About

Adam Harris is an Assistant Professor in the Department of Economics at Cornell University. His academic interests include industrial organizations, transportation economics, and the economics of artificial intelligence. He is involved in teaching courses such as Industrial Organization: A Computational Approach and Industrial Organization Workshop, and his research focuses on these areas, contributing to the understanding of market structures and technological impacts within economics. His professional activities include participating in workshops and conferences related to macroeconomics and industrial organization, and he is engaged in the academic community through his faculty role at Cornell.

Research topics

• Physics
• Particle physics
• Nuclear physics
• Computer Science
• Optics
• Quantum mechanics
• Astrophysics
• Geology
• Mathematics
• Algorithm
• Database
• Combinatorics
• Biology
• Operating system
• Real-time computing
• Computer hardware
• Telecommunications
• Statistics

Selected publications

• Athermal phonon collection efficiency in diamond crystals for low mass dark matter detection

  Physical review. D/Physical review. D. · 2025-04-15

  articleOpen access

  We explored the efficacy of lab-grown diamonds as potential target materials for the direct detection of sub-GeV dark matter (DM) using metallic magnetic calorimeters (MMCs). Diamond, with its excellent phononic properties and the low atomic mass of the constituent carbon, can play a crucial role in detecting low mass dark matter particles. The relatively long electron-hole pair lifetime inside the crystal may provide discrimination power between the DM-induced nuclear recoil events and the background-induced electron recoil events. Utilizing the fast response times of the MMCs and their unique geometric versatility, we deployed a novel methodology for quantifying phonon dynamics inside diamond crystals. We demonstrated that lab-grown diamond crystals fabricated via the chemical vapor deposition (CVD) technique can satisfy the stringent quality requirements for sub-GeV dark matter searches. The high-quality polycrystalline CVD diamond showed a superior athermal phonon collection efficiency compared to that of the reference sapphire crystal, and achieved energy resolution 62.7 eV at the 8.05 keV copper fluorescence line. With this energy resolution, we explored the low-energy range below 100 eV and confirmed the existence of so-called low-energy excess (LEE) reported by multiple cryogenic experiments.

  PublisherOA PDFDOI

• Search for Nearly Mass-Degenerate Higgsinos Using Low-Momentum Mildly Displaced Tracks in $pp$ Collisions at $\sqrt{s}$ = 13 TeV with the ATLAS Detector

  arXiv (Cornell University) · 2024

  • Physics
  • Particle physics
  • Nuclear physics

  Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is $\mathcal{O}(1 \text{GeV})$. This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from $0.3$ GeV to $0.9$ GeV is excluded at 95$\%$ confidence level, with a maximum reach of approximately $170$ GeV in the Higgsino mass.

  DOI

• Diamond and SiC Detectors for Rare Event Searches

  Journal of Low Temperature Physics · 2024-06-21 · 5 citations

  articleOpen access
  PublisherOA PDFDOI

• Latest results from the RD42 collaboration on the radiation tolerance of polycrystalline diamond detectors

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2024-02-23 · 4 citations

  articleOpen access
  PublisherOA PDFDOI

• Development of the Beam Conditions Monitoring Prime system for beam abort and luminosity monitoring in ATLAS based on a segmented polycrystalline CVD diamond system and dedicated front-end ASIC

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2024-02-23

  articleOpen access

  The High Luminosity upgrade of Large Hadron Collider (HL-LHC) will increase the LHC luminosity and with it the density of particles on the detector by an order of magnitude. For protecting the inner silicon detectors of the ATLAS experiment and for monitoring the delivered luminosity, a radiation hard beam monitor was developed based on polycrystalline Chemical Vapor Deposition (pCVD) diamond detectors and a new dedicated rad-hard front-end ASIC . Due to the large range of particle flux through the detector, flexibility is very important. To satisfy the requirements imposed by the HL-LHC, our solution is based on segmenting diamond sensors into devices of varying size and reading them out with new multichannel readout ASICs divided into two independent parts — each of them serving one of the tasks of the system. This paper describes the system design including detectors, electronics, mechanics and services and presents preliminary results from the most recent detectors fabricated, using our prototype ASIC with data from beam tests at CERN.

  PublisherDOI

• Development of the BCM system and readout for ATLAS

  2024-02-05

  articleOpen access

  The High Luminosity upgrade of the Large Hadron Collider will increase the LHC luminosity and with it the density of particles on the detector by an order of magnitude. For protecting the inner silicon detectors of the ATLAS experiment and for monitoring the delivered luminosity, a radiation hard beam monitor has been developed. A set of detectors has been developed based on polycrystalline Chemical Vapor Deposition diamonds and a new dedicated radiation-hard front-end ASIC. To satisfy the requirements imposed by the HL-LHC, our solution is based on segmenting diamond sensors into devices of varying size and reading them out with new multichannel readout ASICs divided into two independent parts, each of them serving one of the tasks of the system. This document describes the system design including detectors, electronics and the ATLAS FPGA FELIX based readout. Additionally, it presents preliminary results of the readout with data from beam tests from 2023 at the SPS beam line at CERN.

