Download or read book Compton Polarimeter for Qweak Experiment at Jefferson Laboratory written by David Zou and published by . This book was released on 2011 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Qweak experiment at Jefferson Lab aims to make the first precision measurement of the proton's weak charge, QP = 1 - 4 sin 2 9w at Q2 = 0.026GeV 2 . Given the precision goals in the Qweak experiment, the electron beam polarization must be known to an absolute uncertainty of 1%. A new Compton polarimeter has been built and installed in Hall C in order to make this important measurement. Compton polarimetry has been chosen for its ability to deliver continuous on-line measuremnts at high currents necessary for Qweak (up to 180pzA). In this thesis, we collected and analyzed electron beam polarization data using the Qweak Compton polarimeter. Currently, data from the Compton can already be used to calculate preliminary values of experimental physics asymmetries and also the electron beam polarization. These preliminary results are promising indications that Qweak will be able to meet its stated precision goals.
Download or read book Preliminary Results from Integrating Compton Photon Polarimetry in Hall A of Jefferson Lab written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide range of nucleon and nuclear structure experiments in Jefferson Lab's Hall A require precise, continuous measurements of the polarization of the electron beam. In our Compton polarimeter, electrons are scattered off photons in a Fabry-Perot cavity; by measuring an asymmetry in the integrated signal of the scattered photons detected in a GSO crystal, we can make non-invasive, continuous measurements of the beam polarization. Our goal is to achieve 1% statistical error within two hours of running. We discuss the design and commissioning of an upgrade to this apparatus, and report preliminary results for experiments conducted at beam energies from 3.5 to 5.9 GeV and photon rates from 5 to 100 kHz.
Download or read book From Parity Violation to Hadronic Structure and more written by K. de Jager and published by Springer Science & Business Media. This book was released on 2008-06-21 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the third international workshop on From Parity Violation to Hadronic Structure and More. The many applications of parity violation are way beyond the scope of what Lee and Yang could have imagined fifty years after their proposal. For the physics topics discussed during this workshop, the application of parity violation has become a standard work horse allowing for the extraction of many physics topics in different experiments.
Download or read book Determination of Electron Beam Polarization Using Electron Detector in Compton Polarimeter with Less Than 1 Statistical and Systematic Uncertainty written by and published by . This book was released on 2015 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Q-weak experiment aims to measure the weak charge of proton with a precision of 4.2%. The proposed precision on weak charge required a 2.5% measurement of the parity violating asymmetry in elastic electron - proton scattering. Polarimetry was the largest experimental contribution to this uncertainty and a new Compton polarimeter was installed in Hall C at Jefferson Lab to make the goal achievable. In this polarimeter the electron beam collides with green laser light in a low gain Fabry-Perot Cavity; the scattered electrons are detected in 4 planes of a novel diamond micro strip detector while the back scattered photons are detected in lead tungstate crystals. This diamond micro-strip detector is the first such device to be used as a tracking detector in a nuclear and particle physics experiment. The diamond detectors are read out using custom built electronic modules that include a preamplifier, a pulse shaping amplifier and a discriminator for each detector micro-strip. We use field programmable gate array based general purpose logic modules for event selection and histogramming. Extensive Monte Carlo simulations and data acquisition simulations were performed to estimate the systematic uncertainties. Additionally, the Moller and Compton polarimeters were cross calibrated at low electron beam currents using a series of interleaved measurements. In this dissertation, we describe all the subsystems of the Compton polarimeter with emphasis on the electron detector. We focus on the FPGA based data acquisition system built by the author and the data analysis methods implemented by the author. The simulations of the data acquisition and the polarimeter that helped rigorously establish the systematic uncertainties of the polarimeter are also elaborated, resulting in the first sub 1% measurement of low energy (?1 GeV) electron beam polarization with a Compton electron detector. We have demonstrated that diamond based micro-strip detectors can be used for tracking in a high radiation environment and it has enabled us to achieve the desired precision in the measurement of the electron beam polarization which in turn has allowed the most precise determination of the weak charge of the proton.
