LArIAT Fermilab PAC Meeting November 11, 2016 Jen Raaf PAC Charge - PowerPoint PPT Presentation

LArIAT Fermilab PAC Meeting November 11, 2016 Jen Raaf

PAC Charge Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 2

Motivation: Needs of Neutrino Experiments Typical neutrino event Outgoing lepton: Flavor: CC vs. NC, µ + vs. µ - , e vs. γ Incoming neutrino: Energy: measure Flavor unknown Energy unknown Mesons: Final State Interactions Energy? Identity? Target nucleus: Outgoing nucleons: Nucleus remains intact for low Q 2 Visible? N-N correlations Energy? Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 3

LArIAT: Study Final State Particles ¤ Visible energy calibration ¤ Calorimetric response and resolution ¤ Particle identification ¤ Event reconstruction ¤ Hadron-argon scattering cross sections LArTPCs enable us to study these topics in unprecedented detail. Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 4

Motivation & Method Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 5

Test Beam Facility Primary beam Protons: 120 GeV Secondary beams available at FTBF Pion Mode: ~8-80 GeV beam Low Energy Pion Mode: 1-32 GeV beam ¤ a Muon Mode: Same energy range as above Tertiary beam @ MCenter Tunable: ~200 MeV – 1.5 GeV Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 6

Experiment Overview Multi-wire 2 ndary Cu target Cosmic Tagger proportional beam chambers Muon (8-80 GeV) (MWPCs) Halo veto Range Secondary beam Stack TPC Dipole Magnets Aerogel Cerenkov Collimators Muon Counters Punchthrough Time of Flight Veto (TOF) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 7

MCenter Tertiary Beam ¤ a 2 ndary beam (8-80 GeV) NB: Beam direction reversed from previous slide Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 8

LArIAT TPC ¤ The time projection chamber ¤ Repurposed from ArgoNeuT Wire/anode ¤ New wireplanes planes ¤ 1 shield plane: 225 vertical wires ¤ 2 readout planes: 240 wires each, +/-60 o , 4mm pitch ¤ Drift field ~500 V/cm Cathode plane Readout ASICs 40 cm 47 cm Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 9

LArIAT Goals Program for comprehensive characterization of LArTPC performance in the range of energies relevant to upcoming neutrino experiments. ¤ Physics goals ¤ π -Ar interaction cross sections ¤ Kaon interaction cross sections ¤ Geant4 validation ¤ Develop criteria for determining particle charge based on topology (decay vs. capture), without magnetic field ¤ Electron/photon shower ID ¤ R&D goals ¤ Ionization and light production properties Establish relationship between energy ¤ deposited to charge and light collected, for stopping tracks of known energy ¤ Optimization of particle ID methods ¤ 2D & 3D event reconstruction Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 10

Run-I and Run-II (Completed) ¤ LArIAT Run-I (Apr. 30 – Jul. 4, 2015) ¤ 9 weeks beam data (~3 weeks LE + ~5 weeks HE tune) ¤ 28k negative polarity spills + 31k positive polarity spills ¤ ~10-20 events/spill including cosmics & other non-beam triggers ¤ Mix of π / 𝜈 /K/p/e in beam triggers ¤ Collected ~5000 clean π – (conservatively) & ~100 kaons ¤ LArIAT Run-II (Feb. 19 – Jul. 25, 2016) ¤ 24 weeks beam data ¤ 73k negative polarity spills + 57k positive polarity spills ¤ ~80 events/spill including cosmics & other non-beam triggers ¤ Increased Michel trigger rate (improvements to DAQ) ¤ Beam tune chosen to increase kaon fraction ¤ Estimate ~1000 K + collected in this run + many π , p, etc. Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 11

Run-II Proton Usage Efficiency Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 12

Run-I & -II Analysis Highlights ¤ In-situ impurity measurements ¤ O 2 -equivalent concentration via cosmic rays ¤ N 2 concentration via slow component of light ¤ Light-based triggering/PID for Michel electrons ¤ Pion-Ar total cross section measurement ¤ Publication currently in preparation ¤ Exclusive interaction channel cross section measurements in progress ¤ Kaon ID & Kaon-Ar cross section ¤ In progress Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 13

Highlight: Oxygen Contamination ¤ Electronegative contaminants in the liquid argon (e.g., O 2 and H 2 O) quench the charge produced by interacting particles Cosmic tagger paddle Amount of charge per unit length (dQ/dx) collected at wire planes depends on distance it drifted Cosmic tagger paddle Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 14

Run-II Lifetime via Crossing Muons O 2 -equivalent concentration 0.32 ppb Changes on the TPC’s Filter voltages Regeneration 0.65 ppb Our LArSoft module for measuring electron lifetime (O 2 -equivalent concentration) using crossing muons can be easily adapted for use by other LArTPCs. Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 15

