1. Spectrometer Solenoid Update Steve Virostek - LBNL MICE Video Conference #129 February 25, 2010

2. Page2 Magnet 2 Modification Summary A modification to Magnet 2 has been carried out which adds a single stage cryocooler to provide additional cooling to the HTS leads and won’t require full magnet disassembly The single-stage Cryomech AL330 cooler provides 170 W at 55 K and required modifications only in the “turret” area The added cooling power should lower the HTS lead temperature sufficiently to train to full current The new cooler could remove enough heat to permit the other 3 two-stage coolers to maintain the cold mass LHe level (i.e. closed system) Additional instrumentation has also been incorporated

3. Page3 Magnet 2 with Added Cryocooler Single-stage cooler Thermal link HTS leads

4. Page4 Modification Details Added turret space Access port

5. Page5 Current Status of Magnet 2 The Magnet 2 turret area has been modified to allow installation of the single stage cooler New HTS and warm leads have been tested in an off line apparatus and have been installed in the magnet Additional temperature sensors on the cold heads (1 st and 2 nd stages) and voltage taps on the lower HTS leads have been added Initial pumpdown and leak check of the magnet insulating vacuum has been carried out Several leaks in the new turret welds were found and are expected to be repaired today Cooldown will start in one week if leak repairs go well

6. Page6 Magnet 2 Single Stage Cooler Single stage cooler and flexible copper thermal link during fit installation in Magnet 2

7. Page7 Vacuum Pumping of the Magnet Reassembled turret (single stage cooler on right) Mechanical pump with cold trap and increased diameter connection

8. Page8 Magnet Leads Testing A series of off line lead tests were conducted in order to characterize the warm leads and verify the performance of the HTS leads The tests were delayed by a vacuum leak in one of the ceramic feedthroughs that was not readily located The resistive heating in the warm leads was found to be higher than originally predicted; a modified design has been incorporated into Magnet 2 Lead tests for Magnet 1 are under way and near complete

9. Page9 Magnet Lead Test HTS lead 1 st stage plate Thermal connection

10. Page10 Installed Leads in Magnet 2