Request ID	10		Type of the request	General request
Target	Reaction and process	Incident Energy	Secondary energy or angle	Target uncertainty	Covariance
79-AU-197	(n,tot) SIG	5 keV-200 keV		5
Field	Subfield	Date Request created	Date Request accepted	Ongoing action
Fusion,Science	Dosimetry	18-MAY-07	06-JUN-07

Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org

Project (context): Dosimetry

Impact:
INDC(NDS)-0507 Summary Report of Consultants’ Meeting Review the Requirements to Improve and Extend the IRDF library (International Reactor Dosimetry File (IRDF-2002)), IAEA Headquarters, Vienna, Austria 20-21 April 2006, prepared by L.R. Greenwood and Alan L. Nichols (IAEA, Vienna, January 2007)

Accuracy:
5%

Justification document:
Gold is an extremely important material in nuclear applications: the capture on gold is a standard neutron cross-section, gold has been proposed as a high energy neutron dosimeter (see below), Au-197(n,2n) is a reactor dosimetry reaction considered in all recent IRDF files, etc. Reactions on gold are also of interest for nuclear model code testing as gold is a mono-isotopic element being amenable to detailed calculations.
Taken from INDC(NDS)-0507 "... proposed high energy dosimetry reactions 197Au(n,2n)196Au, 197Au(n,3n)195Au, and 197Au(n,4n)194Au require the extension of the gold evaluation up to 60 MeV"
To our surprise we found large discrepancies in the measured total cross section data of gold in the 5-200 keV energy range (URR) as can be seen from the attached plots. The only existing evaluation (Young et al in red in the figures) has been carried out in the early nineties and has been adopted for all subsequent libraries with minor modifications. This evaluation follows the Seth et al. data measured in 1965, which is in contradiction with several new measurements (for example Purtov 1994 and Wishak 1995-2006). The spread of the Wishak measurements is puzzling.

Comment from requester:
A new dispersive coupled-channel optical model potential (5 keV - 200 MeV) derived using the requested data (plus the existing database above 200 keV) will have a direct impact on future evaluations of neutron induced reactions on gold.

Review comment:
While considerable data exist for the 5-200 keV total cross section, there is considerable scatter in these data. The measurement range is well suited for time-of-flight facilities and may also be accessed with quasi-monoenergetic beams using the Li(p,n) neutron source reactions. For a transmission measurement optimal conditions are obtained with a transmission factor close to 0.5, which implies that getting a sample might be costly, but purity and chemical issues should not be concerns. A measurement which overlaps with the region of the Au capture standard (200 keV to 2.5 MeV) would be of interest to allow a consistency check.

Entry Status:
Completed (as of SG-C review of May 2018) - The JEFF-3.2 evaluation [Sirakov:2013] based on new JRC-Geel measurements [Sirakov:2014;Massimi:2014] is significantly below the target accuracy. The evaluation has been validated against the Grenoble LSDS integral experiment [Zerovnik:2013].

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

R. Hannaske, et al., Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source, EPJA 49 (2013) 137, EXFOR 23199
I. Sirakov, et al., Results of total cross section measurements for 197Au in the neutron energy region from 4 to 108 keV at GELINA, EPJA 49 (2014) 144, EXFOR 23222
C. Massimi et al., Neutron capture cross section measurements for 197Au from 3.5 to 84 keV at GELINA, EPJA 50 (2014) 124, EXFOR 23253

Theory/Evaluation

A.B. Smith, Neutron Scattering from the Standard 197Au, ANL/NDM-161, 2005
I. Sirakov et al., Evaluation of neutron induced reaction cross sections on gold, Report JRC 78690, EUR 25803, 2013
B. Becker, et al., Evaluation of the Covariance Matrix of Estimated Resonance Parameters, NDS 118 (2014) 381
A.D. Carlson et al., Evaluation of the Neutron Data Standards, NDS 148 (2018) 143

Validation

G. Zerovnik et al., Use of the Grenoble lead slowing-down experiment for cross section validation, IAEA Consultants Meeting, 8-10 October 2013

Additional file attached:AU197_NTOT_RECENT.ps
Additional file attached:AU197_WISHAK.ps

Request ID 91 Type of the request Special Purpose Quantity

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

79-AU-197 (n,xn) x=3-5 SIG 20MeV/Thr.-100 MeV 5-10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Dosimetry High-energy 06-OCT-17 06-OCT-17

Requester: Dr Stanislav SIMAKOV at KIT, GER
Email: intersurfen@gmail.com

Project (context): IRDFF project

Impact:
The International Reactor Dosimetry and Fusion File (IRDFF) aims at providing evaluated neutron dosimetry reactions validated for all applications related to fission reactors and fusion technology development [IAEA2017].

Accuracy:
5%-10%

Justification document:
Accurate cross sections as well as spectrum-averaged cross sections (SACS) in relevant and well-characterized neutron fields are essential for improvement and validation of the evaluated data [Simakov2017].

Comment from requester:
The IRDFF project strives to evaluate, and eventually add to the library, high-threshold reactions with cross section plateaus located between 15/20 MeV and 100/150 MeV to meet the requirements of the accelerator-driven high-energy neutron sources. Note that it is important to know the cross section tail up to 100/150 MeV in order to allow the deconvolution of high-energy quasi-monoenergetic neutron source spectra.

References

[IAEA2017] IAEA CRP on Testing and Improving the International Reactor Dosimetry and Fusion File (IRDFF),
http://www-nds.iaea.org/IRDFFtest/.
[Simakov2017] S. Simakov, et al., “Proposals for new measurements for IRDFF community and HPRL”, September 2017.

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

M. Majerle, P. Bem, et al., Au, Bi, Co and Nb cross-section measured by quasimonoenergetic neutrons from p+7Li reaction in the energy range of 18-36 MeV, Nuclear Physics A 953 (2016) 139
P. Chudoba, et al., Activation Measurements of Cross Sections for Ground and Isomeric States Production in Neutron Threshold Reactions on Y and Au, Nuclear Science and Engineering 191 (2018) 150-160
M. Schulc, et al., Constraining high energy tail of ²³⁵U(n_th,f) prompt fission neutron spectrum, Applied Radiation and Isotopes 166 (2020) 109313
M. Schulc, et al., Measurement of very high threshold reactions using 252Cf source, Applied Radiation and Isotopes 166 (2020) 109355

Additional file attached:Simakov2017.pdf
Additional file attached:Au(n,xn)_HighEnDos.pdf

Request ID	91		Type of the request	Special Purpose Quantity
Target	Reaction and process	Incident Energy	Secondary energy or angle	Target uncertainty	Covariance
79-AU-197	(n,xn) x=3-5 SIG	20MeV/Thr.-100 MeV		5-10	Y
Field	Subfield	Date Request created	Date Request accepted	Ongoing action
Dosimetry	High-energy	06-OCT-17	06-OCT-17