Calibrating detectors for dark matter search at ALTO D. Franco Dark Matter Particles A number of indirect observations: collider production - Galaxy clusters - Galactic rotation curves � q D irect detection - Weak lensing - Strong lensing - Hot gas in clusters Q - Bullet Cluster - Supernovae - CMB - … � q indirect detection Dark Matter particle properties: - Cold - Gravitational force WIMP - No electric charge or color - No strong and em interactions - Stable or very long lived 2 Davide Franco – APC Paris Backgrounds and Detector Requirements Cosmic rays and cosmogenic isotopes Natural (238U,232Th,235U,222Rn,…) and anthropogenic (85Kr,137Cs,…) radioactivity Neutrinos (solar, atmospheric, diffuse supernovae) Neutrons WIMP detector requirement: - Large mass - Low energy threshold Detectable Signal - Ultra-low background E < 100 keV R - Signal/background discrimination Electron Recoil Either background free or β, γ WIMP perfectly constrained background Or clear signature (annual modulation, directionality) Davide Franco – APC Paris 3 Direct Detection Techniques A few meV Phonons for phonon production Al2O3: CRESST Ge,Si: CDMS CaWO4, Ge: EDELWEISS Al2O3: CRESST C,F,I,Br: 10-100 eV for PICASSO,COUPP light A few eV for Ge: LXe: XMASS production in Texono,CoGeNT ion-electron LAr: LAr/LNe: Deap/Clean noble liquids CS ,CF , 3He: production 2 4 DarkSide and in DRIFT,DMTPC, ArDM NaI: Dama/Libra scintillators MIMAC NaI: Anais 6 LXe: Ar+C2H : Newage CsI: KIMS Xenon PandaX LUX Charge Light Davide Franco – APC Paris 4 Search Status Bolometers Anomalies Noble liquids + Solid State already constrained + Bubble chambers ������ �������� -�� -� �� �� �� ����� ] ����������� ] � �� �� [ �� [ ��-�� ��-� ����������� �� �� -�� -� ��� ��������� �� �� �� -�� �������� ��� ����-��������� ��-�� �������� ��-� -�� -�� ������� ����� ������� ������� ������� ������� �� - - -�� -�� �� �� ���� ���� ���� ����� ������� ������� �� ����� ����� ���������� �� ������� ��� �������� ��������� ������������ ���������� ������� ��������� �� ��������� ��-�� � �� ��� ���� ���� ���� [���/��] Davide Franco – APC Paris 5 Sensitivity Enhancement Strategies: 1) Increasing target mass 2) Lowering the analysis/trigger threshold 3) Constraining the response Ionization Signal in a Liquid Argon Target at 1 GeV WIMP Mass Ideal Spectrum Nuclear Recoil Quenching Ionization Channel Electric Field Effects Intrinsic Fluctuations Detector Resolution Davide Franco – APC Paris 6 Noble Liquid TPCs Energy deposition! Heat! Excitation! Ionization! Ar*! +! Ar Electrons! * Ar 2! + Ar 2! S2! Singlet ! Triplet! ** Ar ! S1 ! Recombination! In Argon: powerful pulse shape discrimination in primary scintillation channel 7 Davide Franco – APC Paris Calibration Methods Natural internal source External neutron source (39Ar, 127Xe) (AmBe, AmC) Uniformly distributed Direct measurement in Limited number of sources nuclear recoil mode Non-monochromatic Injected gaseous source (83mKr) Direct measurement D-D gun in the veto Limited number of sources Monochromatic neutrons Electron Recoil only Recoil energy reconstruction External gamma source (241Am, 133Ba) Known energy Events close to the borders Davide Franco – APC Paris 8 Cross Calibrations - Response of noble liquids depends on the purity level only - Bolometers and solid state detectors can be “moved” for lab tests γ beam Davide Franco – APC Paris 9 ReD @ LNS (Catania) Recoil Directionality Studies in Two-Phase Liquid Argon TPC Detectors Beam: TPC: - Continuous - equipped with SiPM - p(7Li,7Be)n - High segmentation - Tagging of 7Be - Large PDE (~40%) From M. Rescigno at IDM 2016 Davide Franco – APC Paris TUNL Beam: - Pulsed - 7Li(p,n)7Be From P. S. Barbeau @ US Cosmic Visions 2017 Davide Franco – APC Paris TUNL A nice philosophy! From P. S. Barbeau @ US Cosmic Visions 2017 Davide Franco – APC Paris TUNL From P. S. Barbeau @ US Cosmic Visions 2017 Davide Franco – APC Paris @ LICORNE http://aris.in2p3.fr arXiv:1801.06653 Davide Franco – APC Paris 14 LICORNE: inverse 7Li(p,n)7Be LICORNE is ideal because: - Pulsed (1.5 ns width) Data RMS ~0.085 MeV - Monochromatic MC Mean ~1.450 MeV - Collimated - Emits also correlated 478 keV gammas But - Close to the reaction threshold (~13.096 MeV) - Need specific calibration at each run +0.02 Lithium energy : 13.13 -0.01 MeV Davide Franco – APC Paris 15 ARIS @ LICORNE Small-scale: ideal for single scatters 3 Scattering MC Determined Angle [deg] Mean NR Energy [keV] 1 A0 25.5 7.14 1.9 A1 35.8 13.72 1.8 A2 41.2 17.78 1.7 10−1 A3 45.7 21.69 1.6 A4 64.2 40.45 1.5 A5 85.5 65.37 Neutron energy [MeV] A6 113.2 98.14 1.4 2 A7 133.1 117.78 1.3 10− 1.2 TABLE I. Neutron scattering angles and NR mean ener- gies determined by a MC simulation taking into account 1.1 neutron energy spread, neutron cone width, and de- 0 5 10 15 20 25 Neutron angle [deg] - ~0.5 kg of LAr tector widths. Q: I removed the uncertainty on the - PTFE reflector with TPB coatedMC surface energies. FIG. 2. The best fit beam profile of ELi = - 7 Hamamatsu 1’’ PMTs on top, one 3’’ PMT on bottom +0.02 - Ability to create a gas pocket for dual-phase running 13.13 0.01 MeV after a 2.06 µm Ta foil is shown. 