Search

In this paper the method of beam depolarization compensation during spin resonance crossing is developed. This method is based on the restoration of the spin adiabatic invariant after the spin resonance crossing. The case when the restoration of spin adiabatic invariant occurs due to multiple crossing of the resonance effective area is considered. At the same time it is necessary to provide the certain difference of spin phases between the moments of crossing of the resonance effective area. The conditions of beam polarization preservation when the resonance effective area is repeatedly crossed are obtained. Numerical examples are presented. [ABSTRACT FROM AUTHOR]

Laudatio in honor of Dr. Miguel Ángel Pérez Angón, co-recipient of the 2008 Medal of the Division of Particles and Fields of the Mexican Physical Society [ABSTRACT FROM AUTHOR]

The simulation of PIXE (Particle Induced X-ray Emission) is discussed in the context of general-purpose Monte Carlo systems for particle transport. Dedicated PIXE codes are mainly concerned with the application of the technique to elemental analysis, but they lack the capability of dealing with complex experimental configurations. General-purpose Monte Carlo codes provide powerful tools to model the experimental environment in great detail, but so far they have provided limited functionality for PIXE simulation. This paper reviews recent developments that have endowed the Geant4 simulation toolkit with advanced capabilities for PIXE simulation, and related efforts for quantitative validation of cross sections and other physical parameters relevant to PIXE simulation. [ABSTRACT FROM AUTHOR]

This paper is a brief historical review of the quest to find neutrinos of extraterrestrial origin. In the context of the Victor Hess centenary, it is interesting to consider how the development of detectors for neutrinos from space relates to developments in cosmic-ray and particle physics over the same time span. [ABSTRACT FROM AUTHOR]

The initial commissioning of the beam line for the T2K long baseline neutrino experiment was carried out in April and May of 2009. This paper contains an overview of the beam line components and presents initial results from the beam line commissioning. [ABSTRACT FROM AUTHOR]

One of the main goals of the Tevatron RunII is to look for any hints for new physics. At D0, the range of searches for new physics signals is large. A few of these analyzes are discussed in this paper. [ABSTRACT FROM AUTHOR]

It is still a mystery why the Standard Model as we know it has only three families. At new high energy colliders it is worthwhile to search for a new additional family which obviously would have a heavy neutrino to avoid the LEP bounds. This paper discusses new studies made with the CMS detector for the search of new heavy b-like quarks in several different decay modes and for different possible mass regions. These studies are based on detailed detector simulation, including all Standard Model backgrounds. Particular emphasis is given to possible early discoveries, i.e. with 100 pb-1 or less. Projected 95% CL exclusion limits as a function of luminosity are presented as well. [ABSTRACT FROM AUTHOR]

A green laser (CW, 532 nm) based Fabry-Pérot cavity for high precision Compton Polarimetry is under development in Hall A of the Jefferson Laboratory. In this paper, we present the principle and the preliminary studies for our test cavity. [ABSTRACT FROM AUTHOR]

In a circular accelerator, exciting a coherent spin precession can be used to measure the spin precession tune, which is critical for understanding spin dynamics of the polarized beam. This can be achieved by driving the polarized beam with an rf dipole at an oscillating frequency fres in the vicinity of the beam spin precession frequency fs, namely, fres≈fs. The driven coherent spin precession was measured with the RHIC Coulomb Nuclear Interference polarimeter using a carbon target. This paper presents the spin coherent precession observed with polarized proton beam at the BNL RHIC. Both experimental data and its application for spin tune measurement are discussed. [ABSTRACT FROM AUTHOR]

This paper describes the characteristics of the multihole collimator gamma camera that is simulated using the combination of the Monte Carlo N-Particles Code (MCNP) version 5 and in-house software. The model is constructed based on the GCA-7100A Toshiba Gamma Camera at the Royal Surrey County Hospital, Guildford, Surrey, UK. The characteristics are analyzed based on the spatial resolution of the images detected by the Sodium Iodide (NaI) detector. The result is recorded in a list-mode file referred to as a PTRAC file within MCNP5. All pertinent nuclear reaction mechanisms, such as Compton and Rayleigh scattering and photoelectric absorption are undertaken by MCNP5 for all materials encountered by each photon. The experiments were conducted on Tl-201, Co-57, Tc-99 m and Cr-51 radio nuclides. The comparison of full width half maximum value of each datasets obtained from experimental work, simulation and literature are also reported in this paper. The relationship of the simulated data is in agreement with the experimental results and data obtained in the literature. A careful inspection at each of the data points of the spatial resolution of Tc-99 m shows a slight discrepancy between these sets. However, the difference is very insignificant, i.e. less than 3 mm only, which corresponds to a size of less than 1 pixel only (of the segmented detector). [ABSTRACT FROM AUTHOR]

