How to measure dark matter with XENON1T SPS Annual Meeting 2014 Lukas Bütikofer AEC University of Bern 30.6.2014 lukas.buetikofer@lhep.unibe.ch
Indirect evidence of dark matter Dark matter candidates: WIMPs ( Weakly Interacting Massive Particles) Axions ... Planck Galaxy rotation curves Lensing Cluster lensing + x-ray 1 Lukas Bütikofer “How to measure dark matter with XENON1T”
Direct WIMP detection ● featureless falling exponential A 2 enhancement ● ● low threshold required WIMP detectable nuclear recoil E~O(10 keV) Event Rate: => rare event search Particle Physics => go underground Detector Local dark matter density WIMP mass 2 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON at LNGS 1.4 km of rock (3600 mwe) => muon flux reduction by a LNGS factor of 10 6 L’Aquila Teramo XENON100: operating detector total mass 161 kg, target mass 62 kg reached limit of 2*10 -45 cm 2 at 55 GeV/c2 (PRL 109, 181301 2012) Astropart. Phys. 35, 573 (2012) 3 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON detector principle Example XENON100 Waveform Ionization signal (S2) Scintillation signal (S1) two signals S1, S2 3D position reconstruction x-y from hit pattern z from drift time => fiducialization => double scatter rejection => signal/background discrimination 4 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON1T ● total Xenon ~3.3 t (~2 t active) ● fiducial mass ~1 t ● total of 248 PMTs ● Background goal: <1 event in 2 years (NR plus ER) ● International collaboration, construction at Gran Sasso ongoing 5 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON1T is under construction Service Building Water Tank Support Structure 6 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON1T is under construction xenon storage 7 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON1T is under construction cryostat 8 Lukas Bütikofer “How to measure dark matter with XENON1T”
XENON1T is under construction cable pipe 9 Lukas Bütikofer “How to measure dark matter with XENON1T”
Detector calibration Background spectrum from XENON100 useful energy range out of region of for DM search interest Simulation of XENON1T calibration High rates are required for detector external Y R source calibration A N I M I L E R P 10 Lukas Bütikofer “How to measure dark matter with XENON1T”
DAQ requirements ● Digitize and store complete waveforms ● Low/”no” threshold ● High rates, up to 1 kHz (300 MB/s) ● High energy veto in calibration mode PRELIMINARY 11 Lukas Bütikofer “How to measure dark matter with XENON1T”
DAQ system everything is read to Buffer peak finding and triggering is done on software level Data Read Rate CAEN v1724 digitizers rate MB/s ● 248 synchronised, independent channels ● self trigger of each channel below ~0.3 photoelectron ● deadtime-less readout ● internal delay allows vetoing HE events time directly on the board ● test setup with 40 channels fully operational in Bern 12 Lukas Bütikofer “How to measure dark matter with XENON1T”
DAQ system sum veto High Energy veto custom programmed FPGA firmware allows for: ● online integration of sum waveform ● blocking of HE events before read out ● flexible veto conditions (energy, length…) ● position dependent veto is possible ● test setup with 40 channels fully operational in Bern 13 Lukas Bütikofer “How to measure dark matter with XENON1T”
HE veto ● skutek DDC-10 VME board: ○ 10 channels 14 bit digitizer ○ 4 NIM/TTL In ○ 4 NIM/TTL Out ○ embedded Linux ○ custom programmable FPGA ● custom FPGA firmware developed at Bern: ○ live integration of sum waveform ○ veto decision on pulse integral, width and risetime ○ flexible veto length (dependent on integral) ○ position dependent veto is possible ○ fast, online, passive input input output output 14 Lukas Bütikofer “How to measure dark matter with XENON1T”
where to go with XENON1T ● data taking starting 2015 sensitivity 2*10 -47 cm 2 1t*2 years ● ● XENONnT upgrade: 7t xenon in total Everything prepared for XENONnT 15 Lukas Bütikofer “How to measure dark matter with XENON1T”
Recommend
More recommend
