LArTPC Testbeam: CAPTAIN and LArIAT Jason St. John, University of Cincinnati On behalf of the LArIAT Collaboration and for the CAPTAIN Collaboration NuFact 2015, Rio de Janeiro
Outline miniCAPTAIN (neutrons) & LArIAT (charged species) - Liquid Argon TPC Test Beams for Neutrino Physics - Physics goals - R&D goals - Experimental Setups - Incident Beams - Inside the cryostat - Beautiful data - Future plans 2
LArTPCs Test Beams for Neutrino Physics Liquid argon time projection ICARUS chambers (LArTPCs) capture neutrino interaction final products in MicroBooNE unprecedented detail Dedicated calibration effort needed DUNE SBND 3
MiniCAPTAIN Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos 4
MiniCAPTAIN The mini- CAPTAIN cryostat 1m Ø LArTPC in neutron beam at Weapons Neutron Research facility Physics goals: Ar* nuclear de-excitations Neutron scatters at known E n Neutron-induced π ± production 5
Los Alamos National Lab Los Alamos Neutron Science Center 6
Incident Beam Known neutron energy from Time of Flight - Beam on target starts clock - Cryogenic PMTs stop it Neutron beam energy spectrum will be closely matched to cosmic-induced neutron energy spectrum 7
Inside the cryostat The time projection chamber - MicroBooNE cold electronics - 3 planes @ 3 mm pitch - Drift field ~500 V/cm Wire/anode planes 1 m 32 cm Readout Cathode ASICs wires - 16 x 1” PMTS 8
LArIAT Liquid Argon In A Testbeam 9
LArIAT The ArgoNeuT/LArIAT “Table-top” (170L) LArTPC in a test beam TPC and cryostat at Fermilab Test Beam Facility - Repurposed ArgoNeuT detector - Physics goals: - π -Ar interactions 40 cm - e / γ shower ID - μ -Ar capture 90 cm - non-magnetic charge determination - kaon studies 47 cm - Geant4 validation - R&D goals: Optimize PID algorithm, calorimetry with charge & light, and 2D/3D event reconstruction 10
Fermilab Test Beam Facility Linac Booster Main Injector 11
Beamline Plan View Primary Target (Al) Primary 120 GeV p Tunable 8 - 64 GeV π ± Secondary Target (Cu) Tertiary Beamline & LArIAT TPC 12
Beamline Plan View Primary Target (Al) Primary 120 GeV p next slide Tunable 8 - 80 GeV π ± Secondary Target (Cu) Tertiary Beamline & LArIAT TPC 13
Tertiary Beamline Aerogel collimator Cu target counters Time of flight μ range scintillators stack Cryostat & TPC Secondary beam 8-64 GeV π ± Multi-wire proportional μ punch- Bending chambers through dipole magnets (MWPCs) paddles 14
Tertiary Beamline 15
Incident Particle Beam MWPCs + bending magnet - Charge-selected beam 200 - 1200 MeV/c - Single-particle momentum measurements Downstream MWPCs Upstream MWPCs Δθ Momentum windows in J. St. John excellent agreement with simulation 16
Incident Particle Beam MWPCs + bending magnet I.Nutini Full and Half momentum settings/magnet currents cover MicroBooNE neutrino event secondary momentum range 17
Incident Particle Beam Time of flight (TOF) for separation between π ’s/ μ ’s π / μ and protons ~2:1 ratio of π / µ to p J. Ho p J. Ho p K π/μ TOF vs reconstructed momentum 18
Incident Particle Beam Aerogel Cherenkov counters for further PID Possible π vs. μ discrimination using Fast E. Iwai combination of thresholds particles and pulse height Effective for TPC-contained π/µ range: 230-400 MeV/c Slow particles 19
Incident Particle Beam Muon range stack for discrimination of through- going muons/pions Effective for high-p π/µ range: 400+ MeV/c Some commissioning still π +/- ongoing μ +/- 20
Inside the cryostat The time projection chamber - Repurposed from ArgoNeuT Wire/anode - New wire planes, 240 wires each planes - shield - induction - collection - Drift field ~500 V/cm Cathode plane Pulse Shaping & 40 Amplifying cm 9 0 ASICs c m 47 cm 21
Inside the cryostat Light collection system - 2 PMTs + 3 SiPMs - VUV scintillation light wavelength- shifted at TPB-coated reflector foils lining field cage Photoelectron yield: ~40 p.e./MeV at zero E-field TPB reflector Field cage 22 wall
First data ▪ April 30, 2015 – TPC turned on, first cosmic-triggered track! LArIAT 23
First data …and first beam events soon after… LArIAT 24
Tired, Happy Scientists 25
