Uppsala, Oct. 9, 2004 Tom Gaisser 1

IceTop Collaboration

Meeting

IceTop

• IceTop station• 2004 test tanks• Calibration• Verification 04/05• DOM operation• Summary• (Season plan)

Uppsala, Oct. 9, 2004 Tom Gaisser 2

IceTop Collaboration

Meeting

IceTop DAQ must capture three classes of events in 04/05:

• Single particles (low-energy e±, , for tank calibration)– Remnants of low energy interactions– ~ 2.5 kHz for 30 MeV threshold (10 pe)– Muons deposit 200-300 MeV (70 pe)

• Small showers (few TeV for tagging single in deep-ice)– Typical source of background in deep detector (E ~ 0.5 TeV

initially)– 10-20 m footprint on ground

• Coincidence between two tanks at a station• No signal in neighboring stations• No IceTop trigger• Check each in-ice event for such surface activity

• Large showers that trigger IceTop (E > 300 TeV for air showers and muon bundles in deep-ice)

– 3 or 4 stations hit in ~300 ns window– Primary energy up to 10^7 GeV with 4 stations

• [ Horizontal multi-m events (later in year or next season) ]

Uppsala, Oct. 9, 2004 Tom Gaisser 3

IceTop Collaboration

Meeting

IceTop Detector

2 m

0.9 m

Diffusely reflecting liner

Uppsala, Oct. 9, 2004 Tom Gaisser 4

IceTop Collaboration

Meeting

Two DOMs: 10” PMTOne high-gain; one low-gain in each tank

To DAQ

IceCubeDrill Hole

10 m

HG HG LGLG

Junction box

25 m

IceTop station

• Two Ice Tanks 2.7 m2 x 0.9 m deep (scaled-down version of Haverah, Auger)• Integrated with IceCube: same hardware, software• Coincidence between tanks = potential air shower• Local coincidence with no hit at neighboring station tags muon in deep detector• Signal in single tank = potential muon• Significant area for horizontal muons• Low Gain/High Gain operation to achieve dynamic range• Two DOMs/tank gives redundancy against failure of any single DOM

because only 1 low-gain detector is needed per station

~ 5-10 TeV

Uppsala, Oct. 9, 2004 Tom Gaisser 5

IceTop Collaboration

Meeting

Feb 10/11, 2004

Tank 9 with telescope Tank 10

12

3

4 5

6

Tank10 Temperature Sensors9 F

eb 0

4

9 A

pr 0

4

19

May

04

5

4

1,2,3,6

Tank9 DOMs

Tank10 DOMs

indicates cold start

air

DOM MainBoard Temperatures

18

Jul 0

4

Note that

-Tank9 is still 3 deg colder than Tank10 - MB temps 10 deg warmer than ice in normal operation- Glass temp tracks MB temps, warmer by only 5o

- Glass and MB reaches ice temps at cold start- Tankice temps 6 deg warmer than snow- snow temps 10 deg warmer than air

http://icecube.bartol.udel.edu/DOMMonitor/DOMTemps.html

8 S

ep 0

4

3 O

ct 0

4-55o

Uppsala, Oct. 9, 2004 Tom Gaisser 7

IceTop Collaboration

Meeting

Tank 2001 (buried under snow—different temperature sensors)

2001 Tank Temperatures

-80

-70

-60

-50

-40

-30

-20

-10

0

Date

Te

mp

(C

)

T airT1T2T3T4T5

VEM

Uppsala, Oct. 9, 2004 Tom Gaisser 9

IceTop Collaboration

Meeting

Tank calibration & monitoring

• Use characteristic spectrum with muon peak and high-energy tail– Requires calibration data stream– Requires lab station for data template

(two water tanks at UD)– Requires detailed simulations of

response of tanks to• Photons• Electrons• muons

Uppsala, Oct. 9, 2004 Tom Gaisser 10

IceTop Collaboration

Meeting

Test tanks for calibration:Full station at UD, 1 tank at UWRF

Test tank at UWRF with AMANDA OMs

Fig 1

John Clem, FLUKA

Fig 4

Set discriminator threshold here

John Clem, FLUKA

The simulation results are shown as histograms. The dashed green histogram is proton fluxes determined with a higher modulation level primary spectrum. Solid red circle is Bai et al. 2001 measurement. All other data shown is from Grieder 2001. The dashed red line muon measurement at 3250 meters elevation and solid red is 2960 meters. Red diamond 700mbar pressure. Black line is gammas at 750mbars (measurement at unknown geomagnetic cutoff and mod level) . Green line is protons at 3250 meters and green circle at 700g/cm2 (cutoff and mod level unknown)

