CRT Requirements For ProtoDUNE Michael Mooney BNL ProtoDUNE CRT Meeting March 20 th , 2017
Introduction Introduction ♦ We will not have a UV laser system at the single- phase ProtoDUNE (unlike MicroBooNE, SBND) • Instead, plan is to have a cosmic ray tagging (CRT) system installed on the upstream/downstream ends of the detector w.r.t. beam direction • Possibly more CRT panels installed elsewhere (e.g. top of cryostat)? ♦ What should dictate CRT panel placement? • Ultimately, capability to obtain sufgicient rate and coverage of cosmics that can be utilized for calibrations ♦ If a science program is important to ProtoDUNE, essential to have these calibrations done • Useful for technical program as well – what is spatial variation of electron lifetime throughout detector? 2
Calibrations Calibrations ♦ Electronics response (e.g. gain, shaping-time) • Can be done with pulser data ♦ Wire response • Can be done in-situ or with test stand ♦ Space charge efgects • Must be done in-situ with cosmic/laser tracks ♦ Electron lifetime • Must be done in-situ with cosmic/laser tracks ♦ Recombination • Can be done in-situ, with test stand, previous exp. ♦ Difgusion • Can be done in-situ, with test stand, previous exp. 3
Calibrations Calibrations ♦ Electronics response (e.g. gain, shaping-time) • Can be done with pulser data ♦ Wire response • Can be done in-situ or with test stand ♦ Space charge efgects • Must be done in-situ with cosmic/laser tracks ♦ Electron lifetime • Must be done in-situ with cosmic/laser tracks ♦ Recombination • Can be done in-situ, with test stand, previous exp. ♦ Difgusion • Can be done in-situ, with test stand, previous exp. 4
Calibrations Calibrations ♦ Electronics response (e.g. gain, shaping-time) • Can be done with pulser data ♦ Wire response • Can be done in-situ or with test stand In order to reveal electron lifetime ♦ Space charge efgects efgects, must fjrst calibrate out SCE. • Must be done in-situ with cosmic/laser tracks Removing SCE can be done with strictly spatial information from hits (natural fjrst calibration). ♦ Electron lifetime • Must be done in-situ with cosmic/laser tracks How bad is SCE expected to be ♦ Recombination at ProtoDUNE? • Can be done in-situ, with test stand, previous exp. ♦ Difgusion • Can be done in-situ, with test stand, previous exp. 5
ProtoDUNE Geometry ProtoDUNE Geometry ♦ Nominal ProtoDUNE geometry: • Drift (X): 3.6 m • Height (Y): 5.9 m • Length (Z): 7.0 m ♦ Dimensions used for simulations slightly difgerent (to simplify calculations): • Drift (X): 3.6 m • Height (Y): 6.0 m • Length (Z): 7.2 m 6
Modifjed E Field (Central Z) Modifjed E Field (Central Z) 7
Modifjed E Field (TPC End) Modifjed E Field (TPC End) 8
Spatial Distortions (Central Z) Spatial Distortions (Central Z) 9
Spatial Distortions (TPC End) Spatial Distortions (TPC End) 10
SCE Calibration SCE Calibration 11
CRT Panel Arrangement CRT Panel Arrangement ♦ One possible arrangement of CRT panels: 8+8 on front, 8+8 on back (H+V) ♦ Will be useful for tagging both muon halo and cosmic muon tracks ♦ Totals 32 panels, but possibly install more elsewhere (e.g. on top)? 12
CRT Panel Arrangement CRT Panel Arrangement ♦ One possible arrangement of CRT panels: 8+8 on front, 8+8 on back (H+V) Again, CRT panel placement dictated ♦ Will be useful for by cosmic/halo rate/coverage requirement: tagging both muon halo and cosmic – Complete coverage of TPC volume muon tracks – High enough rate to do calibration ♦ Totals 32 panels, but possibly install more elsewhere (e.g. on top)? 13
CRT-tagged Sample CRT-tagged Sample Matt Worcester 14
