Conveners
Targets: Parallel I
- Christopher Keith (Jefferson Lab)
Targets: Parallel II
- Andreas Thomas (University Mainz)
Targets: Parallel III
- Gerhard Alois Reicherz (Ruhr-Universitaet Bochum (DE))
Targets: Parallel IV
- Christopher Keith (Jefferson Lab)
Targets: Parallel V
- Jaakko Henrik Koivuniemi (Univ. Illinois at Urbana-Champaign (US))
Targets: Parallel VI
- Thomas Gentile
Targets: Parallel VII
- Matt Poelker
Targets: Parallel VIII
- Joe Grames
Description
Polarized Ion and Lepton Sources and Targets
The 2015 International Workshop on Polarized Sources, Targets & Polarimetry took place at the Ruhr-University Bochum on September 14th - 18th 2015. The Workshop has been a tradition for more than 20 years, moving between Europe, USA and Japan. The XVIth International Workshop on Polarized Sources, Targets and Polarimetry (PSTP 2015) addresses the physics and technological challenges related to...
The large spin dependence of the absorption cross section for neutrons by 3He gas provides a method to polarize neutron beams. For certain applications, such polarized 3He-based neutron ”spin filters” have advantages over conventional neutron optical polarizing methods. Spin filters operate at all neutron wavelengths, can cover a large angular range and/or a large energy range, and decouple...
At Jefferson Lab, a Polarized 3He Target has been used as an effective polarized neutron target for studying nucleon spin structure. For the 12 GeV program at JLab, the first stage upgrade of the target aim to increase factor of three the performance (Figure-of-Merit) and reach a systematic uncertainty of polarimetry below 3%. During the 6 GeV era, the target polarization was measured by two...
The Bochum polarized target group is involved in the fixed target experiments COMPASS at CERN and baryon spectroscopy at ELSA and MAMI. The experiments at Bonn and Mainz are focused on the study of the nucleon resonance region with polarized beam and target with 4 detection system. The focus of the COMPASS experiment is the study of hadron structure and hadron spectroscopy with high intensity...
Most of the activity in the Polarized Target Lab. at the University of Virginia has centered around the preparation of polarized targets for experiments at Fermilab and TUNL(Duke U.), while investigating some special features for experiments at JLab. For experiment E1039 at Fermilab a magnet/ 4He refrigerator combination that had been in storage for 15 years has been modified and restored to...
A discussion of dynamic orientation using optimized radio frequency (RF) irradiation produced perpendicular to the holding field is presented for the spin-1 system required for tensor polarized fixed target experiments. The rate equations are solved numerically to study a semi-saturated steady-state resulting from the two sources of irradiation, microwave from the DNP process and the...
The University of Virginia (UVA) polarized target group in cooperation with Los Alamos National Lab has designed and built a solid polarized target system for the anticipated Fermilab E1039 Drell-Yan experiment. We report the completion of refurbishing the 5T superconducting Oxford magnet and 1K evaporation refrigerator. Recent tests performed at UVA will be presented.
With Jefferson Lab’s upgrade to a 12 GeV electron beam comes a new, improved detector system in Hall B: CLAS12. The dynamically polarized solid target, which was a mainstay of double-polarized scattering experiments in the 6 GeV era, must also be rebuilt to accommodate the new constraints. The new target and its horizontal refrigerator will fit in a space restricted by the new CLAS12 5 T...
The HDice frozen spin, solid Hydrogen-Deuteride target has been used in recent years with photon beams in Jefferson Lab’s Hall B. With the recent upgrade of the Hall’s CLAS detector and Jefferson Lab’s CEBAF accelerator come new physics opportunities to study the 3D structure of the nucleon. In this vein, there are presently three A-rated experiments which have been designated as having a...
Three A-rated proposals to study the 3D structure of the nucleon with the CLAS12 detector require a transversely polarized target [1]. A minimal R B × dL is needed to limit beam deflection by the transverse holding field of such a target. At the same time, the axial field of the CLAS12 central solenoid must be canceled over the same region. Finally, adequate field uniformity to allow NMR...
