Chev
New Member
Posts: 6
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Post by Chev on May 7, 2019 13:55:42 GMT -5
Hi. I have been using a DT-670A1 SD with an 18"x1/4" LSC temperature probe. I am measuring liquid H2 in the 30K range. I am reading ~2K high I believe and am wondering if I might have improved accuracy with a shorter probe. Presently the probe is immersed in LH2 at the tip but is likely seeing H2 vapor at a slightly elevated temperature for the majority of the probe length. The tip is in the liquid. Would I be be measurabley better off with a shorter probe and reduced vapor region? Or is all that matters the tip of the probe?
Thanks.
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Post by Lake Shore Jeff M on May 10, 2019 11:26:46 GMT -5
Hello Chev,
I discussed your question with one of the scientist in our sensor engineering department and he feels that the answer depends on how you have the leads thermally anchored. Basically, if the leads are anchored to the wall of the tube with the LH2 so that it would be at the same temperature as the liquid. If that is the case, then a shorter length probe stem may produce a closer reading. If the leads are not anchored at the LH2 temperature point, he suggests that you give that a try before ordering a shorter probe.
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Chev
New Member
Posts: 6
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Post by Chev on May 10, 2019 13:48:54 GMT -5
Thanks Jeff. The probe is sealed off from the LH2/GH2 via a swagelok fitting and the 30AWG lead runs to a junction box. The wire sees only ambient conditions. The swagelog is ~1" from the leads.  |
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