CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 1 HCAL SOURCE SYSTEMS SOURCE SYSTEMS STATUS Virgil Barnes Purdue University CMS HCAL, FIU Miami, February 26-26, 2005

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 2 HCAL SOURCE SYSTEMS  Fabrication of HE and HB air drivers is completed.  HF PSDs (electric motor, Mod III) are completed, also some older TSDs have been refurbished. BUT:  Engineer Paul Debbins’ report has several potentially useful suggestions for improvements. Generally applicable to both air and electric source drivers. May help with reel friction and/or safely allowable extension force on wire.

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 3 HCAL SOURCE SYSTEMS TSD retrofitted with Stainless steel slide sheet and Lower support wire 500 wire insertions: ~7.8 m plastic tube with tight coil at far end End of tube turnoff force set to 48 oz

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 4 HB, HE SOURCE SYSTEMS  Very little wear-product is seen. Substituting SS for the UHMWPE slide sheet seems to give lower and more consistent friction and, so far, no buildup of gummy spots on the slide sheet and no black powder fallling onto base plate.  Lower support wire should, in principle, help protect the source wire from buckling during extension. Usual force limit ~38-40 oz. We are testing with higher forces. Need to understand force limit vs. source wire life with the improved support wires.  Extended testing will be done at Purdue.  Very promising, so propose to retrofit these mods into several TSDs before shipping them to CERN next week for use at HB. Loading wires will require slightly more dexterity, but note the small retaining clip on the reel. Recent invention to make wire loading easier.  Will look for phosphor bronze or other non-magnetic lower support wires for the air drivers in 4T field.

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 5 HB, HE SOURCE SYSTEMS  These retrofits are not too difficult or time consuming. The only machining on existing drivers is to make the exit groove in the reel plate ~ 1 mm deeper.  Looking into a third modification, easily retrofitted, to replace the adjustable washer stack on the reel axle with a “crown nut” arrangement. For ease in adjusting the snugness of the reel against the slide plate.  All three retrofits can be done on the HE air drivers at CERN.  Some older TSDs at CERN (and at Texas Tech, Mumbai) still need to be sent to Purdue for more extensive refurbishment.  Retrofit and old TSD refurbishment costs look like M&O budget items.

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 6 HB, HE SOURCE SYSTEMS  Wire getting “stuck” during retraction, at H2 (Pawel’s report yesterday) is not fully understood. High enough friction to require hand-operation of the reel.  May be fixed by above improvements, IF due to reel friction and/or non-straightness of source wire. But MUST avoid any really bad source tubes, of which a number are known at H2.  New lower-support wire will isolate the spring fingers from the source wire. This eliminates wear on fingers and snagging source wire (one of the H2 episodes).  Should use a good dummy wire to find all tube lengths and “weed out” bad calorimeter source tubes, before using radioactive wires in SX5.

CMS HCAL, FIU Miami, February 24-26, 2005 Virgil Barnes, Purdue University 7 HB, HE SOURCE SYSTEMS  Good news: I established in November that 35-foot source wires are sufficient for HB PSDs, as well as for all other locations in HCAL.  Propose to make temporary brackets to mount HB PSDs at SX5 mezzanine:  Early mechanical tests of air driver and tube manifolds in situ.