T. Gaisser, L3 Lead for 1.3.2 IceTop Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop IceTop functions 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 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

IceTop + IceCube: 1/3 km2 sr Coverage to EeV energy Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Veto, Calibration, Survey All downward events E > 300 TeV with trajectories inside IceTop vetoed Larger events falling outside also vetoed Tags 5% of m background in IceCube for study via ~3 TeV showers hitting stations Calibration of angular resolution with tagged m bundles Muon survey of IceCube Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Cosmic-ray physics IceTop EAS threshold ~ 300 TeV Knee of spectrum ~ 3 PeV Transition to extra-galactic CR may be below 1 EeV (HiRes, AGASA) IceTop – IceCube coincidences Measure spectrum, composition Locate transition to extragalactic CR Normalize potential extragalactic sources of high-energy neutrinos (see Halzen’s talk) Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Large showers with E ~ 100-1000 PeV will clarify transition from galactic to extra-galactic cosmic rays. Showers triggering 4 stations give ~300 TeV threshold for EAS array 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 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

EeV n Detection in IceCube with shower background Incident cosmic-ray nucleus n m Penetrating muon bundle in shower core Threshold ~ 1018 eV to veto this background Potential to reject this background for EeV neutrinos by detecting the fringe of coincident horizontal air shower in an array of water Cherenkov detectors (cf. Ave et al., PRL 85 (2000) 2244, analysis of Haverah Park) Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop IceTop Detector 2 m 1 m Diffusely reflecting liner Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop IceTop station Two Ice Tanks 3.1 m2 x 1 m deep (a la Haverah, Auger) Integrated with IceCube: same hardware, software 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 Two DOMs/tank also gives some back-up because only 1 low-gain detector is needed per station Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Technical requirements IceTop station must distinguish Random particles hitting one tank Small showers near one station Larger showers (4+ stations hit) Implications for DAQ Detector response Integrated signal = energy deposited independent of location in tank Time of 1st particle to < 10 ns Implications for ice quality, tank lining Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop DAQ design goals Feature recognition Low-gain / high-gain Local coincidence Horizontal showers Calibration mode Fully integrated with in-ice DAQ Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop IceTop DAQ components Monitoring DOMs (320) LG DOM Tank 1 Vert. Sh. Trigger InIce Trig.Gen. HG DOM Station 1 DOM Hubs (10) Hor. Sh. Trigger 10 Hz HG DOM Tank 2 IceTop Data Handler LG DOM IceTop Data Handler (IDH) IceTop Data Handler Station 2 Global Trigger DAQ Control 32 MB/s . 100 kB/s Common Event Builder Station 80 On line InIce DATA Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

IceTop FPGA Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop Projection of muon waveform onto four basis functions & reconstruction. High Trigger Rate + Bandwidth Constraints m: Advanced feature recognition e+ e– g: 2-tank coincidence Þ High Trigger Rate + Livetime concerns Þ 2-level trigger, fast ATWD decision 10 ns timing + synchronous trigger Þ Advanced feature recognition Date Task Resources 3/2002 Proof of concept 2001 test tank Altera dev. tools 11/2002 Practical Studies String 18 Data 2-5/2004 Digital Design UD: Bench test DOM UD: Test station Pole: 03/04 Tanks 5-8/2004 Implementation UD: bench & station 9/2004 -1/2005 Integration w/in-ice FPGA & DOM App Development: support from DAQ (1.3.3). Testing: at UD Projection of string-18 SPE waveform w/pedestal & reconstruction. Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

IDH and Trigger IceTop Data Buffer Global Trigger Jan 28, 2004 Monitoring Time Correction Time Control Separate Monitor Data In-Ice Trigger Create stream for “station hits” Create stream for “tank hits” Shower Trigger Trap calibration data Horiz. Shower Trig. Hubs DAQ Control IceTop Data Buffer Global Trigger Post trigger data retrieval Common Event Builder Online Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