Primer on beam events e m i t t f i r d drift time y U z U wire Incident Beam Direction e m drift time i t t f i r d y V LArIAT V wire z 26
Some event topologies seen by LArIAT π +/- single charge exchange γ p π +/- p γ γ p π +/- p γ LArIAT 27
Some event topologies seen by LArIAT Stopping/decaying π +/- π - absorption on Ar e +/- p π +/- π - μ +/- p e +/- p π - π +/- μ +/- p LArIAT LArIAT 28
Some event topologies seen by LArIAT e +/- -initiated shower Photon-initiated shower Distinguishable using dE/dx at start of shower LArIAT LArIAT 29
Some event topologies seen by LArIAT K +/- → π +/- π 0 γ γ K - e - π - µ - γ γ K - e - π - µ - LArIAT 30
Some event topologies seen by LArIAT K +/- → π +/- π 0 γ γ K - Monte Carlo e - π - µ - γ γ K - e - π - µ - LArIAT 31
Summary of Run I Beam data taking ran about 2 months Low-E Beam-taking source running 32
A few ongoing analyses… 33
Eye scan of a small fraction of the data Topology breakdown among the unambiguous, single-track events A rich physics program will emerge from analyses! N. Birrer K. Nelson S. O’Neil 34
Reconstruction status MWPC1 Rapid progress in MWPC2 reconstructing both Wire chamber beamline & TPC TPC tracks volume ionization tracks MWPC3 M. Smylie MWPC4 A. Olivier Pion Cosmic μ scatter R. Acciarri T. Yang I. Nutini 35
N 2 levels with scintillation light N 2 content in LAr suppresses scintillation light Nitrogen contamination Comparison with model from WArP From fits to scintillation Slow component decay time (/ns) light extract “late” light time component and determine N 2 concentration Results agree with gas analyzers P. Kryczynski A. Szelc Nitrogen concentration (/ppm) 36
Electron lifetime / O 2 levels with cosmic μ ’s Dedicated paddles μ for cosmic- μ triggers Fit to charge vs. drift time for measurement of electron lifetime Able to calculate O 2 concentration below sensitivity of our gas analyzers Current results show O 2 < 1ppb, agreement with gas analyzers R. Acciarri 37
Pion interactions I – elastic scattering absorption charge pion inelastic scatter on Ar exchange production Pion-Argon elastic scattering Look for kinks in incoming pion-tagged tracks LArIAT I. Nutini 38
Pion interactions II – absorption Pion absorption - Incident tagged π , no π ’s in final state - Often accompanied by protons/neutrons LArIAT LArIAT 39
Pion single charge exchange π + + n π 0 + R. Linehan p γ γ Reconstructed “clusters” Active effort to ID and reconstruct π 0 mass peak from m γγ - - Cross section MC studies to understand containment of these events in TPC J. Ho J. Ho 40
Michel electrons Ideal e +/- spectrum for decaying free μ LAr scintillation-based trigger to record stopping/decaying cosmic μ ’ LArIAT s Decay time of LArIAT Michel candidates (~10 hrs data) Initial reconstruction focused on light signals only Preliminary - Track/shower algorithms to follow Eventual use as energy calibration source and measurement of μ - nuclear capture rate ns 41
Summary LArTPC test beams are getting underway! MiniCAPTAIN has just seen its calibration laser track - Neutron beam running will begin soon LArIAT’s run 1 was a success – lots of new data to analyze - Offline event reconstruction actively evolving day-by-day - Several analyses underway with more to come - Actively preparing for Run II this Autumn Detailed calibration, cross sections, etc. on the horizon! 42
Thank you! 43
Backup 44
Beam commissioning Installation of beamline detectors and TPC-less running to test them (and characterize the beam) Completed summer 2014 45
Cryogenic Ultra-Pure LAr 46
Powerful, flexible trigger system 47
Incident Beam Time of Flight → E n - Beam on target starts clock - Cryogenic PMTs stop it Time structure of n beam: - 625 µs macropulses of sub-ns micropulses @ 1.8 µs - 40 Hz macropulse rate Neutron beam closely matched to cosmic-induced neutron spectrum 48
Time Structure of the Beam abort gap 1.8 ns buckets 18.8 ns peak-to- peak 84 buckets per bunch 7 bunches per orbit 4.2 seconds of beam per spill = 380k orbits * 18.8 ns * 7 * 84 1 spill every 60.8 seconds 49
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