An nuclear magnetic resonancs (NMR) system has been developed for aSPECT in order to measure the magnetic field in the DV and AP regions at the required level. The figure of merit for the magnetic field at aSPECT is the magnetic field ratio in the DV and AP regions. It has to be known to 1e-4 or better in order to achieve the required precision for the determination of the beta-neutrino angular correlation coefficient.
A single aSPECT NMR-probe. The small glass tube contains a mixture of Acetone and Ethanol 50/50:
The mechanics for the two NMR probes for the DV and AP regions (including PhD student Ch. Schmidt, after the successful beam time 2013):