Semin

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Seminární soustredení spolecného doktorského
projektu UTEF CVUT Praha a ÚJF AVCR Rež
Transmutation studies on JINR Dubna Phasotron

• Mitja Majerle

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Introduction

• Accelerator Driven Systems are modified classic
  reactors extra neutrons are added to the
  reactor
• The design of ADS is complicated, simplified and
  minimized setups for testing Dubna experiments
• Experiments protons (up to 1.5GeV), heavy metal
  target, activation detectors
• Phasotron experiment 660 MeV protons, intensive
  beam 10 min, samples of 127I and 129I in
  neutron field, focus on production of
  short-lifetime isotopes
• Analysis is long procedure, includes comparing
  results with computer simulated results

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Topics

• Overview of the experiment
• Analysis
• Number of protons
• Neutron field experiment, simulation
• Iodine samples
• Simulation codes

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Experiment characteristics

• Date and time 14th of December 2003 at 1633
• Intensive beam (2,61013 protons/s) of protons
  with energy 660 MeV from Phasotron
• Bare Pb target
• The irradiation time 10 minutes
• Measurements of iodine samples and foils in HPGe
  detectors

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Proton beam

• Measured with two foils (Al,Cu wider spectrum
  of reactions with protons) 1,581015 protons
  with accuracy 6
• Beam displacement (Al, Au, Bi foils) beam was
  shifted upwards, cca 1 cm

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Neutron field

• Al, Au, Bi foils
• Reactions 27Al n
• Spatial and energetic (from thermal (resonance)
  to 50 MeV) distribution of neutrons
• Maximum 8-10 cm
• Range of proton shower 30cm

Reaction products Threshold (MeV)
28Alg 0
27Mgp 1,89632
24Naa 3,24996
26Al2n 13,54607
... ...
Thresholds from http//t2.lanl.gov/data/data.htm
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Iodine samples

• 4 samples (2127I,2129I) 9th and 21st cm along
  the target
• From reactions (n,g) and (n,xn) we get iodine
  isotopes (all the way to 118I) which then decay
  (e, b, IT) towards the line of stability (blue
  elements)
• During the experiment 1/1011 part of the iodine
  nuclei transmuted

Stable
thours,days
tyears
tminutes
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Ratios of produced iodine isotopes

• 130I produced mostly in 129I samples (n,g) it
  decays b- to 130Xe
• With the exceptions of 130I and 128I, ratios of
  produced elements are higher in 127I samples
  (blue)

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MCNPX program code

• One of simulation codes for which such benchmark
  tests are done
• Used as a tool at planning of experiments
• Implemented all the time, experiments are
  simulated under different versions
• Simulated spectrum, calculated yields of produced
  elements -gt simulate the yields
• Results suit well experiments (DCM)

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Conclusion

• The experiment on Phasotron will serve as a good
  benchmark test
• Proton beam intensive, but well focused
• Neutrons experimental data agree with
  expectations from previous experiments and with
  simulation
• Iodine detected short lived isotopes
• The data was presented at two international
  conferences 7th Session of AER working group
  for spent fuel transmutation (the Czech
  Republic), 17th Baldin seminar (Russia) Than
  k you.