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Bruce A. Schumm

Publications and source records attributed to Bruce A. Schumm.

15 recordsLinked to original sources
arXiv2022

Student-created physics problems as an independent and equitable assessment tool

Traditional high-stakes summative assessments--timed, in-class exams accounting for a large percentage of the term's overall grade--have often received criticism from the educational community. Such assessments tend to prize a particular "narrow bundle of skills", and have been shown in some contexts to produce disparate outcomes between different demographic groups. Alternative low-stakes assessments have shown potential to improve student engagement and close demographic gaps. In this paper, we document our use of an alternative form of assessment, in which students were asked to create and solve a problem of their own design.

physics.ed-ph↗
arXiv2020

Signal Development for Saturated Ultrafast Sensors with Impact Ionization Gain

A closed-form approximate expression is presented for the short time-frame development of silicon diode sensor signals in the context of high frame-rate detection of incident X-ray fluxes, in the limit that the X-ray absorption profile generates a longitudinally-uniform distribution of electron-hole pairs in the detector bulk. The expression represents the immediate time development of signals from diode sensors both with (LGAD) and without (PIN) gain, and presents a temporal scale associated with the onset of gain. Principles limiting the detection frame rate in the presence of electronic readout noise are discussed. Making use of an elemental simulation, the relative advantage of LGAD vs. PIN diode sensors is explored as a function of the effective electronic collection time. It is found that for an idealized LGAD sensor with a gain of 30, the gain provided by impact ionization yields an advantage relative to PIN diode sensors for frame rates as high as 10 GHz.

physics.ins-det↗
arXiv2017

Updated Results of a Solid-State Sensor Irradiation Study for ILC Extreme Forward Calorimetry

Detectors proposed for the International Linear Collider (ILC) incorporate a tungsten sampling calorimeter (`BeamCal') intended to reconstruct showers of electrons, positrons and photons that emerge from the interaction point of the collider with angles between 5 and 50 milliradians. For the innermost radius of this calorimeter, radiation doses at shower max are expected to reach 100 Mrad per year, primarily due to minimum-ionizing electrons and positrons that arise in the induced electromagnetic showers of e$^+$e$^-$ `beamstrahlung' pairs produced in the ILC beam-beam interaction. However, radiation damage to calorimeter sensors may be dominated by hadrons induced by nuclear interactions of shower photons, which are much more likely to contribute to the non-ionizing energy loss that has been observed to damage sensors exposed to hadronic radiation. We report here on prior highlights and recent results of SLAC Experiment T-506, for which several different types of semiconductor sensors were exposed to doses of radiation induced by showering electrons of energy 3.5-13.3 GeV. By embedding the sensor under irradiation within a tungsten radiator, the exposure incorporated hadronic species that would potentially contribute to the degradation of a sensor mounted in a precision sampling calorimeter. Depending on sensor technology, significant post-irradiation charge collection was observed for doses of several hundred Mrad.

physics.ins-det↗
arXiv2016

Updated Results of a Solid-State Sensor Irradiation Study for ILC Extreme Forward Calorimetry

Detectors proposed for the International Linear Collider (ILC) incorporate a tungsten sampling calorimeter (`BeamCal') intended to reconstruct showers of electrons, positrons and photons that emerge from the interaction point of the collider with angles between 5 and 50 milliradians. For the innermost radius of this calorimeter, radiation doses at shower max are expected to reach 100 Mrad per year, primarily due to minimum-ionizing electrons and positrons that arise in the induced electromagnetic showers of e+e- `beamstrahlung' pairs produced in the ILC beam-beam interaction. However, radiation damage to calorimeter sensors may be dominated by hadrons induced by nuclear interactions of shower photons, which are much more likely to contribute to the non-ionizing energy loss that has been observed to damage sensors exposed to hadronic radiation. We report here on the results of SLAC Experiment T-506, for which several different types of silicon diode and gallium-arsenide sensors were exposed to doses of radiation induced by showering electrons of energy 3.5-13.3 GeV. By embedding the sensor under irradiation within a tungsten radiator, the exposure incorporated hadronic species that would potentially contribute to the degradation of a sensor mounted in a precision sampling calorimeter. Depending on sensor technology, efficient charge collection was observed for doses as large as 270 Mrad.

physics.ins-det↗
arXiv2015

Updated Results of a Solid-State Sensor Irradiation Study for ILC Extreme Forward Calorimetry