LArIAT Light Collection System 3 1 2 4 TPB-coated reflector foils on field cage walls Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 16

Highlight: Nitrogen Contamination Average signal [mV] τ slow = 1180 ns (N 2 < 0.1ppm) ¤ N 2 in LAr suppresses scintillation light P. Kryczynski ¤ From fits to scintillation, can extract “slow” light Sample (ns) time component and determine N 2 concentration Theoretical model ¤ Results agree with R. Acciarri et al. 2010 JINST 5 P0600 3 LArIAT Data trend from model LArIAT Preliminary Nitrogen contamination from gas analyzers (ppm) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 17

Highlight: Michel electron trigger (at rest) à e +/- + ν μ + ν e μ +/- μ +/- e +/- ¤ Energy calibration ¤ PID of stopping μ +/- μ +/- e +/- ¤ Training ground for shower reco, dE/dx, … Real-time triggering TPB-coated ETL PMT under a on Michel e’s from UV lamp (prior to “Run 2b”) stopping cosmic μ ’s using light signals Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 18

Highlight: µ - capture lifetime in Ar Dataset: ~ 12 days LIDINE 2015 Proceedings, JINST 11 C01037 650 ± 52 ns (from fit result, 918 ± 109 ns preliminary) ¤ Fit results agree with recent measurement 1 (616.9 ± 6.7 ns) ¤ Translates to a capture lifetime of 918 ± 109 ns, in agreement with theory prediction 2 (851 ns) 1 (Klinskih et al., 2008) 2 (Suzuki & Measday, 1987) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 19

Highlight: Michel e PE spectrum MC prediction ¤ Michel-candidate signals integrated to get photoelectron (PE) spectrum ¤ Data agree reasonably μ endpoint within 15cm of TPC center well with preliminary MC ¤ Gives confidence in MC-predicted light yield: 2.4 pe/MeV for 2” ETL PMT (Run-I) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 20

Highlight: “Sliced-TPC” Cross Section Measurement ¤ TPC wire spacing allows us to divide the (90 cm) thick LAr volume into a sequence of (~200) adjacent thin slices (~4.5 mm) orthogonal to the beam direction of the incident pion ¤ Incident pion’s kinetic energy is known at each slice ¤ Entering pion’s KE (E initial ) is known from tertiary beam instrumentation ¤ At each successive TPC slice, energy incident on that slice is determined by subtraction of calorimetric energy (dE/ds) released by pion in previous slices k − 1 incident = E initial − ∑ E k dE s s = 0 Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 21

Sliced-TPC Method If NO interaction in the slice, fill only N incid histo If YES, fill both hisograms ¤ Sample each pion multiple times along its trajectory through the TPC ¤ Each time it crosses a slice, fill 2 histograms ( N incid & N interact ) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 22

Sliced-TPC Method If NO interaction in the slice, fill only N incid histo ¤ s Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 23

Sliced-TPC Method YES!! Interaction in the slice! ¤ s Fill both hisograms Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 24

Sliced-TPC Method ¤ Repeat the process for the entire collected sample of pions Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 25

Cross Section ¤ Take the bin-to-bin ratio and calculate the cross section σ tot ( E kin ) = 1 n δ z Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 26

Highlight: “Sliced-TPC” Pion Cross Section ¤ Systematics considered: Presented at Fermilab ¤ dE/dx calibration: 5% Wine & Cheese Seminar, ¤ Energy loss prior to entering TPC: 3.5% April 2016 and ICHEP ¤ Through-going muon contamination: 3% 2016 ¤ Wire chamber momentum uncertainty: 3% Paper in preparation Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 27

Highlight: Kaons 2 ⎛ ⎞ m = p c ⋅ TOF − 1 LArIAT Data ⎜ ⎟ ℓ c ⎝ ⎠ Preliminary LArIAT Data Preliminary Kaon Candidates ¤ Select kaons using tertiary beam TOF and magnetic spectrometer (wire chambers + magnets) Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 28

Highlight: Kaons Beam Direction LArIAT Data Preliminary LArIAT Data Preliminary Reconstruction K+ Candidate Scatter Scatter K + K + γ γ π + µ + π + µ + LArIAT Data Preliminary LArIAT Data Preliminary Reconstruction K+ Candidate Scatter Scatter γ γ K + K + π + π + γ γ ¤ Tagged as kaons entering TPC, then do PID by dE/dx-based “PIDA” algorithm (developed by ArgoNeuT) ¤ Demonstrated ability to automatically identify, tag, and reconstruct kaon events ¤ Next step: Kaon-Ar cross section Fermilab PAC Meeting, J. Raaf Nov. 11, 2016 29