Study of bubble distributions by high-energy protons in bubble detectors and its hints in neutron detection at higher altitude and in space

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Study of bubble distributions by high-energy
protons in bubble detectors and its hints in
neutron detection at higher altitude and in space

• S.-L. Guo
• China Institute of Atomic Energy, Beijing, China
• T. Doke et al., Waseda University, Tokyo, Japan
• D.-H. Zhang, Shanxi Normal University, Linfen,
  China
• M. Komiyama, RIKEN, Japan
• N. Yasuda et al., NIRS, Japan

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1. Introduction
Primary Cosmic Rays Secondary Cosmic Rays
n ? bubbles p ? ? dose
This work
BD
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2. Bubble Detectors and Irradiation
Large size BD China Institute of Atomic
Energy
23 cm
Stop
trajectory track
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• Irradiation
• p cyclotron, RIKEN, Japan

Cyclotron Scint. D Stopper
BD
Acrylic AlAl
p
stop
210 MeV
105.5 MeV
Arrangement of irradiation
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p T -14
3. Bubble distribution and categories
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(No Transcript)
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Bubble distribution and categories
T-24
Fluence 8,333 p/cm2 8,333 2,083 416.7 83.3 41.7
p
high density low density

• Random
• Abrupt change , density
• L R
• (4) fluence, p/cm2

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Bubble categories
(1) Scattering bubbles
(2) Recoil bubbles
(3) Intrinsic bubbles
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4. Bubble density distribution
T-14
T-24
T-12

• Two terraces
• Steep drop
• Higher terrace Recoil bubbles Scattering
  bubbles Intrinsic bubbles
• Lower terrace
  Scattering bubbles Intrinsic
  bubbles
• __________________________________________________
  _____________________
• Difference Recoil bubbles
• Recoil
  bubble density ----- unique

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5. Results of measurements
Bubble detector Energy of protons Fluence of protons Visible depth Volume of measurement Density of scattering bubbles Density of Recoil bubbles Detection efficiency for protons
MeV 103 cm-2 mm cm3 cm-3 cm-3 (bubble/cm3)/(proton/cm2)
T-14 105.5 8,3330.019 41 2.360.64 28.08.2 7723 (0.930.27)10-2
T-24 105.5 2.0830.010 41 1.270.34 30.49.7 9530 (4.61.5)10-2
T-12 105.5 2.0830.010 31 1.650.57 3312 9736 (4.71.7)10-2

• Detection efficiency for protons via recoil
  bubbles

T-14 0.930.2710-2
T-24 4.6 1.5 10-2
T-12 4.7 1.7 10-2
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6. Comparison with detection efficiency for
neutrons

• T-12 2 R-12
• 20 keV 19 MeV

0.3 19 MeV
100 times
higher for protons Origin Rutherford
scattering p C, F,
Cl ? Recoil nuclei ?bubbles.
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7. Conclusions

• (1) 3 types of BD p
• Proton delection efficiencies
• Neutron detection efficiency
• (4) Rutherford scattering !!!
• Cosmic ray protons
  ? forming bubbles !!!
• Space neutron dose
  ??? bubble number
• 
  Non Simple

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• Thanks