Decay Data Evaluation Project (DDEP): Evaluation of the main 243Cm and 245Cm decay characteristics

Chechev, V. P.

doi:10.1016/j.apradiso.2012.02.031

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…; (2) library name (CENDL-DDL1.0), material number, date type (i.e., radioactive decay data), and format type (ENDF-6); (3) detailed comments on the evaluation; (4) specific decay data not contained in the main decay data section and consistency check of the recommended data set. In the data section (MF=8, MT=457), the recommended decay data for the following characteristics are listed for each nuclide: (1) Spin and parity of the level of parent nuclide; (2) half-life of the level of the parent nuclide in second unit; (3) mean energy for γ (including Xray) and β (or heavy) particles; (4) decay mode, decay energy (Q-values), branching fraction, and isomeric branching fraction for isomeric state; (5) energy and emission probability of γ-ray; (6) energy, emission probability, and transition type of β-particle; (7) energy, emission probability, and transition type of electron-capture; (8) energy and emission probability of α-particle; (9) energy and emission probability of delay-neutron; (10) energy and emission probability of delay-proton; (11) energy and emission probability of discrete-electron; (12) energy and emission probability of X-ray.…”

Section: B Data Processing Methodsmentioning

confidence: 99%

Nuclear decay database in fission product mass region*

Huang 黄,

Yang 杨,

Ge 葛

et al. 2024

Chinese Phys. C

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ccurate and reliable nuclear decay database is essential for fundamental and applied nuclear relative researches. However, the decay data is not as accurate as usual impression and still need improvement. Hence, the new Chinese nuclear decay database in fission product mass region (A=66-172) has been developed under the joint efforts of CNDC working group, based on several major national evaluated data libraries. Totally 2358 nuclides have been included in this decay database. Two main data formats, ENSDF and ENDF, are adopted. For the total mean  and  energies, data from total absorption gamma ray spectroscopy measurement are adopted when available. For some nuclides without experimental measurements, theoretically calculated values were added.

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Section: B Data Processing Methodsmentioning

confidence: 99%

Nuclear decay database in fission product mass region*

Huang 黄,

Yang 杨,

Ge 葛

et al. 2024

Chinese Phys. C

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“…[66], and the weighted average calculated by Ref. [68]. The thick line is the weighted average of all the present experimental runs and the dotted lines are the total uncertainty on the weighted average.…”

Section: Literature Valuesmentioning

confidence: 88%

“…[66] and [68] to calculate the weighted average. In the 240 Pu case the literature values correspond to: Fieldhouse (1967) [69], Budtz-Jørgensen (1980) [25], Androsenko (1984) [70], Selickij (1988) [71], Dytlewski (1989) [72], Ivanov (1991) [73] and Holden (2000) [66], and Chechev (2009) [68]. The literature values for the 242 Pu are: Studier (1956) (cited by Ref.…”

Section: Literature Valuesmentioning

confidence: 99%

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Neutron-induced fission cross section of 240,242Pu

