see that heat introduction being a problem. Mostly with very small mass and volume environments.
 

davedude

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What I meant was that close to zero K, (11 degrees above absolute) most electronics fail. Most temperature sensors depend on some current flow to function which means they will generate 'some' heat. Ain't much, but it's there. It can be cal'd out of the loop but depending on the process environment I could see that heat introduction being a problem. Mostly with very small mass and volume environments.
I suspect you are into far more accuracy than I am concerning the low temp measurement. ;-)
 

J308

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