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Chiu, Mickey

Publications and source records attributed to Chiu, Mickey.

Capacitively Coupled LAPPDs with 2D Pixelated Readout Planes for Time of Flight and Ring Imaging Cherenkov Applications

Large Area Picosecond Photon Detectors (LAPPDs) are micro-channel plate based photosensors featuring hundreds of square centimeters of sensitive area in a single package and capable of providing timing resolution on the order of 50 ps for single photon detection. However, LAPPDs currently do not exist in finely pixelated 2D readout configurations which, in addition to ighresolution timing, would also provide high spatial resolution required for Ring Imaging CHerenkov (RICH) detectors. One of the recent LAPPD models (Gen II) provides the opportunity to overcome the lack of pixellation by coupling an external readout to the sealed detector itself. The readout plane in this case is a simple printed circuit board (PCB) that can be laid out in a custom application-specific way for 1D or 2D sensitive area pixellation. This allows for a much shorter readout-plane prototyping cycle and provides unprecedented flexibility in choosing an appropriate segmentation that can be optimized for any particular detector need in terms of pad size, orientation, and shape.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Characteristics of fast timing MCP-PMTs in magnetic fields

Here, the motivation of this paper is to explore the parameters that affect the performance of Microchannel Plate Photomultiplier Tubes (MCP-PMTs) in magnetic fields with the goal to guide their design to achieve a high magnetic field tolerance. MCP-PMTs based on two different designs were tested. The magnetic field tolerance of MCP-PMT based on a design providing independently biased voltages showed a significant improvement (up to 0.7 T) compared to the one utilizing an internal resistor chain design (up to 0.1 T), indicating the importance of individually adjustable voltages. The effects of the rotation angle of the MCP-PMT relative to the magnetic field direction and of the bias voltage between the photocathode and the top MCP were extensively investigated using the MCP-PMT based on the independently biased voltage design. It was found that the signal amplitude of the MCP-PMT exhibits an enhanced performance at a tilt angle of ±8°, due to the 8°bias angle of the MCP pores. Fianlly, the maximum signal amplitude was observed at different bias voltages depending on the magnetic field strength.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Photons from thermalizing matter in heavy ion collisions

Here, we investigate the production of direct photons in heavy ion collisions within the modified bottom-up thermalization scenario, which we show to be related to the thermalizing Glasma framework. The dynamics of the parton system up to thermalization/ equilibration can be described by two momentum scales, by means of which we express the photon invariant yield excluding the prompt pQCD contribution. We derive an analytic formula, which provides an estimate of photon production from thermalizing matter for a wide range of collision systems and energies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Rate capability and magnetic field tolerance measurements of fast timing microchannel plate photodetectors

Microchannel plate photodetectors provide both picosecond time resolution and sub-millimeter position resolution, making them attractive photosensors for particle identification detectors of a future U.S. Electron Ion Collider. In this paper, we have tested the rate capability and magnetic field tolerance of 6 x 6 cm 2 microchannel plate photodetectors fabricated at Argonne National Laboratory. The microchannel plate photodetector is designed as a low-cost all-glass vacuum package with a chevron pair stack of next-generation microchannel plates functionalized by atomic layer deposition. The rate capability test was performed using Fermilab’s 120 GeV/c primary proton beam, and the magnetic field tolerance test was performed using a solenoid magnetic with tunable magnetic field strength up to 4 T. Finally, the measured gain of the microchannel plate photodetector is stable up to 75 kHz/cm 2 and varies depending on the applied magnetic field strength and the rotation angle relative to the magnetic field direction.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

PHENIX Fast TOF

This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of PHENIX Fast TOF group who have committed to participate in beam tests to be carried out during the FY2014 Fermilab Test Beam Facility program. The goals for this test beam experiment are to verify the timing performance of the two types of time-of-flight detector prototypes.

43 PARTICLE ACCELERATORS↗

T1044: sPHENIX Calorimetry Tests

The sPHENIX upgrade to the PHENIX detector is designed to study jets in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and address questions about the nature of the perfect fluid quark-gluon plasma. The upgrade consists of a 2 Tesla superconducting magnetic solenoid of radius 70 cm surrounded by electromagnetic and hadronic calorimeters with uniform coverage over a rapidity range of IT'ii < 1 and 2n in azimuth. The sPHENIX detector concept takes advantage of technological developments to enable a compact design with excellent performance. A tungsten-scintillator electromagnetic calorimeter read out with silicon photomultipliers (SiPMs) allows for a physically thin device, which can operate in a magnetic field, without the bulk of photomultiplier tubes and the need for high voltage distribution. The smaller electromagnetic calorimeter also allows the hadron calorimeter to be less massive, and the use of silicon photomultipliers for the hadron calorimeter allow for nearly identical electronic readout for the two major systems. The requirements for the sPHENIX electromagnetic calorimeter lead to a design that is compact (i.e. has a small Molie 're radius and short radiation length), has a high degree of segmentation (0.024 x 0.024 in TJ and

Mannel, Eric↗