Download or read book Compton Scattering Polarimetry for the Determination of the Proton s Weak Charge Through Measurements of the Parity Violating Asymmetry of 1H e E p written by and published by . This book was released on 2016 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. As of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. Its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effective field theory, and that new physics lies at much higher energies. The Qweak Experiment is testing the Electroweak theory of the Standard Model by making a precise determination of the weak charge of the proton (Qpw). Any signs of "new physics" will appear as a deviation to the Standard Model prediction. The weak charge is determined via a precise measurement of the parity-violating asymmetry of the electron-proton interaction via elastic scattering of a longitudinally polarized electron beam of an un-polarized proton target. The experiment required that the electron beam polarization be measured to an absolute uncertainty of 1%. At this level the electron beam polarization was projected to contribute the single largest experimental uncertainty to the parity-violating asymmetry measurement. This dissertation will detail the use of Compton scattering to determine the electron beam polarization via the detection of the scattered photon. I will conclude the remainder of the dissertation with an independent analysis of the blinded Qweak.
Download or read book Determination of Electron Beam Polarization Using Electron Detector in Compton Polarimeter with Less Than 1 Statistical and Systematic Uncertainty written by Amrendra Narayan and published by . This book was released on 2015 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Q-weak experiment aims to measure the weak charge of proton with a precision of 4.2%. The proposed precision on weak charge required a 2.5% measurement of the parity violating asymmetry in elastic electron - proton scattering. Polarimetry was the largest experimental contribution to this uncertainty and a new Compton polarimeter was installed in Hall C at Jefferson Lab to make the goal achievable. In this polarimeter the electron beam collides with green laser light in a low gain Fabry- Perot Cavity; the scattered electrons are detected in 4 planes of a novel diamond micro strip detector while the back scattered photons are detected in lead tungstate crystals. This diamond micro-strip detector is the first such device to be used as a tracking detector in a nuclear and particle physics experiment. The diamond detectors are read out using custom built electronic modules that include a preamplifier, a pulse shaping amplifier and a discriminator for each detector micro-strip. We use field programmable gate array based general purpose logic modules for event selection and histogramming. Extensive Monte Carlo simulations and data acquisition simulations were performed to estimate the systematic uncertainties. Additionally, the Moller and Compton polarimeters were cross calibrated at low electron beam currents using a series of interleaved measurements. In this dissertation, we describe all the subsystems of the Compton polarimeter with emphasis on the electron detector. We focus on the FPGA based data acquisition system built by the author and the data analysis methods implemented by the author. The simulations of the data acquisition and the polarimeter that helped rigorously establish the systematic uncertainties of the polarimeter are also elaborated, resulting in the first sub 1% measurement of low (~1GeV) electron beam polarization with a Compton electron detector. We have demonstrated that diamond based micro-strip detectors can be used for tracking in a high radiation environment and it has enabled us to achieve the desired precision in the measurement of the electron beam polarization which in turn has allowed the most precise determination of the weak charge of the proton.
Download or read book 10th Conference on the Intersections of Particle and Nuclear Physics written by Marvin L. Marshak and published by American Institute of Physics. This book was released on 2010-01-11 with total page 1010 pages. Available in PDF, EPUB and Kindle. Book excerpt: CIPANP 2009 explores areas of common interest between nuclear physicists, high energy (particle) physicists and astrophysicists. These areas range from studies of the strong interactions that bind nuclei together to physics of the very early Universe and include such topics as neutrinos, hadron physics, spin physics, heavy ion physics, QCD and heavy flavor physics. The Conference papers include descriptions of searches for "new physics", phenomena that cannot be accounted for by current theories.
