Richard Northrop

A Medium Sized Schwarzschild-Couder Cherenkov Telescope Design Proposed for the Cherenkov Telescope Array

K. Byrum, B.Humensky, W.Benbow, R.Cameron, S.Criswell, M.Errando, V.Guarino, P.Kaaret, D.Kieda, R.Mukherjee, D.Naumann, D.Nieto, R.Northrop, A.Okumura, E.Roache, J.Rousselle, S.Schlenstedt, R.Sternberger, V.Vassiliev, S.Wakely, H.Zhao for the *CTA Consortium 1 Argonne National Laboratory, 9700 S. Cass Ave. High Energy Physics Div., Lemont, IL 60439, 2 Columbia University, Physics Department, Department of Physics and Astronomy, Barnard College, New York, NY 10027, 3 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, 4 SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94025, 5 Fred Lawrence Whipple Observatory, 670 Mount Hopkins Rd, Amado, AZ 85645, 6 University of Iowa, Department of Physics and Astronomy, Iowa City, IA 52242, 7 University of Utah, Physics Department, Salt Lake City, UT 84112, 8 Deutsches Elektronen-Synchrotron(DESY), Platanenallee 6, 15738 Zeuthen, Germany, 9 University of Chicago, Enrico Fermi Institute, Chicago, IL 60637, 10 Solar-Terrestrial Environ. Lab, Nagoya Univ, Furo-cho, Chikusakku, Nagoya, Aichi 464-8601, Japan, 11 University of Leicester, Department of Physics and Astronomy, Leicester, LEI 7RH, UK, 12 Max-Planck-Institut fur Kernphysik, P.O. Box 103980, D 69029 Heidelberg, Germany, 13 University of California, Los Angeles, Department of Physics and Astronomy, LA, CA 90095 E-mail: byrum@anl.gov

Development of Large Area, Pico-second resolution Photo-Detectors and associated readout electronics

The Large Area Pico-second Photo-detectors described in this contribution incorporate a photo-cathode and a borosilicate glass capillary Micro-Channel Plate (MCP) pair functionalized by atomic layer deposition (ALD) of separate resistive and electron secondary emitters materials. They may be used for biomedical imaging purposes, a remarkable opportunity to apply technologies developed in HEP having the potential to make major advances in the medical world, in particular for Positron Emission Tomography (PET). If daisy-chained and coupled to fast transmission lines read at both ends, they could be implemented in very large dimensions. Initial testing with matched pairs of small glass capillary test has demonstrated gains of the order of 105 to 106. Compared to other fast imaging devices, these photo-detectors are expected to provide timing resolutions in the 10–100ps range, and two-dimension position in the sub-millimeter range. A 6-channel readout ASIC has been designed in 130nm CMOS technology and tested. As a result, fast analog sampling up to 17 GS/s has been obtained, the intrinsic analog bandwidth being presently under evaluation. The digitization in parallel of several cells in two microseconds allows getting off-chip digital data read at a maximum rate of 40 MHz. Digital Signal Processing of the sampled waveforms is expected achieving the timing and space resolutions obtained with digital oscilloscopes.

Large Area Micro-Channel Plates for LAPPD™

Manufacturing plans for “next generation” microchannel plates (MCPs) and the technical advantages enabled by this evolving technology are presented. The Large Area Picosecond Photodetector (LAPPD) is an MCP based photodetector, capable of imaging, with high spatial and temporal resolution in a hermetic package with an active area of 400 square centimeters. A key component of LAPPD is a chevron pair of large area (20 x 20 cm) MCPs. The manufacture of these large-area high performance MCPs has been enabled by the convergence of two technological breakthroughs. The first is the ability to produce large blocks of hollow, micronsized glass capillary arrays (GCAs) developed by Incom Inc. The Incom process is based on the use of an etchless “hollow-core” approach in the glass drawing process, eliminating the need to remove core material by chemical etching. The arrays are fabricated as large blocks that can be sliced to form large area wafers, without regard to the conventional limits of L/d (capillary length / pore diameter). Moreover, the glass used in these GCAs is physically more robust, does not have a tendency to warp, and has low levels of radioactive isotopes resulting in low dark noise. The second breakthrough is the advent of atomic layer deposition (ALD) coating methods and materials to functionalize GCAs to impart the necessary resistive and secondary emission properties suitable for large area detector applications. Recent results demonstrating the high performance, uniformity, and long term stability of the current MCP product are presented.

Secondary Emission Calorimeter (SEC)

This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) the experimenters of University of Chicago and California Institute of Technology, who have committed to participate in beam tests to be carried out during the 2014-2015 Fermilab Test Beam Facility program. The TSW is intended primarily for the purpose of recording expectations for budget estimates and work allocations. The experimenters propose using large-area micro-channel plates assembled without the usual bialkali photocathodes as the active element in sampling calorimeters, Modules without photocathodes can be economically assembled in a glove box and then pumped and sealed using the process to construct photomultipliers, This electromagnetic calorimeter is based on W and Pb absorber plates sandwiched with detectors. Measurements can be made with bare plates and absorber inside the vacuum vessel.

A design for large-area fast photo-detectors with transmission-line readout and waveform sampling

We present a preliminary design and the results of simulation for a photo-detector module to be used in applications requiring the coverage of areas of many square meters with time resolutions less than 10 picoseconds and position resolutions of less than a millimeter for charged particles. The source of light is Cherenkov light in a radiator/window; the amplification is provided by panels of micro-pores functionalized to act as microchannel plates (MCPs). The good time and position resolution stems from the use of an array of parallel 50 Ω transmission lines (strips) as the collecting anodes. The anode strips feed multi-GS/sec sampling chips which digitize the pulse waveform at each end of the strip, allowing a measurement of the time from the average of the two ends, and a 2-dimensional position measurement from the difference of times on a strip, and, in the orthogonal direction, the strip number, or a centroid of the charges deposited on adjacent strips. The module design is constructed so that large areas can be ‘tiled’ by an array of modules

Position Measurements with Micro-Channel Plates and Transmission lines using Pico-second Timing and Waveform Analysis

The anodes of Micro-Channel Plate devices are coupled to fast transmission lines in order to reduce the number of electronics readout channels, and can provide two-dimension position measurements using two-ends delay timing. Tests with a laser and digital waveform analysis show that resolutions of a few hundreds of microns along the transmission line can be reached taking advantage of a few pico-second timing estimation. This technique is planned to be used in Micro-channel Plate devices integrating the transmission lines as anodes.