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HK: Fachverband Physik der Hadronen und Kerne

HK 78: Fundamentale Symmetrien

HK 78.5: Vortrag

Donnerstag, 7. März 2013, 18:15–18:30, HSZ-401

aSPECT, prepared for a new physics run — •Alexander Wunderle and Marcus Beck — Institut für Physik, Johannes Gutenberg-Universität Mainz

The aSPECT retardation spectrometer measures the electron antineutrino angular correlation coefficient a in free neutron β-decay with high precision. This measurement can be used to determine the ratio of g_A/g_V of the weak coupling constants, as well as to search for physics beyond the Standard Model. Currently a is known with a precision of Δ a/a ≈ 4 % (PDG), whereas aSPECT aims for a precision of Δ a/a ≈ 0.3 %.

Since the last physics run of aSPECT at the Institut Laue-Langevin (ILL) in 2011 several significant improvements have been implemented. Namely the surfaces of our electrodes have been smoothed and therefore their field emission could be reduced. This and the renewal of several electrodes reduced runaway discharges in the spectrometer considerably. In the same step the uncertainty of the transmission-function due to workfunction fluctuations of the main electrode could be lowered considerably.

Since 2012 aSPECT has been operated at a separate test zone at the ILL, where we could investigate and determine the background level in our spectrometer in detail (see talk of Romain Maisonobe).

With all the improvements presented in this talk, we will determine a in 2013 with a yet unknown precision.