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Title: Microwave Superconducting Accelerators and Precision Sub-Atomic, Atomic and Molecular Physics at Jefferson Lab

Abstract

No abstract prepared.

Authors:
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
887162
Report Number(s):
JLAB-ACC-05-451; DOE/ER/40150-4999
TRN: US0604215
DOE Contract Number:
AC05-84ER40150
Resource Type:
Conference
Resource Relation:
Conference: Old Dominion University Physics Colloquium, Norfolk, VA, 15-Nov-05
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; ACCURACY; PHYSICS

Citation Formats

Chattopadhyay, Swapan. Microwave Superconducting Accelerators and Precision Sub-Atomic, Atomic and Molecular Physics at Jefferson Lab. United States: N. p., 2005. Web.
Chattopadhyay, Swapan. Microwave Superconducting Accelerators and Precision Sub-Atomic, Atomic and Molecular Physics at Jefferson Lab. United States.
Chattopadhyay, Swapan. Tue . "Microwave Superconducting Accelerators and Precision Sub-Atomic, Atomic and Molecular Physics at Jefferson Lab". United States. doi:. https://www.osti.gov/servlets/purl/887162.
@article{osti_887162,
title = {Microwave Superconducting Accelerators and Precision Sub-Atomic, Atomic and Molecular Physics at Jefferson Lab},
author = {Chattopadhyay, Swapan},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}

Conference:
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  • A non-invasive monitor has been implemented for the relative phase of the beam and the accelerating RF of each of the two CW superconducting linacs at TJNAF. Its noise level and resolution are below 0.1 degrees at beam currents as low as 2 microamperes, and it has been successfully tested for use in feedback correction for the overall RF accelerating phase of each linac. The 70 MHz frequency reference in each linac is phase modulated by approximately {+-} 0.05 degrees at different frequencies (383 and 397 Hz). A single analog beam position signal from a dispersive region is used tomore » monitor the resulting micron-level position modulation via off-the-shelf lock-in amplifiers, which also supply the modulation signals. The off-crest phase is proportional to the first harmonic coefficient of the energy modulation. This technique can be applied as well to pulsed machines and to systems for which the beam-to-RF relative phase may be non-zero. Other applications are discussed.« less
  • The authors present here recent progress on the experimental study of the neutron spin structure at Jefferson Lab Hall A. They focus on two precision experiments. The physics motivation and the experimental setup will be described first. Then they present results for the neutron spin asymmetry A{sub 1}{sup n} and results for spin-flavor decomposition of the nucleon spin in the valence quark region, and preliminary results for the neutron spin structure function g{sub 2}{sup n} at low Q{sup 2}.
  • Spin structure functions provide basic information about the spin of the quark distributions inside the nucleon. Experimental understanding of the nucleon spin in the kinematic region where the three basic (''valence'') quarks dominate the nucleon wave function is still rather poor. Jefferson lab, with its high quality, high polarization continuous electron beam, and a high density polarized 3He target in experimental Hall A, provides the ideal opportunity to gather neutron spin structure data in the valence region with unprecedented precision. Two high precision neutron spin structure measurements were completed in Hall A last summer. The first experiment measured the spinmore » asymmetry A1(N) in the valence region while in second experiment higher-twist effects were studied via measurements of gn2. The planed upgrade of Jefferson lab CEBAF accelerator to 12 GeV will significantly increase the accessible kinematic range and the precision of these measurements.« less
  • The first experiment E89-009/HNSS has made the key demonstration and feasibility test on the electroproduction of hypernuclei. Based on the experiences learned, the newly approved experiment, E01-011, is under preparation with a new method in tagging the scattered electrons and a newly designed and built kaon spectrometer, that optimize the usage of electron beam for high precision hypernuclear spectroscopy. Comparing to HNSS, the hypernuclear yield and signal over background ratio will be increased by about 56 and 10 times, respectively. Most importantly, we expect to obtain an energy resolution of about 300 keV. This experimental setup will open a doormore » for high yield, high quality, and high precision hypernuclear spectroscopic study in a wide mass range. The immediate goal of E01-011 is to study hypernuclei in the medium heavy region.« less
  • We present here recent progress on the experimental study of the neutron spin structure at Jefferson Lab Hall A. We focus on two precision experiments. The physics motivation and the experimental setup will be described first. Then we present results for the neutron spin asymmetry A{sup n}{sub 1} and results for spin-flavor decomposition of the nucleon spin in the valence quark region, and preliminary results for the neutron spin structure function g{sup n}{sub 2} at low Q2.