Dan Bauer CDMS Collaboration Meeting February 11 2005

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Soudan Overview • Highlights of work since July 2004 meeting Ended R 119 on Aug 9 and warmed up Cryogenics upgrades Backgrounds, shield, veto upgrades DAQ/electronics/computer upgrades Three new detector towers • Short-term schedule IVC-OVC leak is fixed! Finish leak checks and cooldown Commission five towers Initial calibration data Begin Run 120 • Schedule for the rest of CDMS II Run through 2005 • Some issues to discuss this afternoon

IVC-OVC Leak Dan Bauer CDMS Collaboration Meeting February 11, 2005 • Massive leak discovered last Friday – – – Opened OVC/LN lids, restrained IVC can and pumped out Radial sealing o-ring broken at end of e-stem Replaced ‘in-situ’ (NOT EASY) Pumped IVC to 7 E-5 torr last night; leak checking this morning Will close OVC and pump out both IVC and OVC over weekend

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Cryogenics Upgrades • Cryo Cooler – Proved difficult and time-consuming to install on e-stem • Mechanical problems and electrical isolation – Finally finished in December, 2004 – Tested operation briefly last week • Vacuum – Tightened bath/OVC and IVC seals in tails – Added low-impedance tail pumpout • May reduce or eliminate ‘burps’, reduce Lhe consumption • New Ebox – Much better vacuum bulkhead connectors • But mechanical problems with box itself led to delays – Now installed and leak tight – Should allow routine connection of detector cables

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Cryo Pictures • Cryocooler and ebox

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Cryogenics Upgrades • Icebox – Added 600 m. K, and modified 4 K, IR shields • Shields not well sealed around towers • 600 m. K caused problems when it cut tower wires – Added 600 m. K, 4 K IR absorber paddles • Try to absorb any stray heat from e-stem – Installed more thermometry at 4 K • Si diode thermometer on each tower, 1 on 4 K flange • Si diodes on both 4 K and 77 K stages of cryocooler – Cleaned cans as best we could w/o disassembly • Removed discrete particles and a kevlar string – Checked alignment of cans • Within 0. 01” of where they were before

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Icebox Pictures • 600 m. K shield and 4 K shield/IR absorbers

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Cryogenics Upgrades • Transfer systems – Improved LN transfer efficiency (50 PSI dewars) – Will fix Lhe transfer line resistors (keep water out) – New, longer Lhe slow-transfer line • UPS – Have same UPS, but installed automatic transfer switch • Will buy diesel generator to backup crucial vacuum pumps • Intellution/APACs – New PCs • Some issues with mine networking – New version of software (compatibility with FNAL) – Better LR 700 interface – Improved historical record • Move variables, better sampling

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Backgrounds, Shield, Veto • Radon – Now have 6 purge tubes instead of 1 • Allows much better purge between icebox and mu-metal shield • Also can purge area of inner poly – Can insert sources along both c-stem and e-stem • Sources below and above level of detectors • Veto – Upper layers of veto removed and stored – Interference problems with paddles around cryocooler • Shield – Pb rings around stems notched for new tubes

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Radon Purge • White tubes (2 on each stem) purge between icebox and mu-metal can – These can also accept all radioactive sources • Yellow tubes (1 on each stem) purge inner poly shield region

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Electronics Upgrades • FEBs – Problems with new FEB power supplies, fans • Mostly sorted out but few spare FEBs or supplies available • RTFs – Small fraction of triggers not registering on some boards • Have one such board at FNAL to debug • Remote control/monitoring – New box installed to allow remote control/monitoring of FEB and RTF power supplies and FEB fans

Dan Bauer CDMS Collaboration Meeting February 11, 2005 DAQ and Computing Upgrades • DAQ – 5 tower DAQ working • Still some work to improve data writing and tracking • Need some work on detector tuneup software • Need some improvement in online diagnostics • Offline computing – Dark. Pipe processing works for 5 towers • But need some work on logistics – New SAC - 30 dual-cpu machines from FNAL • Not installed yet; need surface building upgrades • Should be ready in time for massive data sets • Networking – Movement on both upgraded LAN (Gig. E) and WAN (T 3) • Target date for T 3 is March 17 • Should improve speed to Soudan by at least x 4

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Five Towers (Finally) • Installation – Installed T 3 -T 5 in October/November – Had to repair T 3 Z 5 (tower wires cut by 600 m. K shield) – Also repaired T 1 Z 4 (side coax) • Blown coupling capacitor, probably from ESD • Installed copper grounding platform around icebox – T 1 Z 1 has only two functioning phonon channels • But charge channels should work => veto detector – Maintained Rn purge of inner can for the whole time – Installed 31 striplines (one for diode thermometry) • Electrical checkout – FEDUP works well at Soudan (thanks to Dennis) – A few detector I/O cables need modifications

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Detector Pictures • Tower 3 Face 5 repair

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Detector Pictures • ESD platform for work around icebox

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Short-term schedule Week of February 14 Close icebox and ebox again, after reconnecting stripline warm ends Redo detector checks. Recheck IVC-air, OVC-air, IVC-OVC; check fridge-IVC, fridge-OVC Begin LN cooldown Week of February 21 Electrical checks of detectors at 77 K Begin slow transfer and go to 4 K Begin cryocooler operation Make sure autofill systems working correctly Electrical checks at 4 K

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Short-term schedule Week of February 28 Clean mix, establish circulation and tune mix Reach base temperature Begin turning on T 1 Week of March 7 Continue turning on and tuning detectors Close shield and reinstall veto Rest of March Continue tuning detectors Take calibration data sets Prepare for WIMP search running April 1, 2005 Begin Run 120

Dan Bauer CDMS Collaboration Meeting February 11, 2005 2000 CDMS-II Schedule 2001 T 1 2002 T 1 UCB/Case T 2 2003 2004 2005 SUF T 1 -2 Soudan Select best detectors for T 3 -5; study any remaining detectors at TFs T 1 -5 Began Science Begin Soudan Science Full Science Running

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Some discussions for this afternoon • Soudan Operations – Detector tuning strategies and software – Best strategy to maximize WIMP livetime – Amount and type of calibration (gamma, n) • Analysis – Role of Pipefitter – Analysis code maintenance and FNAL reprocessing – Optimization of beta rejection, nuclear recoil acceptance – R 118 PRD content – When do we unblind for R 119?

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Some discussions for this afternoon • Detectors and Test Facilities – How can we use TFs to understand T 1 -T 5 at Soudan? • What improvements are needed to do this? – Is any detector fabrication justified under CDMS II? • Agencies have said we cannot use CDMS II $$ for future work! • Backgrounds – What tests can we do at Soudan to understand gamma, beta backgrounds? – What screening work falls within CDMS II? • Alpha, neutron counters at Soudan • Continued surface analysis • Some additional gamma screening

Dan Bauer CDMS Collaboration Meeting February 11, 2005 Some discussions for this afternoon • Cryogenics – Need to develop contingency plans for further leaks or failure to cool to base – Also need operational strategy in the cryocooler era • Collaboration – Do the video meetings work well enough? – How can we improve communication and documentation? – What can be improved for people at Soudan? • Other – Feel free to meet in parallel groups on any CDMS II issues – Reconvene in plenary session to discuss ideas at 4: 00

Dan Bauer CDMS Collaboration Meeting February 11, 2005 People do manage some amusements at Soudan! • Spicy Buffalo Wings/Hot peppers contest – Oh, this really hurts!