Makara, Aug. 17, Cryo Dept. Shutdown Status

Makara, Aug. 17, Tevatron at LN2 temperature except C4 and D1 at room temperature. –E1 warmup to room temperature started. –Tunnel magnet cryostat vacuums at A25 and D35-36 regions are of concern. –Pbar Cryogenic Transfer Line AP30-AP10/60 vacuum leak checked fine. –CDF back on their BA-1 Mycom compr (failed unit was replaced) and thus isolated from Tevatron Cryogenic System.

Makara, Aug. 17, Current Operations 3 FRIG Mycom comprs (plus DZero & CDF Cryo) running with helium precooled to LN2 temperature flowing through magnet strings. CHL helium inventory management system operating (Tank Farm, Helium Purifier, A0 GHe Recovery) and Tank Farm has been purified; helium losses normal. CHL Nitrogen Reliquefier plant off and LN2 supply dependent on vendor deliveries to CHL LN2 dewar tanks; deliveries are fine.

Makara, Aug. 17, FRIG Maintenance in progress –9 of 13 wet expander flywheels have been replaced –7 of 26 wet/dry expander overhauls of cold ends are completed –Tevatron Cryogenic Transfer Line F2-F3 vacuum being leak checked. –Various vacuum, instrumentation, and controls problems being worked on. CHL Maintenance in progress –Coldbox-1: Oil coolers have been replaced Charcoal Adsorber east unit is in high temperature regeneration –Nitrogen Reliquefier plant maintenance in progress: Marley Cooling Tower cleanup/overhaul, Rotoflow compr aftercooler heat exchanger tube bundle being replaced –Various facility maintenance in progress