Detectors proposed for the International Linear Collider (ILC) incorporate a tungsten sampling calorimeter (`BeamCal') intended to reconstruct showers of electrons, positrons and photons that emerge from the interaction point of the collider with angles between 5 and 50 milliradians. For the innermost radius of this calorimeter, radiation doses at shower-max are expected to reach 100 MRad per year, primarily due to minimum-ionizing electrons and positrons that arise in the induced electromagnetic showers of e+e- `beamstrahlung' pairs produced in the ILC beam-beam interaction. However, radiation damage to calorimeter sensors may be dominated by hadrons induced by nuclear interactions of shower photons, which are much more likely to contribute to the non-ionizing energy loss that has been observed to damage sensors exposed to hadronic radiation. We report here on the results of SLAC Experiment T-506, for which several different types of silicon diode and gallium-arsenide sensors were exposed to doses of radiation induced by showering electrons of energy 3.5-10.6 GeV. By embedding the sensor under irradiation within a tungsten radiator, the exposure incorporated hadronic species that would potentially contribute to the degradation of a sensor mounted in a precision sampling calorimeter. Depending on sensor technology, efficient charge collection was observed for doses as large as 220 MRad.

physics.ins-det↗
arXiv2011

Generic Microstrip R&D Topics at SCIPP: Longitudinal Charge Division and Length Limitations for Long Strips

We discuss results on the use of charge division to estimate the longitudinal position of charge deposition in silicon microstrip sensors, and on the intrinsic noise limitation of microstrip sensors in the limit of long, narrow strips. We find a resolution of \pm6% of the length of the sensor for a 10cm-long sensor. We also find that network effects significantly reduce sensor readout noise relative to naive expectations that arise from treating the detector resistance and capacitance as single discrete electronic components.

physics.ins-det↗
arXiv2011

Metastable Staus: Reconstructing Non-Prompt Tracks at the ILC with the SiD Detector

We have explored the reconstruction of kinks from the decay of metastable staus into a gravitino and a stau lepton in the radial region between the outer layer of the vertex detector and the second central tracking layer. After applying a cut on track multiplicity, we find a high efficiency for such events, with minimal background from Standard Model processes.

physics.ins-det↗
arXiv2007

Simulation of an All-Silicon Tracker

We present recent improvements in the performance of the reconstruction of non-prompt track in the SiD Detector Concept Design, including initial results on the effect of longitudinal segmentation in the SiD tracker. We also describe a generic tracking validation package developed at SCIPP.

physics.ins-det↗
arXiv2005

General Thoughts about Tracking for a Linear Collider Detector

Basic scaling laws are used to compare the relative capabilities of gaseous and solid-state tracking. Conclusions are drawn in the context of physics processes expected to be at the focus of studies at the International Linear Collider.

physics.ins-det↗
arXiv2005

Progress Towards a Long Shaping-Time Readout for Silicon Strips

We report on progress in the development of the LSTFE2 prototype front-end ASIC geared towards the readout of silicon microstrip sensors in a Linear Collider detector. We also discuss progress in the design of the back-end digital architecture for this readout scheme.

physics.ins-det↗
arXiv2004

Research and Development in Front-End Electronics for Future Linear Collider Detectors

To probe physics of interest a decade after the LHC begins to take data, the Linear Collider will need to have the capability of performing precision measurements of masses and couplings. We discuss the demands that this places on its associated detectors, and the status of and plans for continued R&D in front-end electronics that is necessary to meet these demands.

physics.ins-det↗
arXiv2001

Research and Development towards a Detector for a High Energy Electron-Positron Linear Collider

This exposition provides a detailed picture of ongoing and planned activities towards the development of a detector for a high-energy Linear Collider. Cases for which research and development activity does not exist, or needs to be bolstered, are identified for the various subsystems. The case is made that the full exploitation of the potential of a high-energy Linear Collider will require the augmentation of existing detector technology and simulation capability, and that this program should become a major focus of the worldwide particle physics community should the construction of a Linear Collider become likely.

hep-ex↗
arXiv2001

Update on the Measurement of alpha_S with a 500 GeV Linear Collider

An update on the prospects for the precise measurement of the strong coupling constant alpha_S at a high energy Linear Collider via the three-jet rate is presented. In particular, the issue of the distribution of center-of-mass energies of the identified q-qbar event sample, which can affect the determination of α_S at the scale Q^2=(500 GeV)^2$, is addressed.

hep-ex↗
arXiv1996

Identification of a sample of e+e- -> qq Events For the Precise Measurement of Alpha_S in High Energy Electron Positron Colliders

Based on the PYTHIA physics simulation package, and a fast simulation of the proposed detector for the Next Linear Collider, a set of cuts is identified which leads to a sample of e+e- -> qq events appropriate for the precise measurement of alpha_s in e+e- annihilation at sqrt(s) = 500 GeV/c^2. Using these cuts, the systematic uncertainty on alpha_s associated with correcting for selection cut biases and remaining non-e+e- -> qq (q ^= t) contamination is expected to be less than +/- 1%. This work was done as part of a study of the prospects for the precise measurement of alpha_s at future High Energy Physics facilities, undertaken for the 1996 Snowmass Workshop on New Directions in High Energy Physics.

hep-ex↗