EUROMET 749: Alphaparticle emission probabilities and energies in the decay of 240Pu Goedele Sibbens

1
EUROMET 749 Alpha-particle emission
probabilities and energies in the decay of 240Pu
Goedele Sibbens
2
EUROMET project no 749
Collaboration type co-operation in
research Date project started 1.1.2004 Co-ordinat
or Goedele Sibbens Participants IRMM
(EC) CIEMAT (Spain) Univ. of Extremadura UNEX
(Spain) NPL (UK) PTB (Germany)
3
EUROMET project no 749
Pa and Ea in the decay of 240Pu

• Measurements at IRMM of the alpha-particle
  emission probabilities and energies in the decay
  of 240Pu reveal a discrepancy with published
  evaluated data, but agree with measured data by
  Bland et al. (1992).
• Project experimental investigation by
  alpha-particle spectrometry and a re-evaluation
  of the alpha decay data of 240Pu.
• Deliverables a better set of alpha-particle
  emission probabilities and energies, also for the
  less intense peaks.

4
High resolution a spectrum of 239,240Pu
Bortels, G., Verbruggen, A., Sibbens, G.,
Altzitzoglou, T.,1996. EUROMET Project No 325
Analysis of Plutonium Alpha-Particle Spectra.
IRMM Internal Report GE/R/RN/01/96.
5
Residuals literature decay data vs. free fit
Sibbens G., Pommé S. Study of alpha-particle
emission probabilities and energies in the decay
of 240Pu. Appl. Radiat. Isot. 60 (2004) 155-158.
6
Tasks within the EUROMET project no 749
7
Source preparation
Pu-240 sources prepared by vacuum
evaporationSolution 20 MBq/g Pu-240
in 1M HNO3 Substrate material
quartz diameter 20 mm thickness 1 mm
Sources activity 7.5 30 kBq active
diameter 9 and 12 mm thickness 1 3 mg/cm2
8
Quality check of the Pu-240 sources
microscope material distribution
autoradiograph radioactivity distribution
9
Isotopic composition of the Pu solution

Am-241
10
Impurities in the Pu-240 spectrum
computer generated spectrum
11
Measured spectrum
Pu-240
FWHM 9 keV
tailing hides small peaks
12
Status of the EUROMET project no 749
13
a-measurements at IRMM
14
150 mm2 PIPS
Pu-240
Am-241
pile-up
tailing hides small peaks
50 days
15
50 mm2 PIPS
Pu-240
tailing hides small peaks
27 days
16
g-measurements at IRMM
17
g-measurements at IRMM
Pu-240
18
Pu-240 decay g-emissions
Table de Radionucléides 1986
19
EUROMET project no 749 Project planning