E-dep of Mu formation in Cryocrystals

• Condensed Rare Gases

  • Liquid neon (l-Ne) as compared with
  • Solid neon (s-Ne)

  • Liqid argon (l-Ar)
  • Solid argon (s-Ar)

  • Solid krypton (s-Kr) and Solid xenon (s-Xe) show no detectable E-dependence of the Mu formation probability, which is close to 100% in each case. This presumably means that the µ⁺ stops very close to the last e^- it liberates in its ionization track. This may indicate a more efficient moderation mechanism in the heavier RGS or it may simply reflect the lower ionization potential of Kr and Xe (the muon continues to liberate electrons down to lower energy and is therefore closer to the end of its range when it makes the last one).

• Molecular Solids

  • Solid nitrogen (s-N₂)

  • Dry ice (s-CO₂)

  • Solid deuteromethane (s-CD₄) compared with s-N₂ and the RGS.