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The IceTop component of IceCube

The IceTop component of IceCube. Perspective from the South Pole. Outline. Scientific goals Design IceTop sub-group: tasks and staffing Budget & schedule Status of test-tank deployment, 03/04 season Lessons from current season. IceTop: the surface component of IceCube.

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The IceTop component of IceCube

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  1. The IceTop component of IceCube Perspective from the South Pole Tom Gaisser

  2. Outline • Scientific goals • Design • IceTop sub-group: tasks and staffing • Budget & schedule • Status of test-tank deployment, 03/04 season • Lessons from current season Tom Gaisser

  3. IceTop:the surface component of IceCube • A 3-dimensional air shower array for • Veto (i.e. tagging downward events) • Calibration • Primary composition from PeV to EeV • Calibration, composition analyses similar to SPASE-AMANDA but • 5000 x larger acceptance • wider energy range, better resolution • IceTop at high altitude (700 g/cm2) • 125 m spacing between IceTop stations • Ethreshold ~ 300 TeV for > 4 stations in coincidence • Useful rate to EeV Tom Gaisser

  4. Showers triggering 4 stations give ~300 TeV threshold for EAS array Large showers with E ~ 100-1000 PeV will clarify transition from galactic to extra-galactic cosmic rays. Small showers (2-10 TeV) associated with the dominant m background in the deep detector are detected as 2-tank coincidences at a station. Detection efficiency ~ 5% provides large sample to study this background. Tom Gaisser

  5. IceTop station schematic • Two Ice Tanks 3.1 m2 x 1 m deep (a la Haverah, Auger) • Coincidence between tanks = potential air shower • Signal in single tank = potential muon • Significant area for horizontal muons • Low Gain/High Gain operation to achieve dynamic range Tank simulation with GEANT-4 Tom Gaisser

  6. IceTop tasks & activities • Design and construct tank detectors • Evenson, Shulman, McDermott, Roth, Stoyan, technician (TBH) • Deploy tanks • Gaisser, McDermott, Roth, technician (TBH) Yoshida (Chiba), student (UWRF), RPSC support, Engineer (SSEC) • Confirm dynamic range scheme for 2 DOMs • Bai • Calibrate detectors • Bai, Stoyan, Gaisser, Clem, Niessen, Spiczak (UWRF) • Develop and install DAQ firmware • Evenson, Seckel • Integrate DAQ software as part of IceCube • Seckel, Software engineer (TBH), Svarnkar (grad student), Asst Prof (TBH) • Simulations • Stanev, Niessen, Gaisser • Reconstruction, data handling • Tilav, Post-doc (TBH) • Physics analysis • All, including Asst Prof (TBH) Tom Gaisser

  7. Staffing plans • Current • 9 months faculty salary (includes 1 month UWRF) • 10 months technical staff • 5 months engineer • 50 months research scientists/post-doctoral (includes SPASE, which becomes part of IceCube in PY3) • 12 months grad student • Additional for PY03-PY10 • 4 months faculty salary (new Asst Prof) • 12 months entry-level technician • 12 months software engineer • 12 months post-doc for event reconstruction • 12 months for second grad student Tom Gaisser

  8. Budget • IceTop (1.3.2) is an integral part of IceCube • IceTop effort focused at Bartol/UD & UWRF • Air showers generate the primary background for IceCube as a neutrino telescope • Bartol/IceTop efforts (e.g. in simulation, DAQ, reconstruction, physics analysis) make substantial contributions to other WBS elements • 1.3.2 PY3: UD $1,086K; UWRF $60K; Total $1,146K • Other WBS elements in PY3: UD: $344K • Tank construction schedule: • 10+32 in PY3 then 32 each in PY4,5,6 then 22 in PY7 • This schedule allows shipping by vessel after PY3 Tom Gaisser

  9. Outline of Bartol/UD budget PY3 LaborCapitalMaterial & Supplies (includes shipping) 1.2.3.3 Field season ops $38K $20K 1.3.2.1 Tanks (10 + 32) 84 $250K 30 1.3.2.2 Cables (local coin only) 22 20 3 1.3.2.3 DOMs (labor only) 28 1.3.2.4 IceTop specific engineering 328 120 1.3.2.5 Integration of SPASE 90 10 1.3.2.6 Management/office 101 1.3.4.5 Test DAQ System 36 1.3.4.6 First deployment DAQ 8 1.4.3.1 Event generation 39 10 1.4.3.3 Detector simulation 33 6 1.5.1 Detector verification 50 1.5.2.1 Reconstruction 78 1.5.3.2 Calibration 26 Totals 961 296 173 $1,436K Tom Gaisser

