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CORNELL LABORATORY FOR ACCELERATOR-BASED SCIENCES AND EDUCATION

REU 2023 Projects

  MENTOR STUDENT PROJECT
14 Matt Andorf, Tyler Wu Zahin Ritee

Presentation, Final Report
"A new source of spin-polarized photoelectrons?"

Abstract:
The alkali-antimonide photocathodes are robust photoemitters but do not generate a spin-polarized beam directly. There is some evidence that when brought to into a state called negative electron affinity (NEA), an alkali-antimonide photocathode can produce a spin-polarized beam. We propose to study if Rb3Sb can be brought to NEA with a layer of Cs3Sb, and if so, can it function as a spin-polarized source?

Project goals: Use Density Functional Theory to...

  • Compute spin-orbit splitting values at the valence band maximum.

  • Determine if NEA be achieved.

  • Is a small amount of positive electron affinity permissible?

  • What other alkali-antimonides might work?

1 Matt Signorelli Anna Connelly

Presentation, Final Report
"Spin matching for the Electron-Ion Collider"

Abstract:
The Electron-Ion Collider (EIC) to be built at Brookhaven National Laboratory will allow for spin-polarized collisions of electrons and light-ions at a wide range of energies. The design of a new storage ring to store the polarized electron bunches - the aptly-named Electron Storage Ring (ESR) - is currently in progress. The ESR must be carefully designed so that the depolarizing effects of synchrotron radiation are minimized and polarization requirements are satisfied. Currently, this requirement needs to be verified for the 5 and 10 GeV energy cases of a new lattice geometry.

In this project, the REU student will gain a theoretical and computational foundation in accelerator physics and spin dynamics in particle accelerators. The student will use the Bmad accelerator software toolkit to construct a spin-matched ESR lattice, and then perform an analysis of the polarization. The results of the project will have direct importance to the design of the EIC.

2 Jonathan Unger Laura Smith

Presentation, Final Report
"Modelling the Electron-Ion Collider’s Rapid Cycling Synchrotron"

Abstract:
The Electron-Ion Collider (EIC) to be built at Brookhaven National Laboratory will explore collisions of electrons and ions at a wide range of energies. For the electrons, this energy range is provided by accelerating through the Rapid Cycling Synchrotron (RCS). Before being injected into the Electron Storage Ring (ESR) for collision with the ions, a bunch train is injected into the RCS at 400MeV and accelerated over many thousands of turns to 5, 10, or 18GeV. During the quick energy ramp several challenges are present, such as maintaining polarization, merging the bunch train into a single bunch, and reducing particle loss.

In this project, the REU student will assist in the creation and use of simulations of portions of the RCS, which can then be combined into a complete simulation. This work will be done through the use of Bmad, an accelerator toolkit, and its associated programs.

3 Matt Gordon, Michael Kaemingk Shwetha Prakash

Presentation, Final Report
"Designing and building a focusing magnet"

Abstract:
In accelerators, magnets are primarily used for two purposes: steering and focusing. In the case of a focusing magnet, we desire the shortest possible focal length, and a lack of aberrations in the focusing (similar to astigmatism in your vision). In addition, the magnet must be able to work efficiently with the available power sources, and not overheat. In this project, we will be improving on the design of an existing solenoid magnet, in order to improve it in all of those areas, and then we will build it and test it with our particle beam.

4 Adam Bartnik, Michael Kaemingk Matthew Gootman

Presentation, Final Report
"Benchmarking space charge simulations"

Abstract:
The backbone of accelerator design and operation is an accurate numerical model of the accelerator. In the beginning sections of an accelerator, where the beam's energy is not yet very large, the mutual repulsion of the charged particles in the beam, which is called the "space charge" force in accelerator physics, is a primary source of the degradation of the quality of the beam. As such, simulations must be able to accurately model this space charge force. This project will benchmark a few existing simulation packages against each other, in order to help us pick which models to use in the future.

5 Suchismita Sarker Louis Cedarbaum

Presentation, Final Report
"Does Bluesky@CHESS help to enable machine learning efficiently?"

