arXiv subjects

G. McIntyre

Publications and source records attributed to G. McIntyre.

4 recordsLinked to original sources

arXiv2019

Higher order mode damper for low energy RHIC electron cooler SRF booster cavity

To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under commissioning at BNL. The Linac of LEReC is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with rms dp/p less than 5e-4. A 704 MHz superconducting radio frequency (SRF) booster cavity in this Linac provides up to 2.2 MeV accelerating voltage. With such a low energy and very demanding energy spread requirement, control of Higher Order Modes (HOMs) in the cavities becomes critical and needs to be carefully evaluated to ensure minimum impact on the beam. In this paper, we report the multiphysics design of the HOM damper for this cavity to meet the energy spread requirement, as well as experimental results of the cavity with and without the HOM damper.

physics.acc-ph↗

arXiv2018

Design and test of 704 MHz and 2.1 GHz normal conducting cavities for Low Energy RHIC electron Cooler

The Low Energy RHIC electron Cooler (LEReC) is currently under commissioning at BNL to improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon. The linac of LEReC consists of a DC photoemission gun, one 704 MHz superconducting radio frequency (SRF) booster cavity, and three normal conducting cavities. It is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with peak-to-peak momentum spread dp/p of less than 7e4. Two of the three normal conducting cavities will be used in LEReC for energy spread correction. A single-cell 704 MHz cavity for energy de-chirping and a three-cell 2.1 GHz third harmonic cavity for RF curvature correction. In this paper, we present the designs and RF test results of these two cavities.

physics.acc-ph↗

arXiv2014

eRHIC Design Study: An Electron-Ion Collider at BNL

This document presents BNL's plan for an electron-ion collider, eRHIC, a major new research tool that builds on the existing RHIC facility to advance the long-term vision for Nuclear Physics to discover and understand the emergent phenomena of Quantum Chromodynamics (QCD), the fundamental theory of the strong interaction that binds the atomic nucleus. We describe the scientific requirements for such a facility, following up on the community-wide 2012 white paper, 'Electron-Ion Collider: the Next QCD Frontier', and present a design concept that incorporates new, innovative accelerator techniques to provide a cost-effective upgrade of RHIC with polarized electron beams colliding with the full array of RHIC hadron beams. The new facility will deliver electron-nucleon luminosity of 10^33-10^34 cm-1sec-1 for collisions of 15.9 GeV polarized electrons on either 250 GeV polarized protons or 100 GeV/u heavy ion beams. The facility will also be capable of providing an electron beam energy of 21.2 GeV, at reduced luminosity. We discuss the on-going R&D effort to realize the project, and present key detector requirements and design ideas for an experimental program capable of making the 'golden measurements' called for in the EIC White Paper.

physics.acc-ph↗

arXiv2006

The effect of externally applied pressure on the magnetic behavior of Cu2Te2O5(BrxCl{1-x})2

The effect of externally applied pressure on the magnetic behavior of Cu2Te2O5(BrxCl{1-x})2 with x = 0, 0.73 and 1, is investigated by a combination of magnetic susceptibility, neutron diffraction and neutron inelastic scattering measurements. The magnetic transition temperatures of the x = 0 and 0.73 compositions are observed to increase linearly with increasing pressure at a rate of 0.23(2) K/kbar and 0.04(1) K/kbar respectively. However, the bromide shows contrasting behavior with a large suppression of the transition temperature under pressure, at a rate of -0.95(9) K/kbar. In neutron inelastic scattering measurements of Cu2Te2O5Br2 under pressure only a small change to the ambient pressure magnetic excitations were observed. A peak in the density of states was seen to shift from ~5 meV in ambient pressure to ~6 meV under an applied pressure of 11.3 kbar, which was associated with an increase in the overall magnetic coupling strength.

cond-mat.mtrl-sci↗