Salvador Castiñeira

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A recent sensitivity analysis done for the new generation of fast reactors [1] has shown the importance of improved cross section data for several actinides. Among them, the neutron-induced fission cross section of 240,242Pu requires a level of accuracy of 1-3% and 3-5%, respectively, from the current status of 6% and 20%. Moreover, nearly all the measurements in the literature have been done relative to 235U(n,f). Therefore, using other references samples such as 237Np or 238U will provide the scientific community with more valuable data. The work was carried out at the Institute for Reference Materials and Measurements (JRC-IRMM). The Van de Graaff accelerator was used for producing a quasi-monoenergetic neutron flux in the energy range of 0.3MeV to 3MeV. Protons were accelerated thanks to a potential difference. A neutron producing target was placed at the end of the beam line: 7Li(p,n)7Be or T(p,n)3He. Then, a twin Frisch-grid ionization chamber (TFGIC) was used as detector. The setup of the detector consists in a common cathode, two anodes and two grids. In the cathode the sample under study and the reference sample are placed in a back-to-back configuration. Each electrode is connected to a preamplifier, and then to a 100MHz 12 bit waveform digitizer. All raw signals are stored for an offline analysis using C++ under the ROOT framework. All the samples used were produced by the target preparation group at JRC-IRMM. The enrichment of the plutonium samples was of 99.89% for 240Pu and of 99.97% for 242Pu. The plutonium masses were chosen to minimize their alpha activity (0.8MBq for 240Pu and 0.1MBq for 242Pu). Three different reference fission cross sections were employed: 235U(n,f), 238U(n,f) and 237Np(n,f). The mass of all the reference samples used was remeasured by means of low geometry alpha counting or/and by a single grid ionization chamber. The mass uncertainty of each sample was lower than 2%. Results were obtained not only for the neutron-induced fission cross section of 240,242Pu in the region from 0.3 MeV up to 3 MeV, but for the 238U(n,f) cross section and the 237Np(n,f) cross section. The neutron flux from the Van de Graaff was characterized by means of MCNP simulations. A clear influence of the different structures between the neutron producing targets and the deposits was found, specially when the ratios measured involved a fissile sample and a threshold sample. The spontaneous fission of 240,242Pu is, as well, an important correction. Thus, this property was measured independently in this work, reaching an uncertainty lower than 1.3% for both isotopes. More corrections were due to the high electronic threshold needed to not trigger on alpha particles, the fission fragment loss due to the sample thickness, neutron emission anisotropy, etc. On average the results of the 240,242Pu(n,f) cross section are in agreement with previous experimental data, even though the trend is slightly lower than present evaluations. In the case of 242Pu(n,f) cross section the resonance-peak structure at 1.1 MeV could not be reproduced in any case. The results of the 237Np(n,f) cross section show an increase at the plateau region with respect to the ENDF/B-VII.1 evaluation in the same way as the data from Paradela (2010) [2]. The results for the 238U(n,f) cross section show a higher cross section than the ENDF evaluation but in agreement with the present JEFF 3.2 evaluation. [1] Uncertainty and target accuracy assessment for innovative systems using recent covariance data evaluations, Volume 26, 2008, OECD-NEA [2] Paradela, C. et al., Neutron-induced fission cross section of U-234 and Np-237 measured at the CERN Neutron Time-of-Flight (n_TOF) facility.,Physical Review C. 82, 3, 034601 (2010) Un anàlisi de sensitivitat [1] recent per la nova generació de reactors ràpids va mostrar la importància de millorar les seccions eficaç de varis actínids. Entre ells, la secció eficaç de fissió per neutró induït del 240,242Pu requereix una millora en la seva precisió des d'un 6% a un 1-3% pel 240Pu i des d'un 20% a un 3-5% pel 242Pu. A més, quasi bé totes les dades experimentals disponibles a la literatura han estat determinades relatives a la secció eficaç del 235U(n,f). Per tant, la utilització d'altres isòtops com a referències, tal com el 237Np(n,f) o el 238U(n,f), proveirà a la comunitat científica amb dades valuoses. Aquest treball ha estat realitzat a l'Institute for Reference Materials and Measurements (JRC-IRMM). L'accelerador Van de Graaff disponible al JRC-IRMM s'ha emprat per produir un flux de neutrons quasi mono-energètics en el rang de 0.3 MeV a 3 MeV. Els protons van ser accelerats de fer-los impactar amb una mostra de producció de neutrons: 7Li(p,n)7Be o T(p,n)3He. A continuació, una doble cambra d'ionització amb grid (TFGIC) es va emplaçar com a detector consistent en un càtode, dos ànodes i dos grids. En el càtode es situen la mostra a estudiar i la mostra de referència. Cada un dels elèctrodes és connectat a un preamplificador i, a continuació, a un digitilitzador amb una freqüència de 100 MHz i 12 bit. Les senyals originals són emmagatzemades sense cap tractament previ per a un posterior anàlisi. El tractament de dades es va realitzar mitjançant el codi de programació C++ sota el marc de ROOT. Totes les mostres emprades en aquest experiment s'han produït al grup de preparació de mostres del JRC-IRMM. L'enriquiment de les mostres de plutoni era de 99.89% pel 240Pu (0.8MBq) i del 99.97% pel 242Pu (0.1MBq). La massa de les tres mostres de referència (235U(n,f), 238U(n,f) i 237Np(n,f)) també va ser mesurada. La incertesa de cada massa és inferior al 2%. La principal correcció aplicaca als resultats obtinguts ha estat per la caracterització del flux de neutrons mitjançant el codi de simulació Monte Carlo MCNP. Els resultats de les simulacions han mostrat una clara influència de les diferents estructures emplaçades entre la mostra de producció de neutrons i les mostres de fissió. Altres correccions s¿han realitzat per la fissió espontània del 240,242Pu (mesurada independentment en aquest treball amb una incertesa inferior al 1,3%), la deficiència d'esdeveniments a causa del llindar de detecció, l'eficiència del detector, l'anisotropia en l'emissió dels neutrons, etc. Tot i que el principal objectiu va ser l'obtenció de la secció eficaç de fissió per neutró induït del 240,242Pu en la regió de 0.3 MeV a 3 MeV, resultats addicionals han estat obtinguts per la secció eficaç del 238U(n,f) i el 237Np(n,f). Els resultats obtinguts mostren un acord significatiu entre la secció eficaç del 240,242Pu(n,f) i resultats experimentals anteriors, tot i que la tendència és lleugerament inferior a les avaluacions (ENDF/B-VII.1, JEFF 3.1 i JENDL 4.0) disponibles. En el cas de la secció eficaç del 242Pu(n,f), a més, el pic de ressonància al voltant de 1.1 MeV predit per quasi totes les dades experimentals anteriors i les avaluacions actuals no s'ha reproduït en aquest experiment. Els resultats de la secció eficaç del 237Np(n,f) presenten un increment en la regió plana després del llindar de fissió d'un 5-7% respecte l'avaluació ENDF/B-VII.1, i en concordança amb els resultats obtinguts per Paradela (2010) [2]. Finalment, els resultats de la secció eficaç del 238U(n,f) mostren un increment al voltant d'un 7-9% a la zona plana després del llindar de fissió, aquesta predicció concorda amb l'avaluació JEFF 3.2. [1] Uncertainty and target accuracy assessment for innovative systems using recent covariance data evaluations, Volume 26, 2008, OECD-NEA [2] Paradela, C. et al., Neutron-induced fission cross section of U-234 and Np-237 measured at the CERN Neutron Time-of-Flight (n_TOF) facility.,Physical Review C. 82, 3, 034601 (2010)

