Evaluation of the absolute emission probability of 1077 keV -ray for 68Ga

Huang Xiaolong

2013， 6

China Nuclear Data CenterChina Institute of Atomic Energy, P.O. Box 275(41), Beijing 102413, Chinae-mail: huang@ciae.ac.cn

2

Status

P(511) P(1077) Comments

1994Sc44 89.14 11 3.22 3 Absolute Exp.

2012Lu14 90.5 30 3.25 11 Absolute Exp.

Jiang(2011) 89.4 2.56 9 deduced

Table of Isotope, 7th edition

89.3 16 3.0 3 Eval.

NDS 88.9 3.22 3 Eval.

DDEP 89.14 11 3.22 3 Eval.

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B ackground

+

1077keV ,3~3.2%

+ ,1077keV =2.56%,China

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Reason ?

a large difference between the cross section deduced with 511keV and 1077keV -ray is up to ~30%

Maybe the current decay data of 68Ga, that’s the P (1077keV), has a problem.

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Jiang’s Measurement

Cross section exp.: Irradiation of the samples(Ga2O3 powder ) was carried out at Cockcraft-Walton accelerator in CIAE and lasted 40 min.

The finial results of 69Ga(n,2n)68Ga reaction c-s at En=14.9MeV was 103031(mb) with P (1077keV)= 2.560.09%.

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Exp. data status on relative -ray intensities

LRSW results are in good agreement with Jiang’s exp. and NDS eval. This means the present exp. data on relative -ray intensities are good.

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Eval. P(1077keV)-1

The available measured I+ values are little changed: I+=8811%(1959Ra), 89.2%(1969Va16), 89.140.11%

(1994Sc44 )

Assumed: I+= 89.140.11%. From LOGFT,

/+(1077keV level) =1.505, /+(ground state)=0.1017, and

-ray intensity balance, deduced

P(1077keV)=2.810.01%

This value is obviously different from the absolute measuremed value:3.220.03%, or Jiang’s deduced value: 2.560.09%.

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Eval. P(1077keV)-2

In order to eval. the P(1077keV), the measured ratio of the intensity for positrons(pann) and intensity for 1077keV(p1077) are considered.

The weighted average results are adopted as the measured values are discrepant.

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Eval. P(1077keV)-3

Consider: Pann/P1077=65.60.4 %. From LOGFT,

/+(1077keV level) =1.505, /+(ground state)=0.1017, and -ray intensity balance, deduced

P(1077keV)=2.720.16 % I+=89.20.2%

Also, this value is different from the absolute measuremed value:3.220.03%, or Jiang’s deduced value: 2.560.09%.

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Discussion -1

In order to verify the rationality of our eval., mainly C-S measurements ~14.8MeV are adjusted using present eval.

It’s obvious that the good agreement is obtained.

Thus, present evaluated P(1077keV) is considered superior to

other evaluations such as NDS/DDEP.

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Discussion-2

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谢谢！