The Neutron Detector Service (SDN) of the ILL has two principle objectives:
- to ensure that the detectors of the Institute and their electronics function as desired
- to develop new detectors which can be tailored to meet an instrument's individual requirements:
the demand for detectors has increased dramatically during the last years, not only as regards performance, but also production capability.
MSGC, MWPC and Multi-tube detectors cover most of the experimental conditions associated with intense neutron sources:
- MSGC (Micro-Strip Proportional Counter) are now considered to be fully commissioned for neutron instrumentation, but their main drawback is their limited size (about 25 cm x 25 cm per unit). They are used on the ILL's D4C and D20 powder diffractometers.
- MWPC (Multi-Wire Proportional Counter) are best suited when larger 2-dimensional detectors are needed without dead space. In 2002 we started the development of a 2D curved vessel MWPC for D19 with an angular coverage of 120° horizontally and 30° vertically. This detector has been operational since 2005.
- The Multitube (patent pending) is made of identical tubes brazed side by side on both ends to a common pressure vessel. The position along the tubes is measured by charge division. Prototypes with different sizes of tubes, from 3000 mm long, 25 mm diameter, to 250 mm long, 4.5 mm diameter, have been successfully tested as part of the modernisation of several ILL instruments. This new gaseous detector has been developed to respond to the demand for cost-effective, very large-area, fast detectors. The IN5 chopper spectrometer will be equipped in 2008 with 12 Multitube modules, covering a total sensitive area of 30 M2.
- The SDN has participated in the MILAND international project (FP6 programme), which aims to develop a 2D fast detector with a 32 cm x 32 cm sensitive area, and a 1 mm position resolution.
Head of service: Bruno Guérard