Abstract:
Synchrotrons are the place for multi-facility collaboration. The challenge is the volume of the dataset, the growing scale of open-source scientific Python library ecosystems for data analysis (including data science, sharing tools using GitHub or others), and finally, the existing friction between the facility software and the domain science. To address these challenges, the Bluesky Project was developed at NSLSII as an end-to-end solution encompassing hardware integration, experiment specification, online visualization, and data management. 

Currently, the most popular software for instrument control and data analysis throughout the synchrotron facility is SPEC and certain advantages make SPEC truly unique. However, as we go towards using faster detectors, managing metadata, streamlining data pipeline software towards data science, and finally, on-the-fly data reduction and closed-loop decision-making advantages of Bluesky-based data collectors quickly surpass SPEC and other older data collectors. There is an urgent need to truly decide how to go forward and benefit from the advantages of Bluesky and overcome its limitations. 

In this project, the REU student will learn to implement Ophyd for communication with synchrotron devices. The project is based on developing and completely implementing a Bluesky-based data collector; therefore, a CS background student with Python programming experience is preferred.

6 Jim Crittenden Wyatt Carbonell

Presentation, Final Report
"Evaluation of Systematic Errors in Beam Size Measurement Using Sextupole Magnets"

Abstract:
Variations in field strength of a sextupole magnet in a storage ring result in changes to the orbit, betatron phase functions and tunes which depend on the position of the beam relative to the center of the sextupole and on the beam size. Such measurements have been carried out with 6 GeV positrons at the Cornell Electron Storage Ring (CESR) since February 2021. Variations of strength in each of the 76 sextupoles provide measurements of difference orbits, phase and coupling functions. An off-line optimization procedure applied to these difference measurements determines the horizontal and vertical orbit kicks and the normal and skew quadrupole kicks corresponding to the strength changes. Continuously monitored tune changes during the sextupole strength scans provide a redundant, independent determination of the two quadrupole terms.

This project provides the REU participant the opportunity to perform data analysis emphasizing the accuracy with which beam size, sextupole strength calibrations, and horizontal and vertical sextupole misalignments can be determined. There will also be opportunities to join the data-taking shifts which provide the ongoing measurements with the CESR positron beam. The current status of the measurements and analysis, as well as links to presentations and relevant publications are available here. The results of this project will be submitted to the 15th International Particle Accelerator Conference to take place in the spring of 2024 in Nashville, Tennessee.

7 Nicole Verboncoeur and Neil Stilin Emily Rapp

Presentation, Final Report
"Exploring Superconducting Radio-Frequency Cavity Failure Mechanisms Through Temperature Mapping"

Abstract:
Superconducting radio frequency (SRF) cavities are one of the vital organs of an accelerator -- improving their performance allows for higher beam energies, which opens new frontiers for high energy physics. Understanding how and why SRF cavities quench (lose superconductivity) is very important for improving SRF cavity performance.

For this project, a student will explore quench data taken using Cornell's high speed temperature mapping system, looking for efficient and automated ways to find and characterize different types of quenches. The student will also use this temperature data to find and compare jumps in localized magnetic fields. This project also includes the opportunity to observe and assist with hands-on research activities in addition to the computational component of the project.

8 Liana Shpani and Thomas Oseroff Katherine Indyk

Presentation, Final Report
"Analysis of quality factor measurements for SRF cavities"

Abstract:
Superconducting radiofrequency (SRF) cavities are a critical component in modern particle accelerators. The quality factor and accelerating gradient are essential metrics when evaluating the performance of an SRF cavity. This REU project will focus on optimizing and testing an RF analysis code in MatLab.

Additionally, the student will have the opportunity to shadow and assist in parts of an cryogenic superconducting RF performance test to gain a better understanding of the experimental process. This project will also provide an opportunity to learn about the computational and experimental aspects of SRF cavities, which will be beneficial for a future career in experimental science.

9 Jose Monroy Marcos Acero

Presentation, Final Report
"Optimizing thermal management in a particle tracking detector"

Abstract:
A particle tracking detector is being developed at Cornell for an upgrade of the CMS experiment at CERN. The sensors are silicon pixel devices which are at risk of "thermal runaway" after significant radiation has been accumulated. Careful attention to thermal management in detector design and construction is needed to avoid this catastrophic outcome. The student on this project will work with a robotic assembly tool, writing code and performing studies to develop assembly techniques and parameters that will ensure that thermal pathways are robust.

