adamp
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Posts: 14
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Post by adamp on Feb 2, 2021 15:12:10 GMT -5
Is there somewhere I could find a rough approximation for the temperature compensation coefficient or gain table for the 400 series HSE probes?
I can provide more specifics about the exact probes we are using if required.
We are trying to isolate sources of thermal error in our measurement setup and this information would be extremely helpful.
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adamp
New Member
Posts: 14
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Post by adamp on Feb 9, 2021 19:36:10 GMT -5
is the lakeshore team still on Christmas break?
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Post by Lake Shore Ryan on Feb 10, 2021 15:02:29 GMT -5
I wish we were still on break! Can't believe it's been a whole month already. Sorry we didn't get back to you, this one must have slipped by.
The gaussmeter applies temperature compensation by calculating the difference between our calibration temperature and the current measured probe temperature and then applying a gain factor accordingly.
Gain factor = 1 + (temperature coefficient x temperature difference)
The temperature coefficient is unique depending on the sensor in the probe and will generally be somewhere in the range of +/- 0.1% per °C
So as an example, if the probe was calibrated at 24°C and your probe was measuring at 29°C you would expect a +5°C temperature difference to be used.
If that particular probe had a -0.02%/°C temperature coefficient, the the gain factor for that temperature would be 1 + (-0.0002 x 5) = 0.999
This gain value would then be applied to the calculated field value.
Unfortunately, the unique values stored on your probe are not accessible by the user, but you could try calculating using typical values:
Typical calibration temperature: 23°C
Typical temperature coefficient of sensitivity: -0.04%/°C
If you are not having any luck using these numbers, then I would suggest sending a request to support@lakeshore.com for them to look up your probe serial number to see what values were programmed into its onboard memory.
Best of luck. Let me know if this was helpful.
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adamp
New Member
Posts: 14
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Post by adamp on Feb 10, 2021 17:16:42 GMT -5
Thanks for the reply, Ryan!
This is helpful information, it's good to know that I can get the calibration data for my probes.
Another question: is the temperature compensation gain constantly updated with current temperature or is there a frequency associated with how often the gain is adjusted?
Is there a recommended amount of time that you would recommend for letting probes equilibrate to a change in temperature?
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Post by Lake Shore Ryan on Feb 10, 2021 17:21:06 GMT -5
It's continuous, as temperature changes, so does the gain factor.
Just curious, what sort of temperature ranges and field ranges are you experiencing? It sounds like you might be doing some interesting things if you're asking these sorts of questions.
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adamp
New Member
Posts: 14
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Post by adamp on Feb 10, 2021 17:50:26 GMT -5
OK, that's good to know.
We normally measure fields in the 1.5-3T range and subject the probe to temperatures in the range of (+20C)-(+40C).
We control our magnet temperature quite precisely, less than 0.01C per data gathering period, and try to control probe temperature to within 0.25C over same data gathering period, yet we are seeing some significant field drift over the course of our data gathering.
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Post by Lake Shore Ryan on Feb 11, 2021 9:46:29 GMT -5
If you're willing to share your findings, I'd be happy to look into it further. There are other temperature dependent properties too, like zero field offset. Is the gaussmeter in a temperature controlled area? Or would it be seeing temperature changes too?
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