NLO QCD analysis of the world unpolarized and polarized deep-inelastic experimental data were performed in order to extract the ΛQCD and αs(Mz2). In this paper we use the ΛQCD which can be obtain from the polarized deeply inelastic scattering. By having the ΛQCD, one can determine the αs(Mz2). We compare all of different NLO measurements of the strong coupling constant in unpolarized and polarized deeply inelastic scattering. [ABSTRACT FROM AUTHOR]

Fission measurements have a long history at Los Alamos. This paper reviews the current programs in neutron-induced fission at the Los Alamos Neutron Science Center. [ABSTRACT FROM AUTHOR]

Large production of the cc pairs and high integrated luminosity make the PEP-II B Factory an excellent place for studying the charm hadrons. In this paper, we present a few of the most recent results from the BABAR collaboration in the charm sector. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

High-precision data in three-nucleon scattering processes and state-of-the-art few-body calculations have contributed significantly to our present understanding of three-nucleon forces at intermediate energies. This paper discusses in more detail the pd→3Heγ reaction as a probe for electromagnetic currents in the three-nucleon system. Experimental data are reviewed and interpreted by a comparison with Faddeev and coupled-channel calculations from the Bochum-Cracow and Hanover theory groups, respectively. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We propose and find pulse sequences for non-adiabatic two-qubit gates (CNOT, swap and controlled Z gates) for the Kane silicon-based electron mediated nuclear spin quantum computer architecture. These quantum gates are simpler, with higher fidelity and faster than existing proposals. Any two qubit gate may be implemented using similar pulse sequences. In this paper, we investigate the effect of decoherence on the operation of these quantum gates and some simple algorithms for a variety of dephasing rates. Our model shows that conservative estimates of the dephasing rates in the Kane architecture give gate fidelities comparable to that required for fault tolerant quantum computing. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A major difficulty in realising a solid-state quantum computer is to reliably readout its qubit state at the end of computation. In this paper, we propose an efficient readout scheme making use of the resonance tunneling of a ballistic electron produced by a single electron pump. The resonance condition is perturbed when a charge qubit is placed nearby and consequently the transmission property of the ancillary readout electron reflects the qubit state to be measured. A fully quantum dynamical model for the readout of solid-state charge qubits is presented, which allows us to examine in detail the coherent evolution of the ancillary electron and the qubit system. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper we show how effective parameters such as effective binding energies can be defined for a proton in the combined nuclear-Coulomb potential, including also the target potential, in the case in which the proton is bound in a nucleus which is partner of a nuclear reaction. Using such effective parameters the proton behaves similarly to a neutron. In this way some unexpected results obtained from dynamical calculations for reactions initiated by very weakly bound proton halo nuclei can be interpreted. Namely the fact that stripping dominates the nuclear breakup cross section which in turn dominates over the Coulomb breakup even when the target is heavy at medium to high incident energies. Our interpretation helps also clarifying why the existence and characteristics of a proton halo extracted from different types of data have sometimes appeared contradictory. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A possible issue to the nuclear waste problem is the transmutation of the long-lived radiotoxic components of the spent fuel. The development of subcritical systems with an external neutron source, provided by a high-energy proton beam impinging onto a spallation target are of special interest in this context. This paper describes the accelerator for such an Accelerator Driven System (ADS), studied within the European PDS-XADS programme. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper a new method is presented for particles in storage rings which could reach a statistical sensitivity of 10-27 e·cm for the deuteron EDM. This implies an improvement of two orders of magnitude over the present best limits on the T-odd nuclear forces ξ parameter. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Photomultiplier Tubes are devices designed to amplify very small light signals, on the order of single photons, to levels that are detectable by conventional electronics. Such a high level of amplification, however, comes with a quite a few potential problems, as the relationship between a light signal in and the current out- the response of the system- can be difficult to determine, meaning that photomultiplier tubes’ use in scientific research requires a great deal of sensitive calibration. Once calibrated, the photomultiplier tube is a tool that can be used on a number of interesting problems, including the field of neutrino physics. This work deals with the use of photomultiplier tubes’ use in the upcoming Double Chooz experiment to determine the mixing angle θ13, between different neutrino mass eigenstates. Calibration of the tubes requires measurement of the charge characteristics, most notably, the gain, pedestal, and the dark rate of a tube. Moreover, for all modern tubes, there is an additional feature which can be used to calibrate the system, the single photo electron peak, which describes the response of the tube to a single photon. Some theories predict higher order effects, in addition to the single photoelectron peak, including things like incomplete multiplication of a single photon electron, features which are theoretically able to be determined by a detailed examination of the single photoelectron peak. This paper goes through the methods of calibrating a phototubes both with and without a single photoelectron peak, and is unable to determine conclusively whether or not partial multiplication is able to explain certain features of photomultiplier tubes with a single photoelectron peak. [ABSTRACT FROM AUTHOR]

