D. Makowiecki

A large, high performance, curved 2D position-sensitive neutron detector ☆

Abstract A new position-sensitive neutron detector has been designed and constructed for a protein crystallography station at LANLs pulsed neutron source. This station will be one of the most advanced instruments at a major neutron user facility for protein crystallography, fiber and membrane diffraction. The detector, based on neutron absorption in 3He, has a large sensitive area of 3000 cm 2 , angular coverage of 120°, timing resolution of 1 μs , rate capability in excess of 10 6 s −1 , position resolution of about 1.5 mm FWHM, and efficiency >50% for neutrons of interest in the range 1– 10 A . Features that are key to these remarkable specifications are the utilization of eight independently operating segments within a single gas volume, fabrication of the detector vessel and internal segments with a radius of curvature of about 70 cm , optimized position readout based on charge division and signal shaping with gated baseline restoration, and engineering design with high-strength aluminum alloy.

A GEM based TPC for the LEGS experiment

A compact time projection chamber (TPC) has been constructed for the LEGS (Laser Electron Gamma Source) experiment at BNL. The TPC uses double GEMs as the amplification stage. Position encoding is achieved through charge division using zigzag shaped anode pads. The TPC has a 35 cm diameter active area and a 50 cm long drift depth. It has more than 7000 channels of readout electronics in the form of custom designed ASICs. A novel peak sensing circuit is used to measure simultaneously the amplitude and timing of the signal peak from an anode pad. Test results from a shorter prototype version of the TPC as well as the construction of the final detector are discussed.

Readout electronics for the MicroBooNE LAr TPC, with CMOS front end at 89K

MicroBooNE experiment will use a ~ 100 ton Liquid Argon (LAr) Time Projection Chamber (TPC) detector, presently under construction, to observe interactions of neutrinos from the on-axis Booster Neutrino Beam and off-axis NuMI Beam at Fermi National Accelerator Laboratory. The experiment will address the low energy excess observed by the MiniBooNE experiment, measure low energy neutrino cross sections, and serve as the necessary next step in a phased program towards massive Liquid Argon TPC detectors. An overview of the front end readout architecture of the MicroBooNE experiment will be presented. The design, prototypes and the production electronics system, comprised of cold CMOS electronics, warm interface electronics and TPC digitizing electronics will be described in some detail. The results of extensive tests on the noise versus temperature and of the uniformity of response will be presented.

Front-end ASIC for a liquid argon TPC

We introduce a front-end application specific integrated circuit (ASIC) for a wire based Time-Projection-Chamber (TPC) operating in liquid Argon (LAr). The LAr TPC will be used for long baseline neutrino oscillation experiments. The ASIC must provide low-noise readout of the signals induced on the TPC wires, digitization of those signals at 2 MS/s, compression, buffering and multiplexing. A resolution better than 1000 rms electrons at 200 pF input capacitance for an input range of 300 fC is required, along with low power and operation in LAr (at 87 K). We present the characterization of a commercial technology for operation in cryogenic environment and the first experimental results on the analog front-end. The results demonstrate that CMOS transistors have lower noise and much improved dc characteristics at LAr temperature. Finally, we introduce the concept of “1/f equivalent” to model the low-frequency component of the noise spectral density, for use in the input MOSFET optimization.