Measurements of the ²⁷Al(α,<i>n</i>) Thick Target Yield near Threshold

We present results from direct measurements of the $^{27}{\rm Al}(\alpha,n)$ thick target yield laboratory incident energies $E_{\alpha}\approx$ 3$-$5~MeV, performed with $^{3}$HeBF$_{3}$ Giant Barrel (HeBGB) neutron detector at Edwards Accelerator Laboratory. Our have a small energy cadence in order to address discrepancies and sparseness thick-target data sets existing for this region. find general agreement sets, including yields derived cross section data, while resolving discrepancy between $E_{\alpha}\approx4-5$~MeV. However, $E_{\alpha}<3.5$~MeV, our are substantially lower than previous somewhat larger calculated data. complete energy-range needed estimates contribution neutrino dark matter backgrounds result increased viability as plasma diagnostic tool fusion facilities such National Ignition Facility.