Measurement of neutron capture cross section of 187W for production of 188W

Onur Alp Ersöz; Robyn Spink; Justin R. Griswold; Fatma Yurt; Saed Mirzadeh

doi:10.1016/j.apradiso.2019.03.039

Measurement of neutron capture cross section of ¹⁸⁷W for production of ¹⁸⁸W

Onur Alp Ersöz, Robyn Spink, Justin R. Griswold, Fatma Yurt, Saed Mirzadeh

Target Design, Analysis, and Qualificati

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

Tungsten-188 (t_1/2 = 69.4 d) is routinely produced by double neutron capture using highly enriched ¹⁸⁶W target, ¹⁸⁶W(n,γ)¹⁸⁷W(n,γ)¹⁸⁸W reaction, at the ORNL 85 MWt High Flux Isotope Reactor. While the thermal neutron cross section for the first reaction, ¹⁸⁶W(n,γ)¹⁸⁷W, is well known, the single reported 64 b cross-section for the second reaction, ¹⁸⁷W(n,γ)¹⁸⁸W, cannot be validated by experimental results that yield lower than expected activities of ¹⁸⁸W. In this study, we report a new value for the thermal neutron capture cross section of ¹⁸⁷W. After confirming the neutron capture cross section of ¹⁸⁶W (σ⁰ = 37.8 ± 1.8 b for thermal and I⁰ = 476 ± 25 b for resonance integrals with σ⁰/I⁰ = 12.6 ± 0.4) in two short irradiations, longer irradiations (1–10 d) were performed to obtain a value of 6.5 ± 0.8 b for the σ⁰ of ¹⁸⁷W, which is lower than the adopted value by a factor of 10. Due to the short half-life of ¹⁸⁷W (t_1/2 = 23.7 d), the σ⁰ for ¹⁸⁷W was obtained empirically by comparing the ¹⁸⁸W experimental yields with the theoretical yields generated by code IsoChain and varying the ¹⁸⁷W cross section while keeping all other parameters constant.

Original language	English
Pages (from-to)	191-196
Number of pages	6
Journal	Applied Radiation and Isotopes
Volume	148
DOIs	https://doi.org/10.1016/j.apradiso.2019.03.039
State	Published - Jun 2019

Funding

This research was supported by DOE , Office of Nuclear Physics, Isotope Program, under contract DE-AC05-00OR22725 and TÜBITAK (The Scientific and Technological Research Council of Turkey) and Project Number: 1059B141600608 . The authors acknowledge the efforts and support of the High Flux Isotope Reactor staff, especially Greg Hirtz, for scheduling the irradiations of the targets, and staff of Nuclear and Radiochemistry Group for help in many aspects of this project, especially Allison Peacock and Lance Wyant for handling the irradiated targets in the hot cell. The authors thank James Gaugler II and Riley Hunley for their critical review of the manuscript.

Funders	Funder number
U.S. Department of Energy
Nuclear Physics	DE-AC05-00OR22725
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu	1059B141600608

Keywords

Empirical measurement
High flux isotope reactor (HFIR)
IsoChain
Neutron capture cross-section
Neutron induced nuclear reaction
Tungsten-187
Tungsten-188

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10.1016/j.apradiso.2019.03.039

Cite this

@article{8cd6ddab1642412e9a6b09a10dee1041,

title = "Measurement of neutron capture cross section of 187W for production of 188W",

