Dresden 2013 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 45: Instrumentation
HK 45.8: Talk
Tuesday, March 5, 2013, 18:45–19:00, HSZ-405
Direct detection of low energy protons using large-area avalanche photodiodes (LAAPDs) — •Thomas Pöschl — Technische Universität München, Physik Department, E18
In the last couple of years the average of the measured neutron lifetime has decreased steadily. Discrepancies by more than 6σ from the world average value demand new precise measurements of this quantity. One promising experiment is PENeLOPE, which is developed at the Physics Department of Technische Universität München. This magnetic-bottle experiment is not only based on counting the surviving neutrons, but also on detecting the protons from the neutron decay in order to obtain better precision. Although the protons are accelerated by an electric field of about 30 keV, the detection is challenging because of their little penetration depth of only a few hundred nanometers in most materials.
In our work we investigate the response of a large-area avalanche photodiode (LAAPD) to protons, H2+ and H3+ ions with kinetic energies up to 30 keV. We already achieved to detect protons down to 10 keV with a good resolution of 2.8 keV (FWHM) at room temperature. For this measurements we used the linear accelerator PAFF which has been built as a test facility for detector characterization.
This work is supported by the Excellence Cluster “Origin and Structure of the Universe”, Deutsche Forschungsgemeinschaft and the Maier-Leibnitz-Laboratorium Garching.