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Papers by Sherwood Parker

Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment, 2006

Many systems in medicine, biology, high-energy physics, and astrophysics require large area radia... more Many systems in medicine, biology, high-energy physics, and astrophysics require large area radiation sensors. In most of these applications, minimizing the amount of dead area or dead material is crucial. We have developed a new type of silicon radiation sensor in which the device is active to within a few microns of the mechanical edge. Their perimeter is made by a plasma etcher rather than a diamond saw. Their edges can be defined and also passivated by growing, in an intermediate step, a field oxide on the side surfaces. In this paper, the basic architecture and results from a synchrotron beam test are presented.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008

3D-electrode pixel detectors are proposed in which the bias electrodes are connected to form a st... more 3D-electrode pixel detectors are proposed in which the bias electrodes are connected to form a strip readout on the same or opposite side of the sensor. It can provide a fast trigger and significantly increase spatial resolution in both directions. This combination is also possible with double-sided processing in planar technology. A second paper (“Dual Readout—3D Direct/Induced-Signals Pixel Systems”) will

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013

ABSTRACT 3D silicon sensors, where plasma micromachining is used to etch deep narrow apertures in... more ABSTRACT 3D silicon sensors, where plasma micromachining is used to etch deep narrow apertures in the silicon substrate to form electrodes of PIN junctions, were successfully manufactured in facilities in Europe and USA. In 2011 the technology underwent a qualification process to establish its maturity for a medium scale production for the construction of a pixel layer for vertex detection, the Insertable B-Layer (IBL) at the CERN-LHC ATLAS experiment. The IBL collaboration, following that recommendation from the review panel, decided to complete the production of planar and 3D sensors and endorsed the proposal to build enough modules for a mixed IBL sensor scenario where 25% of 3D modules populate the forward and backward part of each stave. The production of planar sensors will also allow coverage of 100% of the IBL, in case that option was required. This paper will describe the processing strategy which allowed successful 3D sensor production, some of the Quality Assurance (QA) tests performed during the pre-production phase and the production yield to date.

$Research paper thumbnail of Search for the Decay μ^{+}→e^{+}γ$

Physical Review Letters, 1986

This Letter reports a new experimental search for the family-number-nonconserving decay μ + →e + ... more This Letter reports a new experimental search for the family-number-nonconserving decay μ + →e + γ. There is no evidence for the presence of this decay mode. The upper limit for the branching ratio is Γ(μ→eγ) / Γ(μ→eνν̅ )<4.9×10 -11 (90% confidence limit).

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

ABSTRACT Dividing 3D active-edge silicon sensors into separate sections with a triple-wall sandwi... more ABSTRACT Dividing 3D active-edge silicon sensors into separate sections with a triple-wall sandwich of two trench electrodes separated by an insulating layer, will allow two or more bias voltages to be used simultaneously. Such sensors could be fabricated with only a single group of low-temperature additional steps and may be necessary to prevent a new form of radiation-damage failure in non-uniform radiation fields.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1990

Silicon strip vertex detector consisting of 36 independent detector modules is being constructed ... more Silicon strip vertex detector consisting of 36 independent detector modules is being constructed for use in the Mark II detector at a SLAC Linear Collider. This paper describes a method for determining the relative alignment of the modules to a precision better than the 5 μm intrinsic ...

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003

The LHC (Large Hadron Collider) is currently under construction at CERN, the European Laboratory ... more The LHC (Large Hadron Collider) is currently under construction at CERN, the European Laboratory for Particle Physics based in Geneva. The experiments at this accelerator will use substantial numbers of silicon detectors. These are close to the interaction point and will be exposed to very high fluences ( up to 10 15 particles cm À2 ) during their operating life. Such detectors are crucial to the disentanglement of important decay events and it is vital to guarantee a homogeneous reliable performance during their operation. Parameters like the charge collection efficiency (CCE) and response time will be discussed. Limitations of present technologies will be analysed and future strategies explored. Results obtained using alternative detector designs, such as 3D geometry, material engineering by oxygen diffusion and unconventional operational conditions are surveyed. r

IEEE Transactions on Nuclear Science, 2000

3D detectors with electrodes penetrating through the silicon wafer and covering the edges were te... more 3D detectors with electrodes penetrating through the silicon wafer and covering the edges were tested in the SPS beam line X5 at CERN in autumn 2003. Detector parameters including efficiency, signal-to-noise ratio, and edge sensitivity were measured using a silicon telescope as a reference system. The measured sensitive width and the known silicon width were equal within less than 10 m.