Post on 19-Jan-2016
transcript
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