Particle detectors: from underground to the space Isabel Lopes Laboratório de Instrumentação e Física Experimental de Partículas (LIP) Ciência 2017, July 3-5, Centro dos Congressos, Lisboa, portugal

Particle Detectors @LIP Particle/Radiation detectors are devices sensitive to the passage of particles and able to measure some of their characteristics, e.g. Energy Interaction position Interaction time Momentum Velocity LIP has a high level of expertise in radiation detection technologies, particularly in liquid xenon and gaseous detectors, including: Research on the fundamental processes R&D of detectors, associated electronics, control and DAQ systems Design and construction of detectors for a large variety of applications

Resistive Plate Chambers (RPCs) RPC principle: Single gap configuration Advantages: Very fast  very good time resolution (~50 ps) High granularity  very good position resolution (down to <0.1 mm) Very high efficiency (efficiency of ~ 95% is possible) Very robust and versatile Resistant to aging and radiation damage Low price Multigap configuration Drawbacks: Only for moderate count rates (up to ~1kHz/cm2) No energy resolution

RPCs@LIP: HADES detector HADES (experiment at GSI, Germany)  study cold nuclear matter at high densities created by ion collisions. LIP designed and constructed a high granularity, high-resolution Time of Flight (TOF) detector, based on timing RPCs. t0 t1 L Particle identification with TOF: if p is known Time resolution degradation (ps) Hits/sector/event [2014 JINST 9 C11015] Main challeges: t < 100ps (multihit) and  > 90% across ~ 8 m2 Results <t> = 81 ps <> = 97% Excellent multihit capability without time resolution deterioration due to innovative concept adopted: individually shielded RPC

RPCs@LIP: HADES detector rows 1122 cells total HADES cells 0.27 mm  4 gaps Aluminium and glass 2mm electrodes Gas: freon (C2H2F4)

RPCs@LIP: TOFtrackers TOFTracker: simultaneous track reconstruction and time information along the track 31 strips 16 groups TL1 TL16 TR1 TR16 Electronics box Size: ~1550 x 1250 mm2 Longitudinal coarse position = Xraw 4 x 0.3 mm gas gaps assembled in multi-gap configuration QYL Glass Gas gap QYR C2H2F4 in open gas flow. Fine transversal position = Y A tracking system capable of simultaneously measurement of accurate coordinates and time Signals are readout in both anode and cathode. ANODE. 2.3 mm (2.5 mm pitch) longitudinal strips. Time is readout at both ends in 16 groups of 31 strips => Longitudinal coarse position, Xraw => Time, T Xraw = TL – TR T = (TL + TR ) /2 Charge is readout in each group of 31 strips (charge division). => Fine transversal position. Y = (QYL - QYR) / (QYL + QYR) + Group position

RPCs@LIP: cosmic ray detector for AUGER Goal: TOFTracker for directly measurement of the muon content of the showers Main specific requirements: Standalone operation Outdoors operation -> resilience to humidity and other environmental effects Low maintenance -> very low gas flow Little aging Cerenkov tank PMT µ e Results: 6 such detectors at Argentinian pampas working continuously and successfully since two years (gas flow: ~1kg/year) RPC TOFtracker (1.25 x 1.55 m2)

RPCs@LIP: scatter muon tomography HIDRONAV project: RPC 4-layer TOFtracker for container inspection Position-sensitive detectors Scatterer Multiple Coulomb scatter (low angles) Signal=trajectory error ~ amount of matter traversed RPC planes

RPCs@LIP: Positron Emission Tomography Detection of two 511 keV g-rays in coincidence Time resolution for 511 keV photons: 300 ps FWHM for the photon pair Use the electrode plates as a g converter e- e+ e - .......... Glass Gas Full head Transaxial X Z Depth of interaction 3D measurement of the photon interaction point: 0.4 mm (FWHM) 8x8 cm2 Efficiency ~5% Full-body human RPC TOF-PET 900 mm 5 gaps 0.35 mm 6 x 0.38mm glass ~5 mm thick 2000 mm PET-animal scanner

RPCs@LIP: position sensitive thermal neutron detector Development of 10B4C coated RPCs for sub-millimeter resolution thermal neutron detectors LIP is member of SINE 2020 EU-Project Cd Mask 10B4C coated RPCs Detector Designed and Assembled @ LIP Detector Tests at TREFF neutron beam- line in TUM-FRM II 2D Spatial Resolution better than 236 μm FWHM for both X and Y

Optimization of GSPCs Gaseous Proportional Scintillation Counter (GSPC) (xenon @10atm) with internal photocathode Detector characteristics Appropriate for hard X-ray and gamma-ray detection (eff >25% for 662 keV g-rays) Very good energy resolution (~2% for 662 keV g-rays) Large size Competitive with solid state devices for large areas A – Top teflon support B – Bottom Teflon support C – Anode D – Shielding grid E - Collecting grid F - CsI photocathode G - alpha particle window Applications Homeland security (Radiation Portal Monitors) Instrumentation for boreholes in geological prospection Prototype developed (National patent n. 104417, 15 july 2013)

Liquid xenon detectors @LIP Worldwide acknowledged work and expertise on liquid xenon detectors, including R&D of liquid xenon detectors (e.g. nuclear medical imaging detectors) Physics studies on several aspects of this type of detectors Participate in the construction, commissioning and operations of large liquid xenon detectors for dark matter search Presently: Participation in LUX-ZEPLIN, which is a dark matter search experiment that uses a 10 ton liquid xenon detector (in construction stage). We are responsible for: Optical studies of materials immersed in liquid xenon Control system Vertex reconstruction Liquid xenon system @LIP, Coimbra besides many activities on data analysis

Detectors@LIP Excellency in Instruments Physics Algorithms New ideas 33 members 9 academic staff 6 LIP or FCT researchers 3 Post Docs 4 PhD students 9 technicians 2 others Excellency in Instruments Physics Algorithms New ideas Worldwide recognised expertise in the field  participation in many international large projects

Spares

RPCs@LIP: transmission muon tomography TOMUVOL project: Three layers completely equipped

RPCs

Comparison with the standard PET technology Disadvantages Certainly a much smaller efficiency: 20 to 50% as compared to 70 to 80%. No energy resolution, but there is an equivalent energy sensitivity... more later. Detector scatter (vs. “misidentified fraction” in crystal blocks) Advantages Increasing system sensitivity Inexpensive  large areas possible  large solid angle coverage Excelent timing  TOF-PET possible+optimum randoms rejection Increasing position accuracy Gaseous detectors routinely deliver 0.1 mm resolution Full 3D localization possible  no gross parallax error The very small gap minimizes intrinsic errors Other Simultaneous full body imaging (continuous uptake signal) Compatible with magnetic field  PET-MRI can be considered Possible specialized PET applications Whole-body Human PET 1 mm Small Animal PET Simulation: 0.51mm FWHM

Conclusions: LIP is a worldwide renown laboratory for its excellency in gaseous and liquid xenon detectors LIP participate in many medium and large international projects that involve the design, construction and maintenance of detectors of these types od detectors. Gaseous and liquid xenon detectors are widely used for a rich variety of applications