  PublisherDOI

• Progress in Diamond Detectors

  2023-03-13 · 1 citations

  preprintOpen access

  Detectors based on Chemical Vapor Deposition (CVD) diamond have been used successfully in Luminosity and Beam Condition Monitors (BCM) in the highest radiation areas of the LHC. Future experiments at CERN will accumulate an order of magnitude larger fluence. As a result, an enormous effort is underway to identify detector materials that can operate under fluences of 1 · $10^{16}$ n cm$^{−2}$ and 1 · $10^{17}$ n cm$^{−2}$. Diamond is one candidate due to its large displacement energy that enhances its radiation tolerance. Over the last 30 years the RD42 collaboration has constructed diamond detectors in CVD diamond with a planar geometry and with a 3D geometry to extend the material’s radiation tolerance. The 3D cells in these detectors have a size of 50 μm×50 μm with columns of 2.6 μm in diameter and 100 μm×150 μm with columns of 4.6 μm in diameter. Here we present the latest beam test results from planar and 3D diamond pixel detectors.

  PublisherDOI

• A Fast, Low-Jitter, and Low-Time-Walk Multi-Channel Front-End IC for Diamond and Silicon Radiation Detectors

  IEEE Transactions on Nuclear Science · 2023-06-07 · 7 citations

  article

  This article presents the design and implementation of a radiation-hardened analog front-end (AFE) integrated circuit (IC) developed for interfacing with solid state ionizing radiation detectors, providing accurate amplitude and time-of-arrival measurements. The AFE is designed for use in the Beam Conditions Monitor Prime (BCM’) of the ATLAS experiment at the Large Hadron Collider (LHC). The proposed AFE is comprised of four channels, allowing for re-configuration to operate as either a low-noise high-gain amplifier for beam luminosity measurements or a high-linearity low-gain amplifier for beam abort functionality. Each of the AFE channels consists of a low-noise trans-impedance amplifier (TIA) optimized for minimal jitter and amplitude noise, a second-stage differential amplifier, followed by a fully differential constant fraction discriminator (CFD) to provide an amplitude independent time pick-off with a wide dynamic range. The CFD utilizes a new all-pass filter delay topology and high-performance zero-crossing detector (ZCD) to minimize time-walk. The core of each AFE channel occupies an area of 0.06 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in a 65 nm CMOS technology and consumes 57 mW, including the drivers. The measured AFE chips achieve 1 ns pulse rise time, 130 electron baseline equivalent noise charge (ENC), and <25 ps root mean square (rms) jitter at 1 fC input charge. To the authors’ best knowledge, this work demonstrates the lowest published time-walk of ±6 ps across 30 dB signal dynamic range. Furthermore, irradiated AFEs are shown to tolerate up to 225 Mrad total ionizing dose with no significant degradation in measured performance characteristics.

  PublisherDOI

• Development of a System for Beam Abort and Luminosity Determination at the HL-LHC based on polycrystalline CVD diamond

  Journal of Physics Conference Series · 2022-11-01 · 1 citations

  articleOpen access

  The high luminosity upgrade of Large Hadron Collider will increase its luminosity by an order of magnitude increasing with it the density of particles on the detector. For protecting the inner detectors of experiments and for monitoring the delivered luminosity, a radiation hard beam monitor is being developed. Text describes the proposed system’s principles of operation and its design. It details on the poly-crystalline chemical vapor deposition diamonds as sensor material, a dedicated radiation hard ASIC, as well as on electronics and data processing. The latter finally offers beam abort and luminosity measurement functionalities of the system.

  PublisherOA PDFDOI

• Radiation tolerance of diamond detectors

  Journal of Physics Conference Series · 2022-11-01 · 7 citations

  articleOpen access

  Diamond is used as detector material in high energy physics experiments due to its inherent radiation tolerance. The RD42 collaboration has measured the radiation tolerance of chemical vapour deposition (CVD) diamond against proton, pion, and neutron irradiation. Results of this study are summarized in this article. The radiation tolerance of diamond detectors can be further enhanced by using a 3D electrode geometry. We present preliminary results of a poly-crystalline CVD (pCVD) diamond detector with a 3D electrode geometry after irradiation and compare to planar devices of roughly the same thickness.

  PublisherOA PDFDOI

Frequent coauthors

• L. Xu

  Tsinghua University

  2235 shared

• T. Beau

  Consejo Nacional de Investigaciones Científicas y Técnicas

  2222 shared

• H. Bachacou

  Institut de Recherche sur les Lois Fondamentales de l'Univers

  2021 shared

• A. Formica

  CEA Paris-Saclay

  2014 shared

• L. Chevalier

  CEA Paris-Saclay

  2006 shared

• J. Ocariz

  Université Paris Cité

  2001 shared

• E. Rossi

  1944 shared

• L. Schoeffel

  CEA Paris-Saclay

  1905 shared