In this paper we give a brief description of diffractive processes. We focus on ep collisions at HERA and outline key features of exclusive diffraction in hadron-hadron collision. We discuss respectively: diffractive parton distributions of the proton obtained from DGLAP fits to HERA data, including the twist-4 contribution, afterwards diffractive charm production from dipole model and at the end shortly exclusive production of a Higgs boson in pp scattering. [ABSTRACT FROM AUTHOR]

Most simulations of intense particle beams are performed nowadays using Particle In Cell (PIC) techniques. Direct grid based Vlasov methods have also been used but mostly for 1D simulations as they become very costly in higher dimensions when using uniform phase space grids. We have recently introduced adaptive mesh refinement techniques that allow us to automatically concentrate the grid points at places where the distribution function is varying most. In this paper we shall introduce this technique and show how it can be used to improve the efficiency of grid based Vlasov solvers. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper is based on recently described sets of self-consistent 2D and 3D time-dependent space charge distributions. A subset of these distributions can be injection-painted into an accumulator ring, such as the Spallation Neutron Source Ring, to produce periodic space charge conditions. The periodic condition guarantees zero space-charge-induced halo growth and beam loss during injection. Also, some of these distributions can be manipulated to produce flat, or even point-like, beams. Practical aspects of such schemes are discussed, and simulations of a number of 2D and 3D specific cases are presented. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Elemental characterization of low Z elements (C,H,Cl,Fe) inside bulk materials were performed using PGNAA technique. Samples having elemental composition similar to explosives were used for such experimentations using moderated DD neutrons as well as DT(14MeV) neutrons. We could observe characteristic prompt capture gamma rays of hydrogen (2.224MeV), nitrogen (10.83 MeV), chlorine (6.11 MeV) and Fe (6.02MeV and 7.63MeV) also (n,n'γ) prompt gamma signal (4.43MeV) of carbon. BGO detector has been used for gamma spectrum acquisition. These experimentations has been carried out for initial feasibility studies of detecting prompt gamma lines as a part of PGNAA technique based explosive detection system development. A detail description of experimental set up and procedure has been discussed in paper. [ABSTRACT FROM AUTHOR]

The modification of particle distributions by magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Even low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Particle distributions can be modified only by the existence of resonances, the locations of which depend on particle energy, equilibrium parameters, and mode shape and frequency. Flattening of a distribution due to phase mixing in an island or due to portions of phase space becoming stochastic is a process extremely rapid on the time scale of an experiment but still very long compared to the time scale of guiding center simulations. In this paper we discuss the interaction between a given spectrum of modes and a high energy particle distribution. [ABSTRACT FROM AUTHOR]

The behavior of energetic particle driven modes in magnetically confined plasmas is an important issue for ITER, once these modes can affect the transport of the fast particles. This paper presents some data analysis methods suitable for dealing with these modes. These methods are exemplified through the characterization of electron fishbones and Beta-induced Alfvén Eigenmodes instabilities in the tokamaks Tore Supra and FTU. [ABSTRACT FROM AUTHOR]

Progress in particle and nuclear physics has been closely connected to the progress in accelerator technologies - a connection that is highly beneficial to both fields. This paper presents a review of the present and future facilities and accelerator technologies that will push the frontiers of high-energy particle interactions and high intensity secondary particle beams. [ABSTRACT FROM AUTHOR]

In the present work, a statistical approach is proposed for modeling of processes in equipments of enrichment and separation of mineral resources, i.e. when determining a particle location probability, the Gibbs method is used. A set of states of noninteracting particles is taken as a statistical ensemble. Knowing initial conditions, laws of motion and trajectories of noninteracting particles, one can determine a concentration of all possible positions of the particle in the equipment at subsequent moments of time. In a stationary case, a definite time-independent distribution of a density of "possible" particles on a working surface is obtained. According to the Gibbs method, this distribution is identified with the probability distribution of the location of one particle. As an example, the modeling of the processes in an air spiral separator is presented. A developed algorithm of determination of the particle position probability on the working surface of the air separator can be used as an element of a more complex mathematical model, for example, the one where interactions between the particles are taken into account. [ABSTRACT FROM AUTHOR]

