Speaker
Dr
Deon Marais
(The South African Nuclear Energy Corporation (Necsa) SOC Limited)
Description
The current detector system of Necsa’s Powder Instrument for Transition in Structure Investigations (PITSI) neutron diffractometer consists of 15 vertically stacked 609.6 mm x 25.4 mm Reuter-Stokes He3 gas-filled position sensitive tube detectors. This assembly results in a pseudo area detector with an active area of ~610 x 380 mm2. At a sample-to-detector distance of 1.6 m, the detector spans a 2θ angle of a mere 21°, requiring the detector to be step-scanned to 6 positions in order to cover a range of 10° ≤ 2θ ≤ 120°. This significantly influences measurement time.
A project is currently under way to increase the active area of the detector by adding an additional 33 tubes. The resulting detector assembly will consist of three banks each containing 16 tubes, separated by a dead-space of 18.5° at 1.6 m. This configuration requires a step-scan of only 2 positions to cover the complete 2θ range, effectively increasing the instrument acquisition speed by a factor greater than 3. The sample to detector distance can be varied from 1.6 m to 1.2 m providing the ability to reduce the measurement time even more with a trade-off in angular resolution.
The current USB-communication based electronics (from Instrumentation Associates) will also be replaced by an Ethernet based Mesytec system to increase stability and reduce the amount of cabling needed.
| Formal Invitation Letter Required | Yes |
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Primary author
Dr
Deon Marais
(The South African Nuclear Energy Corporation (Necsa) SOC Limited)
Co-authors
Dr
Andrew Venter
(The South African Nuclear Energy Corporation (Necsa) SOC Limited)
Mr
Christo Raaths
(The South African Nuclear Energy Corporation (Necsa) SOC Limited)
Mr
Mark Lesha
(Australian Nuclear Science and Technology Organisation (ANSTO))
Mr
Rudolph Van Heerden
(The South African Nuclear Energy Corporation (Necsa) SOC Limited)
