Conveners
Solid Polarized Targets
- Josh Pierce
Solid Polarized Targets
- Josh Pierce
Solid Polarized Targets
- Christopher Keith (Jefferson Lab)
Solid Polarized Targets
- Josh Pierce
A dynamically polarized target of protons and deuterons in irradiated NH3 and ND3 will be employed with the CLAS12 detector system to explore the spin structure of the nucleon in Hall B at Jefferson Lab. This target will feature a versatile horizontal 1 K refrigerator that has been constructed by a collaboration composed of Christopher Newport University, Old Dominion University, the...
Upcoming spin structure experiments in Hall B at Jefferson Lab will employ a new dynamically polarized target inside the CLAS12 detector system. Protons and deuterons in irradiated NH3 and ND3 will be polarized at 1 K using the 5 T field of the CLAS12 solenoidal magnet. For optimum polarization, the field uniformity requirements are around 100 ppm over the...
Solid polarized targets rely on continuous-wave Nuclear Magnetic Resonance techniques to provide measurements of the enhanced polarization provided under Dynamic Nuclear Polarization. Upcoming polarized target experiments in Jefferson Lab's Hall B present challenging conditions which would benefit from improvements to traditional NMR techniques. For decades, JLab has relied upon Liverpool...
In the $^{139}$La(n,$\gamma$)$^{140}$La reaction, a T-violating asymmetry is expected to be enhanced by about 6 orders of magnitude[1]. NOPTREX (Neutron Optics for Parity and Time Reversal EXperiment) collaboration is planning to search for the T-violation in this reaction, where a polarized target of $^{139}$La nuclear spin is indispensable. Basically, we are keeping two choices, Brute Force...
In this presentation, the design of the polarized target to be used in the SPINQUEST experiment at FermiLab will be discussed. The polarized target, consisting of either NH3 or ND3, is centered in a 5T magnet field and polarized by 140 GHz microwaves. A new NMR system will measure the degree of polarization. The evaporation of the helium surrounding the target, caused by the intense beam of...
The Liverpool Q-meters were developed in the late 70s and became a de facto industry standard for NMR-based polarization measurements of polarized solid targets. However, it is becoming increasingly more difficult to produce the required number of q-meter channels as the components have become obsolete. The Los Alamos National Laboratory (LANL) group has developed a new NMR-based polarization...
The UVA-LANL polarized target system consists of a 5T, split-coil, superconducting magnet and uses a 140 GHz microwave source to provide highly polarized protons and deuterons via dynamic nuclear polarization (DNP). The DNP process leverages the large discrepancy between the electron and proton magnetic moments, along with Zeeman splitting in the magnetic field, and spin-spin coupling to pump...
The SpinQuest experiment at Fermilab aims to measure the Sivers asymmetry for the $\bar{u}$ and $\bar{d}$ sea quarks in the nucleon using the Drell-Yan process. The experiment will use a 5 T magnet, a $^4$He evaporation fridge with a large pumping system and 140 GHz microwaves to produce transversely polarized NH$_3$ and ND$_3$ targets. The proposed beam intensity is 1.5 $\times$ 10$^{12}$ of...
Scattering length neutrons for cold protons remarkably depends on relative direction of their spins. Thus, scattering pattern of polarized neutrons varies as a function of proton-polarization (P$_H$) of samples. This technique called spin-contrast-variation (SCV) enables us to determine detailed structure of composite materials from the P$_H$-dependent multiple scatterings.
Since Stuhrmann...
The spin dependence of the neutron scattering cross section, especially for hydrogen, makes Dynamic Nuclear Polarization a powerful technique for improving neutron diffraction measurements, especially for biological and soft matter systems. Oak Ridge National Laboratory has demonstrated the application of this technique to Neutron Macromolecular Crystallography, with an eye towards DNP become...
The A2-Collaboration at the Mainz Microtron MAMI measures photon absorption cross sections using circularly and linearly polarized 'Bremsstrahlung' photons up to an energy of ~1.5GeV. We use a 4 π detection system with the 'Crystal Ball' as central part.
We have developed a Frozen Spin Target in close collaboration with the polarized target group of the Joint Institute for Nuclear Research in...
In 2018 the COMPASS experiment at CERN applied a transversely solid polarized proton target with a negative pion beam to measure the Sivers asymmetry using Drell-Yan process. The target system consists of a 50 mK dilution refrigerator, a 2.5 T solenoid magnet, two sets of 70 GHz microwave system. Solid NH$_3$ beads of the target material was contained in 2-target-cell of 55-55 cm long with a 4...
Highly-polarized, frozen-spin targets of solid Hydrogen Deuteride (HDice) have been successfully used with photon beam for nuclear physics measurements for over a decade. With Jefferson Lab’s upgrade to 12 GeV, a new effort has begun to expand the physics reach using HDice targets with electron beam. Three “high impact” experiments, which plan to utilize transversely polarized HDice targets...
In this talk I will discuss the dilution refrigerator used in our lab for Polarized Target Physics. Originally constructed at CERN by Niinikoski in the mid 1970’s, modified by the Helmholtz Zentrum Geesthacht laboratory for neutron studies, and finally obtained us at UVA for use in the HIGS collaboration. I will discuss the changes that have been made after we started using it. In November...
A new dynamic nuclear polarization (DNP) target system has recently come on-line at the University of New Hampshire. DNP is driven by a novel solid-state 140 GHz mm-wave source with quasi-optics transmission and low-loss (<0.1 dB/m) overmodal waveguide that is insensitive to magnetic fields. We have also developed a method to 3D print with Kel-F, which was used to produce target material cups...
The UNH nuclear physics group operates a 5 Tesla, 1 Kelvin Dynamic Nuclear Polarization Lab. We have performed enhanced polarization measurements on Butanol, Propanediol, thermosetting polymers and deuterated analogs using commercially available radicals. We will present max polarizations obtained along with polarization relaxation times. We will also discuss a temperature controlled process...
