nSoft 10 m SANS Detector Upgrade

The 10 m SANS is the flagship instrument of the nSoft consortium, enabling measurement technique development and rapid access for industrial members.  The instrument previously relied on an obsolete monolithic multiwire proportional counter detector.  A new area detector has recently been installed, comprised of an array of linear position sensitive proportional counter tubes grouped in “8-pack” modules.  Fourteen such modules are laid out to form an active area of 1.1 m². A major advantage of this modular scheme is that individual 8-packs can replaced or rearranged on the frame without removing the entire detector from service.  The sensitivity is 75% for 5 Å (3.27 meV) neutrons, and the spatial resolution is 8 mm x 6 mm. The event discrimination and position encoding electronics are located on each module so the count rate over the entire detector is specified to exceed two million counts per second.  Additionally, the new detector array is capable of time-stamping neutron events with nanosecond precision using the Precision Time Protocol (IEEE-1588).