John Clem, FLUKA

Comparison with measured flux

Uppsala, Oct. 9, 2004 Tom Gaisser 14

IceTop Collaboration

Meeting

Verification 04/05

• Obtain charge spectrum from high-gain DOM in each tank

• Obtain rates of station hits and coincidences– station hit = both tanks hit within 100 ns– 1-folds, 2-folds, 3-folds, 4-folds in 500 ns

• Zenith and azimuth distributions• Coincidence rates with deep detector

Simulated response of single station hits (mostly single muons in deep ice)

Low coincidence rate is due to 4-string geometry, < 6o in ‘05

Core location distributions, Ep =18 TeV

Core locations for Ep = 2.7 PeVNote that ring of distant singles from PeV showers will be removed by surrounding stations in larger array

Ep, cos() distributions of 4-folds3-fold rate ~ 0.30 Hz

0o

90o

Azimuthal distributions

Spectrum of deposited energy for 4-fold events

(VEM*factor)

13,24

-200,-220

210,220

-53,-71

Numbers in boxes show hit times in ns relative to core time of ideal shower plane

IceTop DOM settings

Set voltages so peak is centered on ATWD0 of HG DOM and onATWD2 of LG DOM

Require local coincidencebetween tanks to keep data rate low

Short calibration runs to collect single tank particle spectra

Uppsala, Oct. 9, 2004 Tom Gaisser 23

IceTop Collaboration

Meeting

Summary

• We are on track for 8 tanks in PY3• Ongoing temperature measurements

clarify operating range for IceTop DOMs• Operation of DOMs requires

– Local coincidence (or high threshold)– Implementation of DAQ & data handling – Parallel studies with test tanks in labs at UD

and UWRF– Simulation studies in parallel for calibration,

event reconstruction (Peter Niessen’s talk)

Uppsala, Oct. 9, 2004 Tom Gaisser 24

IceTop Collaboration

Meeting

Nominal layout of IceTop

Minimize deviations from nominal 125 m grid

Station configurations for 04/05

IceTop Station and Surface Junction Box Interface to IceCube System

24VDC

+/-48VDC

FreezeController

TemporarySmurf Cables2 +/-48VDC Cables 1 RS485 Data Cable

Surface Cablefrom Counting House

Surface to DOM CableFrom Hole

Surface Junction Box

IceTop Excavation

NOTES:1. Drawing is in approximate relative scale.2. Tanks are 10 meters between centers. 3. DOM cables are 17 meters long.4. RS485 Master source is controlled by plugging in the desired data cable.5. Tank power source is controlled by plugging in desired power cable.6. Power Converter contains +/-48VDC to 24VDC converter and EMI filter.

George AndersonSept 17, 2004File Rev F

PowerConverter(green box)

04/05 IceTop schedule

* Power required

** Water required

Dec 1 Dec 10 Dec 20Jan 6

Connect to TCH

Fill tanks

Jan 20 Feb 3

Backfill

Cover tanks

RunDOMs

Evenson 12/4 – 12/27

Gaisser 11/26-12/14

Tilav 1/12 – 2/1

Roth 11/26-12/16

Jamesway

SMURF TCH

Lundberg 12/17-1/13

Kelley 12/17-1/18

Uppsala, Oct. 9, 2004 Tom Gaisser 28

IceTop Collaboration

Meeting

SMURF = temporary temporary counting house to provide power,& monitoring of freeze control ~ 12/1 to 1/15 when TCH is ready

Some events

Uppsala, Oct. 9, 2004 Tom Gaisser 30

IceTop Collaboration

Meeting

time in 25 ns bins

calibration in Auger

even

ts

muon charge distribution

3 PMT avg traces

Uppsala, Oct. 9, 2004 Tom Gaisser 31

IceTop Collaboration

Meeting

Muon self-calibration procedure

• 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

Vertical (defined by-telescope)

In-tank coincidence (defined by 2 OMs) broadened peak + low energy e-m background

Data with test-tank setup at UD in water. (Large negative amplitudes on left.)

Uppsala, Oct. 9, 2004 Tom Gaisser 32

IceTop Collaboration

Meeting

Compress by ~10 for IceTop