Russina, M.; Guenther, G.; Grzimek, V.; Gainov, R.; Schlegel, M.; Drescher, L.; Kaulich, T.; Graf, W.; Urban, B.; Daske, A.; Grotjahn, K.; Hellhammer, R.; Buchert, G.; Kutz, H.; Rossa, L.; Sauer, O.-P.; Fromme, M.; Wallacher, D.; Kiefer, K.; Klemke, B.; Grimm, N.; Gerischer, S.; Tsapatsaris, N.; Rolfs, K.: Upgrade project NEAT'2016 at Helmholtz Zentrum Berlin - What can be done on the medium power neutron source. Physica B 551 (2018), p. 506-511
The neutron time-of-flight spectrometer NEAT has a long history of successful applications and is best suited to probe dynamic phenomena directly in the large time domain 10^-14 - 10^-10 s and on the length scale ranging from 0.05 to up to about 5 nm. To address user community needs for more powerful instrumental capabilities, a concept of the full upgrade of NEAT has been proposed. The upgrade started in 2010 after a rigorous internal and external selection process and resulted in 300-fold neutron count rate increase compared to NEAT'1995. Combined with new instrumental and sample environmental capabilities the upgrade allows NEAT to maintain itself at the best world class level and provide an outstanding experimental tool for a broad range of scientific applications. The advanced features of the new instrument include an integrated guide-chopper system that delivers neutrons with flexible beam properties: either highly homogeneous beam with low divergence suitable for single crystals studies or "hot-spot" neutron distribution serving best small samples. Substantial increase of the detector angle coverage is achieved by using 416 3He position sensitive detectors. Placed at 3 m from the sample, the detectors cover 20 m^2 area and are equipped with modern electronics and DAQ using event recording techniques. The installation of hardware has been completed in June 2016 and on January 23, 2017 NEAT has welcomed its first regular users who took advantage of the high counting rate, broad available range of incoming neutron wavelengths and high flexibility of NEAT. Here we present details of NEAT upgrade, measured instrument characteristics and show first experimental results.