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Ferrite Heating: Measurements in Clean Room. PT100 setup for installed MKI’s. PT100 on ground plate of magnet. PT100 on ferrite of “tube”. Magnet in vacuum tank; tank at atmospheric pressure; no bake-out jacket. Ceramic tube.
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Ferrite Heating: Measurements in Clean Room PT100 setup for installed MKI’s PT100 on ground plate of magnet PT100 on ferrite of “tube” Magnet in vacuum tank; tank at atmospheric pressure; no bake-out jacket. Ceramic tube Note: both PT100’s installed for measurement of magnet temperature, in clean room, gave same reading to within ± 4 ˚C. Conclusion: for measurements in clean room, Curie point of ferrite corresponded to 106 ˚C measured on ground plates (dissipation of 172W/m in “heater element”). SIS interlock presently 55 ˚C (see next slides). M.J. Barnes
Measurements in Lab (2007) 172W/m gave a temperature of ~108˚C, steady-state, which is close to the Curie Temperature of the ferrite (see previous slide). BUT… MKI was not under vacuum, did not have a bake-out jacket, ….. So, in reality, less than 172W/m would be expected to result in ~108˚C steady-state. Note: thermal time-constant for temperature increase: ~16hrs for magnet ferrite, & ~4-6hrs for tube. Note: thermal time-constant for temperature decrease: ~23hrs for magnet ferrite, & ~12hrs for tube.
Magnet Heating: Measurements during Operation 40 D5R8_dn: 38.2˚C (extrapolated max. 39.5˚C, τ=8hrs) D5R8_dn: 37.5˚C (extrapolated max. 42.8˚C, τ=8hrs) D5R8_dn: 37.5˚C B5R8_dn: 35˚C 35 30 B5L2_up: 29.2C 25 20 15 Wide range of magnet temperatures, and “up” & “down” can be quite different – poor thermal contact. Thermal time-constant of ~8hrs is approx. half that measured in lab (previous slide). M.J. Barnes