Detector Laboratory

Staff of the detector lab support users during their experiments and measurements at the BER II neutron source should any problems arise with the detectors. It is our ultimate ambition to guarantee technically faultless operation to allow the efficient use of precious beam time. Our responsibilities include primary detectors (monitors, delay line detectors, and counter tube arrays), amplifier- and discriminator electronics, as well as data acquisition interfaces. Last but not least we provide software support for DeLiDAQ und Q-MesyDAQ.

Since 2009 there has been a dramatic global shortage of the widely used neutron converter gas helium-3. This has increased pressure to develop new detector technologies. To facilitate this, the International Collaboration for the Development of Neutron Detectors (ICND) was formed by the leading neutron laboratories, including FRM-II, FZJ, ILL, ISIS, SNS, JPARC and HZB. The detector group of the department G-A1 takes a very active role in this effort, coordinating the development of detectors using boron-trifluoride gas. Two other alternatives which the collaboration is investigating are: (i) scintillation detectors (coordinated by ISIS), and (ii) detectors with multi-layers boron-10 detectors (coordinated by ILL). The urgency of finding an alternative to helium-3 is underlined by the development of large area detector arrays covering dozens of square meters and requiring the replacement of several thousand liters of helium-3 (such as the time-of-flight spectrometer NEAT).

With respect to detector development, the realisation of a micro-strip gas chamber (MSGC) with gadolinium-157 as a neutron converter is another main focus of the detector lab. This detector is characterised by a very high count rate capability (~1E7 n/s) and a very good 2-dimensional position resolution (<0.5 mm). The development work is carried out in the framework of the Design-Update of the European Spallation Source (ESS) and is funded by the Federal Ministry of Research BMBF.

Last but not least the members of the detector lab advise the instrument responsibles on the choice of detectors suitable for the conceptual design of new instruments. Detailed simulations guarantee in advance that the suggested detector concept meets the scientific demands. As a matter of course we also follow the mechanical construction and production of the detector assembly. The detector system is then setup and tested in the lab. Finally, after the detector system has been assembled and commissioned, it is handed over to the instrument responsible. Examples of recent developments are four detector panels each equipped with 48 linear position-sensitive detectors (LPDs) for the EXED experiment and the new SANS detector with 112 LPDs.