Neutron-upscattering enhancement of the triple-alpha process

BISHOP, J., PARKER, C.E., ROGACHEV, G.V., AHN, S., KOSHCHIY, E., BRANDENBURG, K., BRUNE, C.R., CHARITY, R.J., DERKIN, J., DRONCHI, N., HAMAD, G., JONES-ALBERTY, Y., KOKALOVA, Tz., MASSEY, T.N., MEISEL, Z., OHSTROM, E.V., PANERU, S.N., POLLACCO, E.C., SAXENA, M., SINGH, N., SMITH, Robin, SOBOTKA, L.G., SOLTESZ, D., SUBEDI, S.K., VOINOV, A.V., WARREN, J. and WHELDON, C. (2022). Neutron-upscattering enhancement of the triple-alpha process. Nature Communications, 13: 2151.

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The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of 12C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO2 gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers).

Item Type: Article
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SWORD Depositor: Symplectic Elements
Depositing User: Symplectic Elements
Date Deposited: 25 Apr 2022 14:24
Last Modified: 09 May 2022 11:21

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