München 2009 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 75: Experimentelle Methoden 1
T 75.2: Gruppenbericht
Mittwoch, 11. März 2009, 17:05–17:25, A022
PENeLOPE, progress report on a new magnetic UCN trap for a precise neutron lifetime measurement. — •Stefan Materne, Igor Altarev, Beatrice Franke, Erwin Gutsmiedl, Joachim Hartmann, Axel Müller, Stephan Paul, Rüdiger Picker, Rainer Stoepler, and Christian Tietze — TU München, Physik-Department
The neutron lifetime τn is an important parameter for cosmological models and moreover helps to test the standard model of particle physics. However, recent measurements of the neutron lifetime disagree by roughly 6σ and the situation needs to be clarified.
Hence, at the Technische Universität München a new storage experiment with ultra-cold neutrons (UCN) is constructed. In contrast to material storage experiments so far, the UCN will be trapped by a magnetic multipole field created with superconducting coils. Vertically, the UCN will be bound by gravitation, which makes the extraction and detection of the decay protons possible and allows a direct measurement of the neutron decay rate. The precision of 0.1 s and the accuracy aimed at demands a large storage time and good knowledge of systematic errors, which could result e.g. from neutron spin flip and high-energy UCN. The big storage volume, more than 700 l, and the expected large UCN density at the next generation UCN sources give more than 107 neutrons per cycle and meet statistical demands. The talk will cover the design of the experiment, a discussion of the expected sytematical effects as well as the results of pre-experiments.
Supported by MLL, DFG and excellence initiative EXC 153.