Study of Neutron Interaction with Copper

Data from the Si detectors of n_TOF's EAR1 was analysed in the context on the on-going Cu-63 campaign in order to monitor and assess data quality and uniformity. By only considering neutron energies below 300 keV, a linear relationship was obtained between the pulse intensity, $y$, and tritium counts, $x$: $y= \left[ (3.84 \pm 0.01)x +(2.9 \pm 0.1) \right] \times 10^{11}$. Similar trends were found for all run types (n+Cu, n+Au, n+Pb, n+Empty). By performing the same analysis averaged over the whole run, the ratio of the two above quantities was found to be constant over runs 119176-119315, with no outliers. In fact it deviated by less than 1% for both parasitic and dedicated bunches. The gain of each Si detector was seen to be similar for both bunch types. This quantity did not vary by more than 0.5% over the campaign. It varied most for SILI 2 and least for SILI 3. The resolution varied more between parasitic and dedicated bunches, but by no more than 1%. For all of the detectors this quantity remained between 6.5-7.5% throughout the campaign. SILI 3 had the worse, against SILI 4 with the best. Finally, Cd and S filters were used. Characteristic resonances of these elements were used to confirm the in-beam presence of these filters during the runs.