Measurement of the MACS of at kT=30keV as a test of a method for Maxwellian neutron spectra generation

Praena, J.; Mastinu, P.; Pignatari, M.; Quesada, J.; Garcı́a-López, J.; Lozano, M.; Dzysiuk, N.; Capote, R.; Martín-Hernández, Guido

doi:10.1016/j.nima.2013.05.151

Cited by 20 publications

(6 citation statements)

References 19 publications

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“…For the K n calculation, a Fortran code [9] was used to generate the energy-angle distribution of the neutrons for the 7 Li(p,n) reaction, as the input for MCNPX. The code and the MCNPX simulations for the proton energy (1912 keV) involved in this experiment were tested with experimental data, see details in [10]. For K f calculation, the angle-energy distribution of the neutron spectrum (θ,E) and the energy dependence of the 197 Au(n,) cross section must be taken into account.…”

Section: Pos(nic Xiii)102mentioning

confidence: 99%

MEASUREMENT OF THE 197Au(n,gamma) STELLAR CROSS SECTION BY ACTIVATION

Bonilla¹

2015

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII)

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The Maxwellian-averaged cross-section (MACS) of 197 Au(n,) at kT=30 keV is used in Nuclear Astrophysics as a reference for activation measurements relevant to the s-process. The traditionally adopted value, (582±9) mb, corresponds to an accurate activation measurement carried out by Ratynski & Käppeler in 1988. Recently, new measurements with the time-offlight technique have reported values about 5 % higher than Ratynski&Käppeler. Moreover, the evaluations of different data base provide values from 613-618 mb. In our work we have measured the MACS of 197 Au(n,) at kT=30 keV by activation, at 3 MV Tandem Pelletron accelerator at CNA (Seville). We have found a value equal to (626±25) mb. We describe the experiment and we discuss the analysis, including MCNPX simulations and a correction proposed for flat samples, and a comparison with previous and recent measurements.

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Section: Pos(nic Xiii)102mentioning

confidence: 99%

MEASUREMENT OF THE 197Au(n,gamma) STELLAR CROSS SECTION BY ACTIVATION

Bonilla¹

2015

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII)

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“…HISPANoS, from Hispalis Neutron Source ( ), is the first accelerator-based neutron source (pulsed and continuous wave) in Spain located at the 3 MV tandem accelerator at the National Accelerator Centre (CNA, Seville) [ 9 , 10 ]. At HISPANoS, fast, epithermal, and thermal neutrons can be delivered through different nuclear reactions [ 2 , 11 , 12 ]. In the case of the epithermal beams of interest in this work, the proton beam and beam-shaping assembly (BSA) configurations from Fantidis et al [ 13 ] have been considered: a proton beam of 2.5 MeV, in our case, with a current of 10 µA would hit a water-cooled thick lithium target, producing, in the absence of the BSA, ~3·10 7 n/cm 2 /s at 10 cm.…”

Section: Methodsmentioning

confidence: 99%

Quantification of Boron Compound Concentration for BNCT Using Positron Emission Tomography