abstract = "Tungsten-188 (t1/2 = 69.4 d) is routinely produced by double neutron capture using highly enriched 186W target, 186W(n,γ)187W(n,γ)188W reaction, at the ORNL 85 MWt High Flux Isotope Reactor. While the thermal neutron cross section for the first reaction, 186W(n,γ)187W, is well known, the single reported 64 b cross-section for the second reaction, 187W(n,γ)188W, cannot be validated by experimental results that yield lower than expected activities of 188W. In this study, we report a new value for the thermal neutron capture cross section of 187W. After confirming the neutron capture cross section of 186W (σ0 = 37.8 ± 1.8 b for thermal and I0 = 476 ± 25 b for resonance integrals with σ0/I0 = 12.6 ± 0.4) in two short irradiations, longer irradiations (1–10 d) were performed to obtain a value of 6.5 ± 0.8 b for the σ0 of 187W, which is lower than the adopted value by a factor of 10. Due to the short half-life of 187W (t1/2 = 23.7 d), the σ0 for 187W was obtained empirically by comparing the 188W experimental yields with the theoretical yields generated by code IsoChain and varying the 187W cross section while keeping all other parameters constant.",

keywords = "Empirical measurement, High flux isotope reactor (HFIR), IsoChain, Neutron capture cross-section, Neutron induced nuclear reaction, Tungsten-187, Tungsten-188",

author = "Ers{\"o}z, {Onur Alp} and Robyn Spink and Griswold, {Justin R.} and Fatma Yurt and Saed Mirzadeh",

note = "Publisher Copyright: {\textcopyright} 2019",

year = "2019",

month = jun,

doi = "10.1016/j.apradiso.2019.03.039",

language = "English",

volume = "148",

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journal = "Applied Radiation and Isotopes",

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T1 - Measurement of neutron capture cross section of 187W for production of 188W

AU - Ersöz, Onur Alp

AU - Spink, Robyn

AU - Griswold, Justin R.

AU - Yurt, Fatma

AU - Mirzadeh, Saed

PY - 2019/6

Y1 - 2019/6

N2 - Tungsten-188 (t1/2 = 69.4 d) is routinely produced by double neutron capture using highly enriched 186W target, 186W(n,γ)187W(n,γ)188W reaction, at the ORNL 85 MWt High Flux Isotope Reactor. While the thermal neutron cross section for the first reaction, 186W(n,γ)187W, is well known, the single reported 64 b cross-section for the second reaction, 187W(n,γ)188W, cannot be validated by experimental results that yield lower than expected activities of 188W. In this study, we report a new value for the thermal neutron capture cross section of 187W. After confirming the neutron capture cross section of 186W (σ0 = 37.8 ± 1.8 b for thermal and I0 = 476 ± 25 b for resonance integrals with σ0/I0 = 12.6 ± 0.4) in two short irradiations, longer irradiations (1–10 d) were performed to obtain a value of 6.5 ± 0.8 b for the σ0 of 187W, which is lower than the adopted value by a factor of 10. Due to the short half-life of 187W (t1/2 = 23.7 d), the σ0 for 187W was obtained empirically by comparing the 188W experimental yields with the theoretical yields generated by code IsoChain and varying the 187W cross section while keeping all other parameters constant.

AB - Tungsten-188 (t1/2 = 69.4 d) is routinely produced by double neutron capture using highly enriched 186W target, 186W(n,γ)187W(n,γ)188W reaction, at the ORNL 85 MWt High Flux Isotope Reactor. While the thermal neutron cross section for the first reaction, 186W(n,γ)187W, is well known, the single reported 64 b cross-section for the second reaction, 187W(n,γ)188W, cannot be validated by experimental results that yield lower than expected activities of 188W. In this study, we report a new value for the thermal neutron capture cross section of 187W. After confirming the neutron capture cross section of 186W (σ0 = 37.8 ± 1.8 b for thermal and I0 = 476 ± 25 b for resonance integrals with σ0/I0 = 12.6 ± 0.4) in two short irradiations, longer irradiations (1–10 d) were performed to obtain a value of 6.5 ± 0.8 b for the σ0 of 187W, which is lower than the adopted value by a factor of 10. Due to the short half-life of 187W (t1/2 = 23.7 d), the σ0 for 187W was obtained empirically by comparing the 188W experimental yields with the theoretical yields generated by code IsoChain and varying the 187W cross section while keeping all other parameters constant.

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KW - High flux isotope reactor (HFIR)

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