Expansion of the detector bank of the Necsa neutron powder diffractometer

Abstract

The neutron detector of Necsa's "Powder Instrument for Transition in Structure Investigations" (PITSI) diffractometer is a pseudo area configuration that has an active area of ∼ 610 × 375 mm 2 that is established by 15 vertically stacked 3 He gas-filled linear position sensitive tube detectors. In its standard geometry the sample-to-detector distance is 1.6 m that gives a detector sustention angle of 2θ = 21 •. A full diffraction pattern over the range 10 • 2θ 115 • is covered in six discrete steps. This process may be very time consuming for weak scattering materials. To improve the instrument performance, the active area of the detector bank is being increased to 48 tubes comprising three banks each with 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 of interest, effectively increasing the instrument acquisition speed by a factor greater than 3. As an added flexibility the overall data acquisition time can be further reduced by decreasing the sample to detector distance to 1.2 m that increases the intensity per pixel at the expense of the instrument's angular resolution. In this report the conversion of the current USB-communication based system to an Ethernet based system to reduce the hardware footprint and complexity, as well as the amount of cabling needed is reported. The optimisation of the operating parameters of the new detector electronics is also discussed.

Open science and Big Data in South Africa

“…The MPR project is now in the design phase with construction planned to start in 2025. A new Neutron Beam Line Center is being planned and a new software stack comprising the instrument control system, user interface and data reduction and analysis components will need to be built (Marais, 2022 ). In addition, the data management processes will need to support the generation of FAIR data.…”

“…These management activities range from defining and maintaining a data policy, enabling data discovery and access, up to data archiving and preservation. The new Neutron Beam Line Center at the planned MPR facility is planning the development of a whole new software stack for neutron science (Marais, 2022 ). With the South Africa draft policy on Open Science this must now require the creation of FAIR datasets.…”

8th Design and Engineering of Neutron Instruments Meeting in North Bethesda Maryland, USA 17–19 September 2019

“…Motivated by the knowledge that conceptual design through installation and test of similar neutronic instruments in isolation was less efficient and effective than collaboration, DENIM was first conceived of and hosted in 2012 by the Science & Technology Facilities Council -ISIS in Oxfordshire, United Kingdom [7]. Since then, DENIM has been coordinated by seven different neutron scattering facilities worldwide [2][3][4]6,8]. The ex- citing thing about DENIM is that it is organized by engineers for engineers, a unique community within neutron scattering science.…”