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Nuclear Data Sheets for A = 239

Browne

Tuli

2014

Nuclear Data Sheets

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A b s t r a c t : S p e c t r o s c o p i c d a t a a n d l e v e l s c h e m e s f r o m r a d i o a c t i v e d e c a y a n d n u c l e a r r e a c t i o n s t u d i e s a r e presented here for all nuclei with mass number A=239. I n g e n e r a l , a r e l a t i v e l y s m a l l a m o u n t o f n e w d a t a o n t h i s m a s s c h a i n h a s b e e n r e p o r t e d s i n c e t h e p r e v i o u s e v a l u a t i o n i n 2 0 0 3 . H o w e v e r , s p e c i a l e v a l u a t i o n s , s u c h a s " D a t a b a s e o f p r o m p t g a m m a r a y s f r o m s l o w neutron-capture from elemental analysis" (2007ChZX), have provided additional precise data for levels in 2 3 9 U. Also, new Coulomb excitation measurements in 239 Pu have extended the knowledge of the 1/2[631] rotational band up to Jπ =(55/2+), and that of the octupole vibrational band up to Jπ =(53/2-).F o r h i s t o r i c a l k n o w l e d g e i t i s w o r t h m e n t i o n i n g t h e r e p o r t o n t h e " D i s c o v e r y o f i s o t o p e s o f t h e t r a n s u r a n i u m elements with 93<= Z <=98" (2013Fr02), where the information for elements Np, Pu, Am, and Cf with mass number A=239 is presented.

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Decay Data Evaluation Project (DDEP): Evaluation of the main 243Cm and 245Cm decay characteristics

Cited by 5 publications

References 28 publications

Nuclear decay database in fission product mass region*

Nuclear decay database in fission product mass region*

Neutron-induced fission cross section of 240,242Pu

Nuclear Data Sheets for A = 239

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