Ponente
Descripción
Neutrons from ($\alpha$,n) reactions are essential for astrophysics, dark matter experiments, and nuclear material interrogation, yet available cross-section and yield data are limited and often uncertain [1]. To improve this situation, the Spanish nuclear physics community has established the MANY Collaboration (Measurement of Alpha Neutron Yields).
At CNA [2], the 3 MV tandem accelerator provides alpha beams up to 9 MeV, either in continuous mode (maximum 500 nA with the ALPHATROSS source [3]) for activation and neutron counting, or in pulsed mode (2% duty cycle) for time-of-flight [4].
Recent and planned upgrades at the neutron beam line CNA-HiSPANoS aim to expand its capabilities for ($\alpha$,n) measurements: a new buncher system has been installed, improving the structure of the pulsed beam and allowing for more precise time-of-flight measurements, a more intense He$^{++}$ ion source (NEC-TORVIS [5]) has been acquired and is expected to increase the beam intensity by an order of magnitude, and the purchase of a new array of fast neutron detectors (EJ-309) is underway in order to improve detection efficiency and angular coverage.
In parallel, an innovative technique for beam current determination in non-conductive materials and/or some gaseous elements, using aluminum alloys. By employing an AlN alloy target, the ($\alpha$,n) reaction on $^{14}$N, in principle a gaseous target that would pose a serious difficulty, is measured with respect to the well-known $^{27}$Al($\alpha$,n)$^{30}$P reaction, enabling a reliable Thick Target Yield (TTY) measurement by means of activation.
This contribution will include the definitive results for the measurement of the $^{27}$Al($\alpha$,n)$^{30}$P reaction by activation as well as preliminary results for the $^{14}$N($\alpha$,n)$^{17}$F measurements and the commissioning of the new bunching system for $\alpha$ beams. Then, planned upgrades of the ion source and the neutron detectors will be presented.
[1] D. Cano-Ott et al., Review of Neutron Yield from ($\alpha$, n) Reactions: Data, Methods, and Prospects, [https://arxiv.org/abs/2405.07952]
[2] J. Gómez-Camacho, J. García López, C, Guerrero et al. Research facilities and highlights at the Centro Nacional de Aceleradores (CNA), Eur. Phys. J. Plus 136, 273 (2021). https://doi.org/10.1140/epjp/s13360-021-01253-x
[3] NEC Alphatross Source RF-Charge Exchange Ion Source https://www.pelletron.com/
[4] M.A. Millán-Callado et al., Continuous and pulsed fast neutron beams at the CNA HiSPANoS facility. Rad. Phys. & Chem. 217 (2024) 111464
[5] NEC Toroidal Volume Ion Source https://www.pelletron.com/
Abstract
Neutrons from (a,n) reactions are essential for astrophysics, dark matter experiments, and nuclear material interrogation, yet available cross-section and yield data are limited and often uncertain [1]. To improve this situation, the Spanish nuclear physics community has established the MANY Collaboration (Measurement of Alpha Neutron Yields).
At CNA [2], the 3 MV tandem accelerator provides alpha beams up to 9 MeV, either in continuous mode (maximum 500 nA with the ALPHATROSS source [3]) for activation and neutron counting, or in pulsed mode (2% duty cycle) for time-of-flight [4].
Recent and planned upgrades at the neutron beam line CNA-HiSPANoS aim to expand its capabilities for (a,n) measurements: a new buncher system has been installed, improving the structure of the pulsed beam and allowing for more precise time-of-flight measurements, a more intense He++ ion source (NEC-TORVIS [5]) has been acquired and is expected to increase the beam intensity by an order of magnitude, and the purchase of a new array of fast neutron detectors (EJ-309) is underway in order to improve detection efficiency and angular coverage.
In parallel, an innovative technique for beam current determination in non-conductive materials and/or some gaseous elements, using aluminum alloys. By employing an AlN alloy target, the (a,n) reaction on 14N, in principle a gaseous target that would pose a serious difficulty, is measured with respect to the well-known 27Al(a,n)30P reaction, enabling a reliable Thick Target Yield (TTY) measurement by means of activation.
This contribution will include the definitive results for the measurement of the 27Al(a,n)30P reaction by activation as well as preliminary results for the 14N(a,n)17F measurements and the commissioning of the new bunching system for alpha beams. Then, planned upgrades of the ion source and the neutron detectors will be presented.
[1] D. Cano-Ott et al., Review of Neutron Yield from (α, n) Reactions: Data, Methods, and Prospects, [https://arxiv.org/abs/2405.07952]
[2] J. Gómez-Camacho, J. García López, C, Guerrero et al. Research facilities and highlights at the Centro Nacional de Aceleradores (CNA), Eur. Phys. J. Plus 136, 273 (2021). https://doi.org/10.1140/epjp/s13360-021-01253-x
[3] NEC Alphatross Source RF-Charge Exchange Ion Source https://www.pelletron.com/
[4] M.A. Millán-Callado et al., Continuous and pulsed fast neutron beams at the CNA HiSPANoS facility. Rad. Phys. & Chem. 217 (2024) 111464
[5] NEC Toroidal Volume Ion Source https://www.pelletron.com/