Balcerzyk

Miguel

Guerrero

et al. 2020

Cells

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Background: Boron neutron capture therapy requires a 2 mM 10B concentration in the tumor. The well-known BNCT patient treatment method using boronophenylalanine (BPA) as a boron-carrying agent utilizes [18F]fluoroBPA ([18F]FBPA) as an agent to qualify for treatment. Precisely, [18F]FBPA must have at least a 3:1 tumor to background tissue ratio to qualify the patient for BNCT treatment. Normal, hyperplasia, and cancer thyroids capture iodine and several other large ions, including BF4−, through a sodium-iodine symporter (NIS) expressed on the cell surface in normal conditions. In cancer, NIS is also expressed within the thyroid cell and is not functional. Methods: To visualize the thyroids and NIS, we have used a [18F]NaBF4 positron emission tomography (PET) tracer. It was injected into the tail veins of rats. The [18F]NaBF4 PET tracer was produced from NaBF4 by the isotopic exchange of natural 19F with radioactive 18F. Rats were subject to hyperplasia and tumor-inducing treatment. The NIS in thyroids was visualized by immunofluorescence staining. The boron concentration was calculated from Standard Uptake Values (SUV) in the PET/CT images and from the production data. Results: 41 MBq, 0.64 pmol of [18F]NaBF4 PET tracer that contained 0.351 mM, 53 nmol of NaBF4 was injected into the tail vein. After 17 min, the peak activity in the thyroid reached 2.3 MBq/mL (9 SUVmax). The natB concentration in the thyroid with hyperplasia reached 381 nM. Conclusions: Such an incorporation would require an additional 110 mg/kg dose of [10B]NaBF4 to reach the necessary 2 mM 10B concentration in the tumor. For future BNCT treatments of thyroid cancer, contrary to the 131I used now, there is no post-treatment radioactive decay, the patient can be immediately discharged from hospital, and there is no six-month moratorium for pregnancy. This method can be used for BNCT treatment compounds of the type R-BFn, where 1 <= n <= 3, labeled with 18F relatively easily, as in our example. A patient may undergo injection of a mixture of nonradioactive R-BFn to reach the necessary 10B concentration for BNCT treatment in the tumor together, with [18F]R-BFn for boron mapping.

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“… Ta is produced by two minor branchings in the s -process along the stable hafnium isotopes which is discussed by Kappeler et al 5 and Malatji et al 6 . Ta is produced by the s-process, its ( ) cross sections and MACS at 30 keV are of great significance in nuclear astrophysics for understanding the reaction path of the s -process 7 , 8 . However, according to the EXFOR library, high-precision, continuous measurements of capture cross sections in the resolved resonance region are not sufficient.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the $$ ^{181} $$Ta($$n,\gamma $$) cross sections up to stellar s-process temperatures at the CSNS Back-n

An¹,

Qiu²,

Jiang³

et al. 2023

Sci Rep

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The neutron capture cross section of $$ ^{181} $$ 181 Ta is relevant to s-process of nuclear astrophysics, extraterrestrial samples analysis in planetary geology and new generation nuclear energy system design. The $$^{181}$$ 181 Ta($$n,\gamma $$ n , γ ) cross section had been measured between 1 eV and 800 keV at the back-streaming white neutron facility (Back-n) of China spallation neutron source(CSNS) using the time-of-flight (TOF) technique and $$\hbox {C}_{6}\,\hbox {D}_{6}$$ C 6 D 6 liquid scintillator detectors. The experimental results are compared with the data of several evaluated libraries and previous experiments in the resolved and unresolved resonance region. Resonance parameters are extracted using the R-Matrix code SAMMY in the 1–700 eV region. The astrophysical Maxwell average cross section(MACS) from kT = 5 to 100 keV is calculated over a sufficiently wide range of neutron energies. For the characteristic thermal energy of an astrophysical site, at kT = 30keV the MACS value of $$^{181}$$ 181 Ta is 834 ± 75 mb, which shows an obvious discrepancy with the Karlsruhe Astrophysical Database of Nucleosynthesis in Stars (KADoNiS) recommended value 766 ± 15 mb. The new measurements strongly constrain the MACS of $$^{181}$$ 181 Ta($$n,\gamma $$ n , γ ) reaction in the stellar s-process temperatures.

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Measurement of the MACS of at kT=30keV as a test of a method for Maxwellian neutron spectra generation

Cited by 20 publications

References 19 publications

MEASUREMENT OF THE 197Au(n,gamma) STELLAR CROSS SECTION BY ACTIVATION

MEASUREMENT OF THE 197Au(n,gamma) STELLAR CROSS SECTION BY ACTIVATION

Quantification of Boron Compound Concentration for BNCT Using Positron Emission Tomography

Measurement of the $$ ^{181} $$Ta($$n,\gamma $$) cross sections up to stellar s-process temperatures at the CSNS Back-n

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