Space Charge Effects at DUNE FD from Cosmics and Ar-39 Michael - - PowerPoint PPT Presentation

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Space Charge Effects at DUNE FD from Cosmics and Ar-39 Michael - - PowerPoint PPT Presentation

May 28, 2023 177 likes •278 views

Space Charge Effects at DUNE FD from Cosmics and Ar-39 Michael Mooney Colorado State University DUNE Calibration Task Force Meeting October 24 th , 2017 1 Introduction Introduction Space charge effects are big at ProtoDUNEs up to 20

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Space Charge Effects at DUNE FD from Cosmics and Ar-39

Michael Mooney

Colorado State University

DUNE Calibration Task Force Meeting October 24th, 2017

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Introduction Introduction

♦ Space charge effects are big at ProtoDUNEs – up to 20 (60) cm spatial distortions for SP (DP), at 500 V/cm ♦ But what about for DUNE FD? Expect to be small, but how small? Present studies with simulation in these slides ♦ Topics like these discussed in ProtoDUNE DRA meetings

  • Thursdays at 8 am CT – please join the conversation!

Toy MC Calibration (ProtoDUNE-SP): 10000 Isotropic Muons with no MCS

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Some Numbers Some Numbers

♦ Start with some simple calculations ♦ Expected cosmic rate at DUNE FD (one 10 kt module):

  • If on surface: O(30000)/second (projection from μBooNE)
  • On 4850L: O(4000)/day → O(0.01)/second

♦ Space charge scales with cosmic rate, and is roughly three million times less bad than if on surface. Negligible!

  • Effect highly stochastic/local (unlikely to impact ν events)

♦ What about contribution from Ar-39?

  • Assume 1 Bq/kg → ten million decays/second in DUNE FD
  • Roughly 1.0 × 10-12 C/m3/s vs. 2.0 × 10-10 C/m3/s from cosmics on

surface → small, but might not be negligible

♦ Study SCE sim. using prediction of space charge from Ar-39

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SCE for DUNE SP FD SCE for DUNE SP FD

♦ DUNE SP FD – looking at one half of central Z slice

  • APA+CPA+APA

♦ E field distortions on order of 0.1% – very small!

  • Impact on dQ/dx from recombination ~ 0.03%
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SCE for DUNE SP FD (cont.) SCE for DUNE SP FD (cont.)

♦ DUNE SP FD – looking at one half of central Z slice

  • APA+CPA+APA

♦ Spatial distortions on order of 1.0-1.5 mm – very small!

  • Total impact on dQ/dx (including recomb.) < 0.1%
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SCE for DUNE DP FD SCE for DUNE DP FD

♦ DUNE DP FD – looking at full detector, central Z slice

  • Ionization drift is to the left (anode on left, cathode on right)

♦ E field distortions on order of 1% – larger than for SP case

  • Impact on dQ/dx from recombination ~ 0.3%
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SCE for DUNE DP FD SCE for DUNE DP FD

♦ DUNE DP FD – looking at full detector, central Z slice

  • Ionization drift is to the left (anode on left, cathode on right)

♦ Spatial distortions on order of 5 cm – not negligible!

  • Total impact on dQ/dx (including recomb.) ~ 2-3%
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Putting Ar-39 To Use? Putting Ar-39 To Use?

♦ While the main contributor for SCE, can use Ar-39 as calibration source at DUNE FD – O(100,000)/event

  • e.g. electron lifetime measurement (Ar-39 uniform in x direction)
  • CSU undergraduate, Alex Flesher, and Mike M. studying this with

MicroBooNE data (preliminary report later this week)

♦ Ar-42 for higher energy calib.? ~100 μBq/kg, O(10)/event

Ar-39 DUNE SP FD Ar-39 DUNE DP FD Ar-42 DUNE SP FD

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Summary Summary

♦ Space charge at DUNE FDs dominated by Ar-39 decays ♦ SCE in SP DUNE FD negligible ♦ SCE in DP DUNE FD not negligible and likely needs calibration to pin down dQ/dx to 2% or below ♦ Can we use Ar-39 (and Ar-42) as a calibration source at the DUNE FDs?

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BACKUP SLIDES

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