Search

Apart from their very classical use to build polarized targets for particle physics, the methods of dynamic nuclear polarization (DNP) have more recently found application for sensitivity enhancement in high-resolution NMR, both in the solid and in the liquid state. It is often thought that the possible signal enhancement in such applications deteriorates when the DNP is performed at higher fields. We show that for a dissolution-DNP method that uses conventional (2,2,6,6-tetramethylpiperidine 1-oxyl) radicals as the paramagnetic agent, this is not the case for fields up to 5 T. [ABSTRACT FROM AUTHOR]

We study squeezing of the spin uncertainties by quantum nondemolition (QND) measurement in non-polarized spin ensembles. Unlike the case of polarized ensembles, the QND measurements can be performed with negligible back-action, which allows, in principle, perfect spin squeezing as quantified by Tóth et al (2007 Phys. Rev. Lett. 99 250405). The generated spin states approach many-body singlet states and contain a macroscopic number of entangled particles even when individual spin is large. We introduce the Gaussian treatment of unpolarized spin states and use it to estimate the achievable spin squeezing for realistic experimental parameters. Our proposal might have applications for magnetometry with a high spatial resolution or quantum memories storing information in decoherence free subspaces. [ABSTRACT FROM AUTHOR]

The standard theoretical description of Polarized DIS is based on the use of the DGLAP evolution equations. This approach controls the Q2 -evolution of the DIS structure functions but cannot describe the x -evolution and therefore should not be used at small x. We complement this approach, accounting for the x-evolution of the spin structure function g1 in the leading logarithmic approximation. [ABSTRACT FROM AUTHOR]

A first storage cell for the Polarized Internal gas Target (PIT) of the ANKE facility at COSY was produced from a Teflon-coated pure Aluminum foil and successfully used in the double polarized experiment with a 1.2 GeV polarized deuteron beam carried out at the COSY accelerator in January 2007. Prior to this experiment, the minimum possible cross section of the storage-cell beam tube at the interaction point at ANKE was determined, based on the COSY beam profile at different beam formation stages. Electron cooling combined with stacking and stochastic cooling have been studied as well. Experiments with N2 gas in the storage cell to simulate the background produced by beam interaction with the aluminum cell walls were performed. The analysis of the $\vec d\vec p \to {{dp}}$ and $\vec d\vec p \to (dp_{sp})\pi^0$ reactions showed that events from the extended target can be clearly identified in the ANKE detector system. Taking into account the known intensity of the Atomic Beam Source (ABS), the expected target density in the experiment with a storage-cell beam tube of 15hor × 20vert × 390long mm3 and a 130 mm long feeding tube with 15 mm diameter reach values of 3.2 × 1013 at/cm2. The polarization, measured by the np → dπ0 reaction with the storage-cell, was 0.75 ± 0.06. [ABSTRACT FROM AUTHOR]

The article provides information on a method devised by researchers at the University of California in Berkeley to polarize the nuclei in a material. The standard approach is to apply a static magnetic field in the desired direction. The new method is to apply a rotating field and induce magnetization in the direction of the rotation axis. One of the people involved in the earliest experiments on electron spins in rotating fields, Erwin Hahn.

It is shown that the spin asymmetry in the reaction π–p → a00(980)n → (ηπ0)S n is highly sensitive to the mixing of the a00(980) and f0(980) resonances. At low momentum transfers (namely, in any of the intervals 0 ≤ –t ≤ 0.025, ..., 0.1 GeV2), the asymmetry normalized in such a way that it takes values between –1 and 1 must undergo a jump close in magnitude to unity in the region of the ηπ0 invariant masses between 0.965 and 1.01 GeV. A large jump of the asymmetry is due exclusively to a00(980) – f0(980) mixing. A very high resolution in the ηπ0 invariant mass is not required for observing the jump of the asymmetry. The energy dependence of the polarization effect is expected to be rather weak; therefore, the polarization effect in question can be studied at any high energy—for example, in the range between 8 and 100 GeV.© 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

An experimental program has been started at MAMI and ELSA to measure the integrand of the Gerasimov–Drell–Hearn sum rule (GDH) in a photon energy range starting from the pion threshold up to 2.9 GeV. A polarized target has been built, which is based on the frozen spin technique. Since the value of the nucleon polarization and the areal density of the target contribute directly to the result of the GDH-integral both quantities have to be determined with high accuracy. [Copyright &y& Elsevier]

Here we will give an overview of the developments in cryogenic and magnet technology used in polarized targets from the roots to nowadays and a brief outlook on new concepts of the polarized target technology for future polarized nuclear and particle physics experiments. [Copyright &y& Elsevier]