IceTop DAQ Development Requirements Acquire Test Data Digital design Design Þ Firmware Bench test PY-03 Pole-DAQ Requirements Modify In-Ice DAQ Test at UD-station Review (9-1-04) Install & Test Deliver Pre-DAQ Design & Test FPGA IDH & Triggers Review Components Deliver algorithms/data formats/implementations FPGA 4 months IceTop DAQ v1 Initial Design Interface with In-Ice FPGA Implement and bench test SW – inc. IDH & Triggers Test at UD-station Assessment 8-31-2004 1-31-2005 } Acquire DAQ Simulation SPE, muon, shower High Gain, Low Gain Coincidence logic UD Test IceTop DAQ v1.1 Monitoring Calibration 5-31-2005 IceTop DAQ v2 Design Review Build Test at UD-station Station test at Pole Array test at Pole 7-31-2005 In-Ice/IceTop Integrated DAQ CONUS tests Tests at Pole Acceptance Milestone 2-28-2006 6-30-2006 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Detector design goals Primary: Produce blocks of clear ice approximately two meters in diameter by one meter deep. Each block is to be viewed by two optical detectors (DOM), which are to be “frozen in” to the ice. Secondary: Bottom and sides of the block of ice must be covered with a diffuse, highly reflective material. Entire assembly must be light tight. The entire assembly must be insulated to an R value of TBD to minimize the amplitude and suddenness of temperature variations Limit cracking of the ice Maintain optical coupling of DOM to ice Meet environmental constraints of the DOM. Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Detector construction plan Freezing based on natural ice growth on lakes. Clear ice is produced by a method known in the materials industry as “zone refining” which exploits the tendency of the crystal forming from the liquid phase to exclude impurities that concentrate in the remaining liquid. In a lake, the “impurities” (which include the oxygen fish need to survive) are diluted in the large volume of lake water under the ice. Top-down freeze allows accurate placement and “freezing-in” of DOMs at the outset Technical issues to be faced at Pole all derive from the need to conduct the freeze in a volume of water comparable to that of the end product. Remove expansion water as ice forms Keep dissolved air below saturation to avoid bubbles Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Status of detector development 2000-01: small tank at Pole Pressure relief via heated rod No degassing, no insulation 2001-02: full-size tank at Pole Pressure relief via heated pipe No degassing, no insulation. Freeze-time 28 days 2002-03: freeze 2 full-size tanks in commercial freezer in Delaware, one froze from top down, one from bottom up Both methods work Bottom-up requires cooling from bottom, DOMs freeze in at end Top-down requires degassing, pressure relief; DOMs freeze in initially, bottom can be closed from beginning 2003-04: freeze two full-size test tanks at Pole Insulated tanks assure uniform, flat freeze front, additional protection from thermal cycling. Achieve good ice quality but Freeze-time too long 2003… Construction of test stations in lab for calibration, testing Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop 2001 test tank Viewed by 2 AMANDA analog OMs Cloudy ice, asymmetric signals Currently taking data for comparison with station in lab Unsuitable as shower detector Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Design of prototype tanks; 8 to be deployed in 04/05 with 1st 4 strings Pallet Insulated tank DOM Support structure for DOMS and cover Freeze-control box* Pressure relief system Sunshade support* *Removed after freeze Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Degasser unit Dual unit: circulating pumps (black), filters (white) millipore degassers (outer units – connected to Vacuum ballast tank in freeze control box). Only one system at a time in operation. a) Before filling tank b) Near end of freeze under 85 cm ice Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Current test season at Pole Tank10 (1 m deep) Filled Nov 22, 2003 20 minutes to fill < 10 RPSC man hours for transport and filling Tank09 ( 0.9 m ) Filled Nov 26, 2003 Freeze time 60+ days 40 days planned mitigation options under study Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Freeze-rate Current test tanks have insulated sides, bottom Plot shows ideal time profile of ice thickness (m) Increasing ice thickness slows freezing Conditions in field complicated and variable during freeze Evaluation, analysis & modeling of freeze now in progress Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Cable runs looking toward MAPO away from SPASE Tank10 is on the right, Tank09 on the left. Power cable is on the left. There are 5 cables on the right: 2 freeze-control cables, two twisted quads for DOMS, and Stoyan’s cable to read temperatures during the winter. The latter is somewhat thicker than the other four. Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Tanks closed Jan 23-26 Tank10 during freeze and after closing b) Jan 23 after closing, tent used as outer cover over black vinyl sheeting a) Dec 6 during freeze (cover used as extra sun shade) Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

