A medium resolution double crystal based small-angle neutron scattering instrument at Trombay

A double crystal-based moderate resolution Small-angle neutron scattering i nstrument has been built and commissioned at the guide laboratory of Dhruva reactor, Bhabha Atomic Research Centre, Trombay, India. The instrument con sists of a non-dispersive (1, -1) setting of 111 reflections of silicon sin gle crystals with the sample between the two crystals. The neutron waveleng th used is' 0.312 nm. At 65 MW of reactor power, the peak count rate of the blank rocking curve is about 55 counts per second at the detector position and the ratio of integrated signal to integrated noise is similar to 450 f or a typical experiment with sintered alumina. The accessible range of wave vector transfer q is found to be 0.003-0.173 nm(-1), which corresponds to a range of resolvable real-space dimension of 2000-40 nm, for these specime ns. The instrument is calibrated with respect to the high resolution ultra small-angle neutron scattering instrument S18 at the Institute Laue-Langevi n in Grenoble, France.