Dear spinlanders,
we experience a long lasting drift ( Hertz / hour is 4 times the max
allowed in the specs ) on a DMX 400. US
The magnet seems to be involved ( drifting extrapollates during power down
of all control units) but the Liquid helium evaporation rate remains normal ( )
An ice plug formed at the vent entry may have dropped down into the dewar
when extracting the frozen transfer pipes upon refilling .
No quench happened yet while the problem appeared just after the refill 4
weeks ago .
Is there a way to swirl liquid helium inside the dewar to try and move an
eventual ice block ?
i.e. overpressurized flushing of LHe ?
Any experience with such symptoms considered as unusual by Manufacturer's
support.
Salutations Cordiales / Best regards / ;-)
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Hervé Bizot / BIA-SASC / Inst. Nat. Recherche Agronomique /
rue de la Géraudière/ BP# 71627 /44316 NANTES Cédex 03 / FRANCE
Tel.: 33 (0)2 40 67 50 00 / FAX.: 33 (0)2 40 67 50 43 or 50 05 / E-Mail
hbizot_at_nantes.inra.fr
http://www.inra.fr
http://www.nantes.inra.fr/centre/unites-recherche/BIA/SASC/index.html
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Received on Fri Sep 02 2005 - 14:41:16 MST