  10. SPASE counting house South Pole 03/04 season Tom Gaisser

  11. Location of two test tanks, Nov ‘03 100 m Tom Gaisser

  12. Construction of tanks • 2 Tanks delivered to Bartol in July; plumbing assembled • Tanks & plumbing integrated, palletized and foamed at factory in VA late August • Tanks arrive at Pt. Hueneme Sept 2 Tom Gaisser

  13. Freeze-control equipment & DOMs • Freeze control assembled at Bartol August - October • Shipped with support equipment Sept-Oct (including sunshades) • 4 DOMs with rev2 boards assembled, tested, shipped from UW October 31 Two views of freeze-control equipment mounted on tank inside sunshade at site Tom Gaisser

  14. Reassembly at South Pole • Gaisser, McDermott, Roth arrive at South Pole Nov 10 • Used half of 40’x15’ heated Jamesway #76 in construction/cargo area • Uncrated and assembled tanks near Jamesway; location convenient to logistical support • Time: 2 persons, 1.5 weeks • DOMs arrive Nov 15 Tom Gaisser

  15. Preparation of site • In parallel with assembly • Locate & survey site • Excavating trenches: two hours using bulldozer with 14’ blade Nov 18 • Trenches 15 ft wide by about 40 ft long • Tanks separated by 10 m • Power cord from SPASE supplied by RPSC Nov 19 Tom Gaisser

  16. Transport to site • Nov 19 • Load tanks on sled • pull across skiway to MAPO • Forklift from MAPO to site • Level bottom of trenches • Set & level tanks • 3-man RPSC crew took a total of 2 hours Tom Gaisser

  17. Install freeze-control & DOMs • Tank10 (1.0 m ice) • Install freeze box • Install ejection pipe • Bring up software • Install DOMs • Nov 20-21 • Tank09 (0.9 m ice) • Same procedure • Nov 25-26 Tom Gaisser

  18. Fill tanks • Tank10 • Freeze up of hose on first attempt (Nov 21) • Successful fill Nov 22 • 20 minutes to fill • < 10 RPSC man hours for transport and filling • Tank09 • Filled Nov 26, very smooth operation Tom Gaisser

  19. Monitor freezing • Two days to freeze over • Frost-covered ice • Clear; wind 6-10 kts • T = -40 to -35 deg C • Ice-surface at -20 deg C •  37 days to freeze 1 m • But Tank10 at 2/3 ideal rate • Will reduce heat tape, pump cycle time, add fans to reduce freeze time • Tank09: problems with temp sensors currently being addressed. No water ejected after 100 hours suggests slow leak. To be investigated. Ice appears good. • Winter-over scientist will take over monitoring to bridge until arrival of next crew (J. Eisch, S. Yoshida) Tom Gaisser

  20. Remainder of season • Dec 1-5: train winter-over scientist (J. Lackey) and address problems • Dec 10-30: Monitoring continues • S. Yoshida, Dec 10-31; J. Eisch Dec 20-Jan 6 • Dec 29-Jan 20: Install DOM-DAQ • J. Kelley, A. Karle with Evenson & S. Tilav • Jan 12-27: Close tank • P. Evenson, Jan 12-27 Tom Gaisser

  21. Lessons so far • Modularize equipment • “plug and play” design to reduce labor needs • Programmable Logic Control to streamline assembly and operation • Should include temperature control of heat tape • Commercial OTS control units at each tank • See memo of Andrew McDermott based on experience this season • Manufacturing schedule should be at least one season ahead to allow shipping by vessel • Need full Jamesway (40 x 15 ft) for staging • Begin early in season with tank assembly • Counting house, surface cables required early to allow setting tanks • Tanks to be filled as soon as Rodriquez well for drilling is ready—should not wait to be filled as each hole is drilled. Tom Gaisser

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