Ferrite Heating: Measurements in Clean Room PT100 on ground plate of magnet PT100 on ferrite of “tube” Ceramic tube PT100 setup for installed MKI’s 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). LIBD: May 17, 20111M.J. Barnes Magnet in vacuum tank; tank at atmospheric pressure; no bake-out jacket.

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 D5R8_dn: 38.2 ˚ C (extrapolated max.  39.5 ˚C, τ=8hrs) B5R8_dn: 35 ˚ C B5L2_up: 29.2C 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). LIBD: May 17, 20113M.J. Barnes D5R8_dn: 37.5 ˚ C (extrapolated max.  42.8 ˚C, τ=8hrs) D5R8_dn: 37.5 ˚ C