Additional Sample Additional Sample MicroBooNE MC MicroBooNE Data ♦ Can also use anode-piercing and cathode-piercing tracks to do calibration (uses TPC, light information) Uses track topology to tag t 0 • • Noticeable gap in coverage in center of TPC 15
Summary Summary ♦ SCE spatial distortions at ProtoDUNE are quite severe! • 500 V/cm drift fjeld: ~4 cm longitudinal, ~20 cm transverse • 250 V/cm drift fjeld: ~20 cm longitudinal, ~60 cm transverse ♦ This, along with associated E fjeld distortions, can signifjcantly impact calorimetry and make downstream calibration difgicult (e.g. electron lifetime) ♦ Upstream/downstream CRT panels will help tag muons for calibration, both muon halo and cosmics • Helps fjll in gap in TPC centers seen in other tagged track samples • Additional panels on top would provide even more coverage in gaps 16
BACKUP SLIDES 17 17 17
Space Charge Efgect Space Charge Efgect ♦ Space charge : excess electric charge (slow- moving ions) distributed over region of space due to cosmic muons passing through the liquid argon • Modifjes E fjeld in TPC, thus track/shower reconstruction • Efgect scales with L 3 , E -1.7 Ion Charge Density Approximation! K. McDonald B. Yu No Drift! 18
Impact on Track Reco. Impact on Track Reco. ♦ Two separate efgects on reconstructed tracks : A • Reconstructed track shortens laterally (looks rotated) • B Reconstructed track bows toward cathode (greater efgect near center of detector) ♦ Can obtain straight track (or multiple-scattering track) by applying corrections derived from data- driven calibration Cathode A B Anode 19
Sample “Cosmic Event” Sample “Cosmic Event” MicroBooNE Nominal Drift Half Drift Field Field 500 V/cm 250 V/cm 20
Complications Complications ♦ Not accounting for non-uniform charge deposition rate in detector → signifjcant modifjcation? ♦ Flow of liquid argon → likely signifjcant efgect! • Previous fmow studies in 2D... difgerences in 3D? • Time dependencies? No Flow Flow w/o Turbulence Flow w/ Turbulence B. Yu 21
Liquid Argon Flow Liquid Argon Flow B. Yu 22
Smoking-gun for SCE Smoking-gun for SCE ♦ Can use cosmic muon tracks for calibration • Possibly sample smaller time scales more relevant for a particular neutrino-crossing time slice • Minimally: data-driven cross-check against laser system calibration ♦ Smoking-gun test : see lateral charge displacement at track ends of non-contained cosmic muons → space charge efgect! • No timing ofgset at transverse detector faces • Most obvious feature of space charge efgect Δy edge Drift Δy edge Anode 23
35-ton with LAr Flow with LAr Flow 35-ton Δx Δx central z slice With Without LAr Flow LAr Flow Q map from 24 E. Voirin
35-ton with LAr Flow 35-ton with LAr Flow (cont.) (cont.) Δy Δy Without With LAr Flow LAr Flow Q map from central z slice E. Voirin ~0 Δz Δz Without With LAr Flow LAr Flow 25
Simulation of SC Efgect Simulation of SC Efgect ♦ Can use SpaCE to produce displacement maps Forward transportation : {x, y, z} true → {x, y, z} sim • – Use to simulate efgect in MC – Uncertainties describe accuracy of simulation Backward transportation : {x, y, z} reco → {x, y, z} true • – Derive from calibration and use in data or MC to correct reconstruction bias – Uncertainties describe remainder systematic after bias- correction ♦ Two principal methods to encode displacement maps: • Matrix representation – more generic/fmexible • Parametric representation (for now, 5 th /7 th order polynomials) – fewer parameters – Uses matrix representation as input → use for LArSoft 26 implementation
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