In scattering experiments that use targets relying on dynamic nuclear polarization (DNP), target materials must be irradiated using microwaves at a frequency determined by the difference in the nuclear Larmor and electron paramagnetic resonance (EPR) frequencies. Since the resonance frequency changes with time as a result of radiation damage, the microwave frequency should be adjusted...
The Dynamic Nuclear Polarization (DNP) is an efficient technique to enhance the nucleus polarization by the so-called ‘Radiation doping’ or ‘Radical chemically doping’ methods in the field of polarized solid targets for their use in nuclear and particle physics experiments. Polymer materials have been used since 1994 due to the advantage of its easy handling at room temperature and shape...
In the polarized Drell–Yan experiment at the COMPASS facility in CERN a pion beam with momentum of 190 GeV/c and intensity about 108 pions/s interacted with transversely polarized proton target. The muon pair produced in Drell–Yan process was detected. The measurement was done in 2015 as the 1st ever polarized Drell–Yan experiment. The solid-state NH3 as polarized proton target was polarized...
A COMPASS (Common Muon Proton Apparatus for Structure and Spectroscopy) group researches hadron structure and hadron spectroscopy with high intensity muon and hadron beams. In 2015, COMPASS performed a polarized DY experiment to measure transverse momentum dependent parton distributions. A π− beam with momentum 190 GeV/c and a transversely polarized proton target (PT) were used.
The COMPASS...
The Collaboration measures the integrand of the GDH integral for the deuteron
below 20 MeV. Mono-energetic and polarized intensive gamma rays produced by
HIγS at Duke Free Electron Laser Laboratory are incident on longitudinally
polarized deuteron target, using HIFROST. Neutrons from photodisintegration
reaction on...
Polarized 3He gas targets have been used successfully at Jefferson Lab (JLab) for a number of electron scattering experiments to study 3He spin physics and more importantly, as an effective polarized neutron target, to study the neutron spin physics, including longitudinal and transverse spin structure and 3-d structure. The performance of the JLab target reached...
In the main frame of the experiment programs on COSY ring, more precise measurements
on spin dependent cross sections for the spin filtering process (PAX experiment)
and on the Time Reversal Invariance test at COSY (TRIC), required the upgrading of
the gaseous internal polarized target and the whole system of it: the pABS (polarized
atomic beam source), the cell (openable) and the diagnostics...
In the Spallation Neutron Source based neutron Electric Dipole Moment (SNS nEDM)
experiment, spins of polarized ultracold neutrons and polarized 3He will be manipulated in
a 0.3 - 0.5 K superfluid 4He bath. Measurements will be made using two different modes:
free precession and critical dressed spin. In the former, both spin species undergo a π/2
flip and then precess at their Larmor...
Photocathodes with higher polarization and quantum efficiency (QE) can significantly enhance
the physics capabilities of electron accelerators. In this submission, we describe the characteristics
of strained GaAs/GaAsP superlattice photocathodes fabricated with a Distributed Bragg Reflector
(DBR). The distributed Bragg reflector (DBR) concept was proposed to enhance the QE...
Hydrogen and deuterium exists as two spin isomers, ortho and para, with the nuclear magnetic moments of the atoms either parallel or antiparallel. The spatial separation of the orthohydrogen molecules with respect to their nuclear moment in strongly inhomogeneous field of superconducting sextupole magnets is described. The scheme of the experimental setup and the results obtained under the...
Electron vortex beams provides an entirely new and unexplored degree of freedom for use in nuclear and particle physics- namely quantized orbital angular momentum (OAM). For example it may be used to explore the fundamental question of the contribution of of the orbital angular momentum of quarks and gluons to the spin of the proton. Such a source is under development at Jefferson Lab....
An optical vortex forming a helical wave front along the direction of propagation of the beam has been actively investigated over the past few decades. Such vortices possess a phase singularity at the center of the beam, and the field strength there is zero. More importantly, it has been shown that an optical vortex which possesses a phase term exp(imφ) carries discrete values mħ of orbital...
In order to construct a future electron ion collider with high luminosity, a high average current and high bunch charge polarized electron source is under R&D at Brookhaven National Laboratory. A prototype of a high average current polarized electron funneling gun as an eRHIC injector has been built and in testing in Stonybrook University. Recently,...
