Discussion: Open physics questions in the liquid nobles.

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DiscussionOpen physics questions in the liquid
nobles.

• T. Shutt
• Case Western Reserve University

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Why we shouldnt talk about quenching

• Lindhard nuclear recoils give less electronic
  excitation than electron recoils.
• Not a quenching process
• Recombination creates one photon from one
  electron
• Also not a quenching
• Quenching from exciton-exciton interactions may
  be present (Hitachi)
• In organic liquid scintillators, is a quenching
  process that loses light for dense tracks
  (alphas, nuclear recoils).

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Charge and light yield phenomena
(excitons)

• Recombined ionization gives light.
• Most signal is initially ionization.
• Nex/Ni - fraction directly into excitons 10
  Xe, 21 Ar
• Recombination is not complete, even at zero
  field escape electrons
• Ni0/Ni - fraction of escape electrons 10
  (Case) 0.43 (1 MeV -Doke) Xe, Ar 26
• Doke timescale of gt ms.

(Doke - Jpn.J.Appl. Phys. 41 p1538 2002)
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Questions

• What is the origin of PSD in noble liquids?
• Is is independent of recombination, and if so,
  how?
• Is PSD affected by recombination fluctuations?
• What about the recombination timescale?
• Is the direct exciton fraction (and escape
  electron fraction) the same for nuclear recoils
  and electron recoils?
• Is this related to the (nearly complete)
  field-independence of the charge collection for
  nuclear recoils?
• Do we have a complete energy picture - in Xe? in
  Ar? (and Ne?)
• Is Lindhard correct? Is Hitachi quenching
  present?
• Could the high light yield in Ar possible?
• Is the escape electron fraction in zero-field nr
  measurements 20 in Xe? In Ar?
• What can we learn from the gas phase?

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