1. Performance of the AMANDA-II Detector
R.Wischnewski for the AMANDA Collaboration; DESY-Zeuthen, Germany
AMANDA-II Detector
 Largest High Energy Neutrino-Detector ever
built:An open Under-Ice Cerenkov Detector for
high energy muons and showers.
 19 vertical strings with 677 Optical Modules (OM):
8 inch PMTs with analog pulse transmission to
surface.
 Construction started in fall 1995, full detector
commssioned in early 2000.
 Different technologies applied:
 strings 1-10: analog electrical pulse transmission
 strings 11-19: analog fiber pulse transmission
 1 test string with Digital OM technology
(IceCube prototype)
AMANDA-B10
The various analog OMs used in AMANDA-II: electrical and fiber readout modules, and the digitally controlled module (from left to right). For Digital OM see H.E.2.05
Results obtained with the10 string detector AMANDA-B10 (1997 data)
 Isolation of 325 atmospheric vμ achieved - proof of performance (Nature,2001) - HE2.03
 Limits on flux of HE diffuse vμ/ve-flux (AGN) - HE2.03
 Limits on v-flux from point sources and GRB and UHE-v - HE232/236
 Limit on WIMPs, on relativistic magnetic Monopoles and galactic Supernova v‘s - HE231
AMANDA-II
Signal Expectation
First Analysis
Astrophysical sources: AGN, GRB, SN-shells, topological defects,...
with spectra much harder than v‘s generated in the atmosphere
Assume a diffuse AGN E-2 spectrum: E-2 GeV sr-1 s-1 cm-2
 Trigger level acceptance of vμ and v e Charged Current (CC)
and Neutral Current (NC) interactions:
Trigger: majority trigger (>23 OMs in 2.5 μs) and local cluster trigger
external: EAS-array SPASE
Data sample: 1.3 TB raw data in ca. 250 run days in 2000
MC-data comparison at trigger and higher v-cut levels
 number of hit PMTs (nOM), angular-distributions, pass.-rates fit well
 absolute rates & vertical hit structure under study (ice, noise)
Data-analysis for AMANDA-II/2000 has started.
Preliminary v -cuts developed.
Triggered events / year
Atmospheric AGN
vμ (CC) (NC) (CC)
ve (CC) (NC) (CC)
Atm
AGN vμ
Number of hit optical modules per event, nOM(dots- exper., histogram -MC). ve
Neutrino energy spectrum for events, triggering AMANDA-II: CC vμ-events (thick lines) and CC ve-events (thin lines) for atmospheric neutrinos (full lines) and AGN like neutrinos (dashed-dotted lines).
Zenith angle distribution for atmospherci nmu MC events in AMANDA-II (full line), compared to AMANDA-B10 detector (dashed). Preliminary cuts, normalized for vertical bin.
An AMANDA-II v-candidate close to the horizon,
May 2000.
Conclusions
 AMANDA-II is in stable operation and delivers high quality
muon and neutrino data.
 Neutrino-event selection is much improved over AMANDA-B10
by better geometry and better OM timing.
 Neutrino event-rates will be at least 3 times larger compared to B10.
 Angular acceptance is much improved for horizontal tracks,
opening full lower hemisphere for HE-neutrino astronomy.
 DAQ-Upgrade planned for 2001/02 for improved HE/UHE sensitivity.
Reconstructed zenith angle cos(Θreco) (left) and azimuth angle Φreco (right, in degress) at trtigger level