160 stability of the PMTs during the data taking. The − - Anode/Cathode created with ITO plated fused-silica windows 161 gains of the PMTs are found to have good stability - Grid 1 cm below the anode provides bias for electron extraction 201 the TPC and A0-7, and time-of-flight (TOF) param- 162 during the period of data collection presented in this 202 eters. The final observables are used for the data 163 work. 203 selection and analyses reported in the subsequent 164 The TPC is mounted with its center 1 m away204 sections of this work. Davide Franco – APC Paris 16 165 from the LICORNE target. Eight liquid scintillator 166 detectors, labeled A0-7, are mounted at various radii 167 and angles around the TPC in order to scan the205 B. LICORNE beam 168 range of neutron scattering angles shown in table I. 169 A0-7 utilize a 20 cm diameter and 5 cm high cylinder 206 The LICORNE neutron source generates a colli- 170 of NE213 liquid scintillator, providing good pulse 207 mated neutron beam by exploiting the inverse kine- 171 shape discrimination between neutrons and gammas 1 7 7 208 matics of the H( Li,n) Be reaction. This source 172 for background reduction [? ]. The positions of A0-7 7 209 consists on a hydrogen gas cell coupled to a Li beam 173 were precisely determined via surveying before the 210 at 14.63 0.01 MeV. The gas cell and the beam pipe 174 data taking. ± 211 are separated by a thin tantalum foil. The beam pro- 175 The signal from the PMTs of the TPC and A0-7212 file, which describes the energy-angle distribution of 7 176 are digitized by two CAEN V1720 boards [? ] at213 the neutrons (En, ✓n), is determined by the Li beam 177 a 250 MHz frequency, with the beam pulse time in-214 energy and target geometry. Before the nuclear re- 7 178 formation digitized by a CAEN V1731 board at a215 action, Li nuclei lose a part of their energy when 179 250 MHz frequency. The beam pulse is triggered at216 passing through the Ta foil and the gas cell. In or- 180 a rate of 2.5 MHz, with a neutron flux of <20 kHz217 der to estimate the beam profile for a given Ta foil 7 181 used during the beam run. A triple coincidence be-218 thickness and a given Li beam energy, a Geant4 182 tween the beam pulse, two-PMT majority trigger219 based simulation of the LICORNE sources has been 183 of the TPC, and a trigger from one of the detec-220 developed by Q. Liquiang et al. at IPNO [add ref]. 184 tors A0-7 provides angle-tagged events. The board221 For the simulation, all of the parameters are mea- 185 timestamps are synchronized by an external clock to222 surable except the thickness of the Ta foil due 186 allow time of flight measurements. 223 to the constraints set by the pressure di↵erential 187 For each trigger, the PMT waveforms, A0-7 wave-224 between the cell (at 1.1 bar) and the beam pipe 6 188 forms, and the signal from the beam pulse are225 ( (10− ) mbar). In order to constrain the beam pro- O 189 recorded. These signals are analyzed by a recon-226 file, a dedicated measurement is performed by plac- 190 struction software based on the art framework [?227 ing one of the neutron detectors 3 m from the target 191 ] to extract observables from the recorded wave-228 at angles varying between 0 and 15◦ and measur- 192 forms. First, fluctuations and drift of the baseline229 ing the relative beam intensity as a function of the 193 are tracked and subtracted from the raw signal wave-230 angle. 194 forms. Next, waveforms from each PMT in the TPC231 A library of simulated beam profiles and subse- 195 are corrected for their SER and summed together.232 quent neutron intensities for each neutron detector 196 A pulse finder algorithm is applied to each summed233 position are generated by varying the Ta foil thick- 197 waveform to identify the magnitude and start time234 ness in the simulation. The best fit profile from a 2 198 of TPC and A0-7 pulses. Finally, the reconstructed235 χ test between the data and simulation shows the 199 waveform and pulse information is used to extract236 Ta foil thickness to be 2.06 0.08 µm, correspond- +0.02 ± 7 200 S1, pulse shape discrimination parameters for both237 ing to a 13.13 0.01 MeV mean Li energy after the − ARIS Performance 200 1 f90 2 102 0.9 10 (1) (1) 0.8 (3) 150 NDtof [ns] 0.7 (3) 0.6 10 100 10 0.5 0.4 50 0.3 1 1 0.2 (2) (4) 0 0.1 (2) 0 −10 0 10 20 30 40 50 60 70 80 −10 0 10 20 30 40 50 60 70 80 TPCtof [ns] TPCtof [ns] 1 102 ND PSD D1 0.8 0.6 10 D3 0.4 1 D2 0.2 D4