4 IceCube DOMs now running From: SMTP%"john.kelley@usap.gov" 15-JAN-2004 15:56:19.45 To: icecube-c@ssec.wisc.edu Subj: First Four IceCube DOMs Deployed I'm pleased to report that the first four IceCube digital optical modules have been successfully deployed at the pole. They are currently frozen into two IceTop surface tanks, located near the SPASE building. The DOMs are operating normally, and we are looking forward to dark-adapting the tanks and taking real data. John Kelley, UW-Madison ATWD waveforms in “scarface” --Serap Tilav, Jan 27 DOM frozen in place, Jan 15 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Schedule for tanks PY3 PY4 PY5 PY6 PY7 PY8 Strings deployed 4 12 16 18 18 12 Tanks Deployed: 8 24 32 36 36 24 Manufactured: 8 24 32 96 (accel) Freeze units (*) 8 (+2?) 16 (+2?) 12 0 manufctd (accel) Assumes each freeze unit reused up to 5 times. (add extras ?) Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Schedule Milestones Delivery of equipment for 03/04 deployment: 11/3/03 Post-deployment meeting: 3/27/04 Production readiness review for 8 prototype tanks: 6/15/04 Post-deployment meeting: 4/1/05 Second production readiness review 8/1/05 Initial In-Ice, IceTop Data System Integration Final Production readiness review 6/1/06 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Simulations For tank design & calibration Of electronics and DAQ For station design For array response and trigger Of air showers Coordinate with work under 1.4.3 for generation of background showers in deep detector Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Muon self-calibration procedure Vertical m (defined by m-telescope) In-tank coincidence (defined by 2 OMs) broadened m peak + low energy e-m background Data with test-tank setup at UD in water. (Large negative amplitudes on left.) Take in-tank coincidence data for each tank for commissioning Compare to lab template (in water) Interpret deltas with simulations Fix parameters for interpretation of signals Add to data base Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Initial calibration with SPASE SPASE will provide a tagged muon calibration and survey of first IceCube strings (before IceTop has enough detectors to reconstruct showers) SPASE will provide initial calibration of IceTop tanks SPASE: 30 m gridthreshold ~ 20 TeV Intermediate between 2-10 TeV of 2-tank IceTop station coincidence and 300 TeV IceTop array threshold Important energy region for background in IceCube (small showers with 2-3 muons) Sees IceCube strings from larger angle Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Hardware (capital) costs Tanks: 160 @ $6037 = $965,920 Frz units: 36 @ $6002 = 216,072 O’flow units 36 @ $ 561 = 20,196 Sunshade 36 @ $1922 = 69,129 Misc Tank Equip 38,550 Test station Equip (inc. $45K at UWRF) 75,000 4 test station tanks + ancillary equip 60,000 Computer cluster 180,000 Total capital $1,564,867 (+$60K) Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

Materials & supplies (inc shipping) + travel (both unburdened) 1.3.2.1 Tanks $ 18,850 (not enough for shipping) 1.3.2.4.1 (Test stations) 31,000 1.3.2.4.3 127,750 DAQ computers 27,000 move half to 1.3.2.1 Misc hardware 100,750 move to 1.3.2.4.1 1.3.2.5 -000- 1.3.2.6 48,000 (replacement work stns) Total M & S $225,600 Travel $549,000 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Labor Costs Total Labor cost for 1.3.2: $5.53 M Labor cost by Project year (burdened, $ M) PY 3 4 5 6 7 8 1.22 1.27 1.13 0.91 0.56. 0.44 Labor cost by WBS element ($ M) Tanks: $1.18 Cables: $0.30 DOMs: $0.22 Engineering resources: $1.32 Detector Simulations: $1.02 DAQ: $0.56 SPASE: $0.43 Management: $0.50 FTE years (by institution for total project) UD: 34.3, UW: 3.5, LBNL: 0.7, UWRF: 3.6 By Individuals involved part-time Scientists: UD:13 UW: 1 LBNL: 0 UWRF: 2 Engrs, techs: UD: 5 UW: 1 LBNL: 2 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Staffing Plan FTE per project year PY3: 7.5  8.8 Hire technician starting June 1 Part-time post-doc starting Sept 1 PY4: 8.8  9.4 Hire Junior faculty member PY5, 6 7 8 8.3 6.9 4.4 3.8 Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Issues/Risks Mitigation of slow freeze time Solution will ensure close-up on schedule Two options are available Speed up freeze Design for freeze to finish after closing Final plan likely to include aspects of both Redesign underway based on extensive information from current season’s test Aggressive initial hardware schedule: 8 tanks in 04/05, 24 tanks in 05/06 How to implement transition of effort to data handling, detector verification (and operations) as construction progresses Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop

T. Gaisser, L3 Lead for 1.3.2 IceTop Summary IceTop provides valuable calibration, survey and veto capabilities for IceCube. The possibility of a surface array over a n-telescope is unique to IceCube. The result is a kilometer-scale, three-dimensional air shower array, A novel tool for cosmic-ray physics to EeV energies with likelihood of significant discoveries related to neutrino astronomy Jan 28, 2004 T. Gaisser, L3 Lead for 1.3.2 IceTop