Alpha-particle emission probabilities in the decay of Pu

Bratislava 09 September 2009 – ICRM2009 1

IRMM - Institute for Reference Materials and MeasurementsGeel - Belgium

http://irmm.jrc.ec.europa.eu/http://www.jrc.ec.europa.eu/

Alpha-particle emission probabilities in the decay of 240Pu

G. Sibbens, S. Pommé, T. Altzitzoglou, E. García-Toraño, H. Janßen, R. Dersch, O. Ott, A. Martín Sánchez, M.P. Rubio Montero, M. Loidl,

N. Coron, P. de Marcillac, T.M. Semkow


Decay scheme 240Pu


Alpha-particle emission probabilities and energies in the decay of 240Pu incorrect?

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.

Sibbens G., Pommé S. Study of alpha-particle emission probabilities and energies in the decay of 240Pu. Appl. Radiat. Isot. 60 (2004) 155-158.

101

103

102

104

105

100

α1

α2

5.04 5.07 5.10 5.165.13

Energy (MeV)

coun

ts

240Pu240Pu

239Pu

239Pu

239Pu

239Pu


EUROMET project 749

Alpha-particle emission probabilities in the decay of 240Pu

IRMM (co-ordinator), CIEMAT, PTB, Univ. of Extremadura, LNE/CEA-LIST, CNRS, NYSDOH

Project : experimental investigation by alpha-particle spectrometry

and a re-measurement of the alpha decay data of 240Pu

Deliverables : a new set of alpha-particle emission probabilities,

also for the less intense peaks


EUROMET project 749

Preparation of thin 240Pu sources

Alpha-particle spectrometry

Spectral analysis

New set of measured alpha-particle emission probabilities for 240Pu


240Pu material

0.0006

0.0560

Pu-241

0.0002

0.0100

Pu-242

0.151

0.002

Pu-238

0.028

0.102

Pu-239

99.83mass %

99.82α-activity %

Pu-240isotopes

Sibbens, G., Altzitzoglou, T., Benedik, L., Pommé, S., Van Ammel, R., 2008. α-particle and γ-ray spectrometry of a plutonium solution for impurity determination, Appl. Radiat. Isot. 66, 813-818.

Solution: 1.4 g 20 MBq/g Pu-240 in 1M HNO3

source preparation – spectrometry – spectral analysis – new set of Pα


240Pu sources

Substrate: material: quartzdiameter: 20 mmthickness: 1 mm

Sources: activity: 7.5 – 30 kBqactive diameter: 9 and 12 mmthickness: 3 µg/cm2

Pu-240 sources prepared by vacuum evaporation



Vacuum evaporation system at IRMM



Quality check 240Pu sources

autoradiograph: radioactivity distribution

microscope:material distribution



α-particle spectrometry

4.0 4.5 5.0 5.5

101

102

103

104

105

106

107

impu

ritie

s

IRMM 50 mm2

IRMM 150 mm2

CIEMAT 50 mm2

PTB 600 mm2

240Pu(n

orm

alis

ed) n

umbe

r of c

ount

s

Energy in MeV

LNE-LNHB Bolometer



Characteristics of 240Pu spectra

nr name detector area in mm2

Ω/4π #events FWHM in keV tailing

1 IRMM HR01 50 0.08 % 3.6×108 10.5 3×10-5 2 CIEMAT sum21 25 0.5 % 3.3×108 11.2 6×10-5 3 CIEMAT sum0106 50 0.5 % 4.3×108 11.2 1×10-4 4 CIEMAT sum1006 50 0.5 % 1.0×109 13.1 2×10-4 5 CIEMAT sum0326 100 1.3 % 1.7×109 14.1 1×10-4 6 PTB spectrum 600 0.47 % 3.4×108 21 1×10-5 7 IRMM HE01 150 2.2 % 1.7×1010 16.6 1×10-5



α-particle spectrometry

Pu240 IRMM HE01150 mm2 PIPS300 days

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

4800 4900 5000 5100 5200 5300

energy (keV)

coun

ts

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1.E+10

4200 4400 4600 4800 5000 5200

energy (keV)

coun

ts α5

α2

α8

α3α4α7

α2

α3

3.E+03

4.E+03

5.E+03

6.E+03

7.E+03

4200 4300 4400 4500 4600 4700 4800

energy (keV)

coun

ts

α4α5

α8α7

241+242Pu

Chechev, 2004

α0α1



γ-ray spectrometry

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

0 100 200 300 400 500 600 700 800 900 1000energy (keV)

cou

nts

Pu-240

HPGe-detector 36% relative efficiency for 60Co


γ2

γ1

γ3

γ4γ6

γ7


Spectral deconvolution algorithms

peak shapecodelab

2 exp. low-energy, 1 exp. high-energy tailing and step functionFit9PTB

Gaussian with 3 exponentials at low-energy sideFITBORUNEX

generalised exponent for alpha peak and generalised power function for the left tailGAPQNYSDOH

two-branch line shape

Gaussian with 3 exponentials at low-energy side

ALPACACIEMAT

ALPHAIRMM



Fitted peaks

Sum21_4

IRMM HR01


Spectrum: IRMM HR01Analysis code: CIEMAT ALPACA

Spectrum: CIEMAT sum21Analysis code: CIEMAT ALPACA


Fitted peaks

6800 6850 6900 6950 7000 7050 7100 7150

101

102

103

104

105

106

107

α149

α45

α0

num

ber o

f cou

nts

spectrum channel

-15

0

15

resi

dual

s


Spectrum: CIEMAT sum21Analysis code: IRMM ALPHA


Impurities in the 240Pu material


0.00060.0560Pu-2410.0100

0.102

0.002

99.83mass %

0.0002Pu-242

0.028Pu-239

0.151Pu-238

99.82Pu-240α-activity %isotopes

Gaussian shaped peaks

1.E+00

1.E+02

1.E+04

1.E+06

1.E+08

1.E+10

1.E+12

4200 4300 4400 4500 4600 4700 4800 4900 5000 5100 5200

Energy in keV

num

ber o

f cou

nts

Pu-240Pu-239Pu-241Pu-242

1.E+00

1.E+02

1.E+04

1.E+06

4800 4820 4840 4860 4880 4900 4920 4940

Energy in keV

num

ber o

f cou

nts


Coincidence summing effects


αTγ4,3 0.610 γ3,2 1.79γ2,1 11.24 γ1,0 604


Independent fit of tailing

10000

100000

4820 4840 4860 4880 4900 4920 4940

0

2000

4000

6000residuals

spectrum

α310

241,242Pu

240Pu

Energy in keV

num

ber o

f cou

nts


4500

5000

5500

6000

4450 4500 4550 4600 4650 4700

-150

0

150

300 residuals

spectrum

α522

α688240Pu

num

ber o

f cou

nts

Energy in keV

Spectrum: IRMM HE01


New set of Pα for 240Pu

branch DDEP 2008 this work Eα in keV Pα in % Pα in %

α688 4492.00 0.0000193 (4) ⎩⎨⎧

*(5) 0.000032(10) 0.000040

α522 4654.60 0.000047 (5) ⎩⎨⎧ <

* 10 1.72(7)10

6-

-5

α310 4863.51 0.001082 (18) 0.00097a (9) α149 50.21.15 0.0863 (18) 0.085 (4) α45 5123.64 27.16 (11) 27.21 (7) α0 5168.13 72.74 (11) 72.70 (7)

Chechev (2004)


* result obtained by γ-ray spectrometrya measured fraction was corrected for interfering 241Pu and 242Pu peaks and for estimated summing-out effects

Documents

Alpha-particle emission probabilities in the decay of Pu