10 Abigail Crites Francie Wharton

Presentation, Final Report
"Hardware Testing for TIME (The Tomographic Ionized Carbon Intensity Mapping Experiment)"

Abstract:
TIME (Tomographic Ionized Carbon Intensity Mapping Experiment) is a mm-wavelength spectrometer designed to probe the universe across cosmic time using [CII] line intensity mapping. The student will collaborate with the TIME team on hardware testing of the mm-wavelength spectrometer detectors and thermo-mechanical supports. Additionally they will develop Python routines to support this testing.

11 Gabriel Gaitan, Nathan Sitaraman Gregory Kenning

Presentation, Final Report
"Modeling of Nb3Sn Growth via Chemical Vapor Deposition and Vapor Diffusion"

Abstract:
Nb3Sn is the most promising alternative material for achieving superior performance in Superconducting Radio-Frequency (SRF) cavities, outstripping the conventional Nb cavities now used in accelerators. Chemical vapor deposition (CVD) is an alternative to the predominantly used vapor-diffusion-based Nb3Sn growth technique and it might allow for reaching superior RF performance.

Cornell University is developing a remote plasma-enhanced chemical vapor deposition (CVD) system to complement the currently operating vapor diffusion furnace used for Nb3Sn deposition. This REU project will focus on modeling the transport and deposition of chemical precursors in gas form on a cavity surface to form Nb3Sn or other superconducting materials.

The student will learn to use Ansys Fluent to model the gas flow in a complicated geometry and determine the best flow regime for growing a uniform film. Another project, depending on the student interest, could be to create a Sn and SnCl2 diffusion model for the Nb3Sn vapor diffusion furnace that would use a random walk-like model to determine vapor deposition as a function of geometry and other relevant like temperature and pressure.

12 Azriel Finstere Taylor Ray

Presentation, Final Report
"Automated Quantification of Compound Photocathode Composition using X-ray Photoemission Spectroscopy"

Abstract:
X-ray photoemission spectroscopy (XPS) is a powerful tool for the quantitative analysis of near-surface structure. An x-ray beam is used to excite core electrons from the surface. The energies of the emitted photoelectrons are then analyzed to determine both the identity and the oxidation state of all atoms in the near-surface region (except H).

There are two challenges in quantifying these spectra. First, some of the photoelectrons inelastically scatter before being ejected. These photoelectrons contribute to a complicated "background" which must be removed before analysis. Second, photoelectrons from deeper structures are scattered more than photoelectrons from surface structures. As a result, quantitative analysis requires a model of the emitting surface.

The summer researcher will develop an automated analysis package for the quantification of protected cesium antimonide photocathodes. A student with previous programming experience (in any language) and an interest in data analysis would be a good fit for this project. As time allows, the student will also learn to acquire x-ray photoemission spectra of photocathodes in a ultrahigh vacuum analysis chamber.

13 Steve Meisburger Simon Hempel-Costello

Presentation, Final Report
"Optical spectroscopy of metalloprotein crystals for monitoring reaction intermediates in time-resolved X-ray diffraction"

Abstract:
Macromolecular crystallography (MX) is the premier technique for observing protein structures at atomic resolution, and it contributes to fundamental discoveries in biochemistry, biophysics, and medicine. The MX program at CHESS is developing new instrumentation to support time-resolved X-ray crystallography experiments on electron transfer reactions in enzymes. A key requirement is the ability to measure the oxidation state of enzyme cofactors during the experiment and thus correlate chemical information with structural changes on various timescales.

During the summer of 2023, our team will design and construct a multi-modal micro-spectrometer that will eventually be integrated into the MX beamline ID7B2. The REU student will assist in mechanical and optical design and construction, and will complete a project to measure electronic structure changes in crystals of myoglobin upon binding of a small molecule. As part of the research experience, the student will receive training in MX data collection at ID7B2, light optics and mechanical design, laboratory practices, and protein crystallization techniques. Interest in data analysis would be a good fit for this project. As time allows, the student will also learn to acquire x-ray photoemission spectra of photocathodes in a ultrahigh vacuum analysis chamber.