Download or read book Virtual Compton Scattering at Jefferson Lab written by G. Laveissiere and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spin 2004 Proceedings Of The 16th International Spin Physics Symposium And Workshop On Polarized Electron Sources And Polarimeters With Cd rom written by Franco Bradamante and published by World Scientific. This book was released on 2005-08-02 with total page 1065 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume covers the most recent advances in the field of spin physics, including the latest research in high energy and nuclear physics and the study of nuclear spin structure. The comprehensive coverage also includes polarized proton and electron acceleration and storage as well as polarized ion sources and targets. Many significant new results and achievements on the different topics considered at the symposium are presented in this book for the first time.
Download or read book 5 MeV Mott Polarimeter Development at Jefferson Lab written by John Price and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Calibration of the PEPPo Polarimeter for Electrons and Positrons written by and published by . This book was released on 2013 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The PEPPo (Polarized Electrons for Polarized Positrons) experiment at Jefferson Laboratory investigated the polarization transfer from longitudinally polarized electrons to longitudinally polarized positrons, with the aim of developing this technology for a low energy (~MeV) polarized positron source. Polarization of the positrons was measured by means of a Compton transmission polarimeter where incoming positrons transfer their polarization into circularly polarized photons that were subsequently analyzed by a thick polarized iron target. The measurement of the transmitted photon flux with respect to the orientation of the target polarization (+- ) or the helicity (+- ) of the incoming leptons provided the measurement of their polarization. Similar measurements with a known electron beam were also performed for calibration purposes. This presentation will describe the apparatus and calibrations performed at the injector at the Jefferson Laboratory to measure positron polarization in the momentum range 3.2-6.2 MeV/c, specifically to quantify the positron analyzing power from electron experimental data measured over a comparable momentum range.
Download or read book Small angle Rejection and Study of Inelastic Events in the Jefferson Lab Focal Plane Polarimeter microform written by George Dan Zainea and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1998 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small angle Rejection and Study of Inelastic Events in the Jefferson Lab Focal Plane Polarimeter written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 5 MeV Mott Polarimeter Development at Jefferson Lab written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low energy (E{sub k}=100 keV) Mott scattering polarimeters are ill- suited to support operations foreseen for the polarized electron injector at Jefferson Lab. One solution is to measure the polarization at 5 MeV where multiple and plural scattering are unimportant and precision beam monitoring is straightforward. The higher injector beam current offsets the lower cross-sections. Recent improvements in the CEBAF injector polarimeter scattering chamber have improved signal to noise.
Download or read book A Compton Backscattering Polarimeter for Measuring Longitudinal Electron Polarization written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Compton backscattering polarimetry provides a fast measurement of the polarization of an electron beam in a storage ring. Since the method is non-destructive, the polarization of the electrons can be monitored during internal target experiments. At NIKHEF a Compton polarimeter has been constructed to measure the polarization of the longitudinally polarized electrons stored in the AmPS ring. First results obtained with the polarimeter, the first Compton polarimeter to measure the polarization of a stored longitudinally polarized electron beam, are presented in this paper.
Download or read book Intersections of Particle and Nuclear Physics written by Zohreh Parsa and published by American Inst. of Physics. This book was released on 2004-03-09 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this meeting, as with the seven previous conferences in this series, was to bring together particle and nuclear physicists to share scientific reports and discuss areas of research which overlap both their disciplines. Its relevance has steadily grown as the areas of overlap between particle and nuclear physics have increased. In addition, the success of the standard model has provided a common underpinning for both disciplines as well as similar fundamental goals. Indeed, Quantum Chromodynamics (QCD) has proven to be "the" theory of strong interactions. As such, it forms the basis for nuclear physics as well as high energy hadronic interactions. Topics included are: QCD spectroscopy and dynamics, relativistic heavy ions, QCD and nuclear structure, lepton-hadron and hadron-hadron scattering, heavy quark and heavy lepton physics, spin physics, nuclear and particle astrophysics, neutrinos, accelerators, facilities and detectors, as well as tests of fundamental symmetries.
