[Hallb-engineering] HD-Ice run canceled

[burkert]

Dear Colleagues,

All shifts until the end of the scheduled run period until May 13 are 
canceled. Unfortunately, due to a problem with a critical needle valve 
the HD-Ice team was unable  to cool the magnet down to its operating 
temperatures. Attempts to unclog or otherwise fix the valve without 
fully warming up or opening up the IBC were unsuccessful. A complete 
warm-up and cool-down cycle would take over a full week making any 
attempt at repairing the offending valve within the available time an 
impossibility.

The plan now is to continue tests with the superconducting magnets and 
the new NMR system before warming the IBC up to room temperature and 
transferring it back to the HDIce Lab.
The long term plan is to have the IBC repaired a do some improvements on 
the cryogenics system where necessary. Then cool down the system in the 
Lab and be ready for an early installation in Hall B long before the 
machine comes backup after the 6 months shutdown. This should give us 
sufficient time to have a fully operating target long before the 
scheduled beam time begins in November 2011.

I like to thank the HDIce team and the Hall B staff for their dedicated 
efforts to get this complex new system operational in time.

Volker Burkert