Hadron spectroscopy has been an essential part of the physics program with the CLAS detector in experimental Hall B at Jefferson Lab. Production of baryon and meson resonances with high energy (polarized) electron and photon beams was studied on a veriety of targets, ranging from hydrogen to lead. Physics topics of interest include: investigation of the spectrum of baryon and meson resonances, transition form-factors, meson-nucleon couplings (mesons in nuclei), and search for exotic and missing states. With the 12 GeV upgrade of the CEBAF machine, hadron spectroscopy in Hall B will be extended to a new domain of higher mass resonances and the range of higher transferred momentum using up to 11 GeV electron beams and the upgraded CLAS12 detector. In this paper a brief description of the CLAS12 detector and the physics program adopted for 12 GeV with emphasis to baryon and meson spectroscopy is presented. [ABSTRACT FROM AUTHOR]

The electromagnetic form factors of nucleons are fundamental quantities in nucleon structure. As such, they have been studied extensively both theoretically and experimentally. Significant progress has been made with new measurements at Jlab, MAMI and MIT-Bates, with emphases on expanding the momentum-transfer range and on higher precision. In this paper, we describe the status of this field and present new results from measurements at both low and high momentum transfers. We also compare the experimental data to model predictions, and mention possible implications of the new results to other fields. [ABSTRACT FROM AUTHOR]

In this talk I discuss the nucleon pair approximation of the shell model based our recent results, including the microscopic foundation and its applications to realistic nuclei. [ABSTRACT FROM AUTHOR]

This paper presents the observation of the electroweak production of single top quarks in the D0 detector at the Fermilab Tevatron pp Collider at a center-of-mass energy of 1.96 TeV. Events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks are used to measure a cross section for single top-quark production of σ(pp→tb+X,tqb+X) = 3.94±0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5×10-7, corresponding to a 5.0 standard deviation significance. [ABSTRACT FROM AUTHOR]

Several Standard Model processes contain electrons in the final state. Also, many signatures expected from physics beyond the Standard Model include one or more electrons. This paper describes the electron reconstruction along with some of the identification criteria used in the ATLAS detector. The expected performance at the start-up of the experiment are also presented. [ABSTRACT FROM AUTHOR]

In this paper we briefly discuss the estimation of uncertainties in QCD backgrounds to searches for Supersymmetry under development by the ATLAS collaboration. [ABSTRACT FROM AUTHOR]

The performance of the ALICE detector in searches for new heavy stable charged particles in pp collisions is discussed in this paper. Gluino R-hadron was chosen as an example of a candidate, and cross sections and kinematic properties were obtained from PYTHIA simulations for various gluino masses (100–500 GeV/c2). Detector response simulations for R-hadrons in the TPC acceptance (|η|<1) were performed for 100 GeV/c2 R-hadron mass. [ABSTRACT FROM AUTHOR]

In this paper an updated GEANT-4 simulation toolkit is presented describing the interactions in matter of heavy hadrons containing long-lived squarks and gluinos. Generic signatures are derived that are applicable at the Large Hadron Collider, and the problem of theoretical uncertainties arising from model dependence is addressed. For a more detailed description of the assumptions and techniques used, the reader is referred to ref. [1]. [ABSTRACT FROM AUTHOR]

We describe plans for a search for long-lived particles which will become stopped by the CMS detector. We will look for the subsequent decay of these particles during time intervals where there are no pp collisions in CMS: during gaps between crossings in the LHC beam structure, and during inter-fill periods between the beam being dumped and re-injection. Such long living particles decays will be recorded with dedicated calorimeter triggers. For models predicting these particles, such as split-susy gluinos, the large cross-section combined with good stopping power of CMS, yields a significant number of triggerable decays. If LHC instantaneous luminosity approaches 1032 cm-2s-1 in 2009–10, 5σ significance can be established in a matter of days, since these decays occur on top of a negligible background. Due to limited size, this paper concentrates on main idea and expected results. More details are available in https://twiki.cern.ch/twiki/bin/view/CMS/PhysicsResults. [ABSTRACT FROM AUTHOR]

Long-lived charged particles are predicted by many models of physics beyond the Standard Model (SM). At the LHC, the common signature would be a heavy long-lived charged particle with velocity smaller than the speed of light, β<1. This paper presents methods we developed for identifying slow particles and measuring their mass using the ATLAS muon spectrometer. The efficacy of these methods is demonstrated using two different models. [ABSTRACT FROM AUTHOR]

The HIγS facility is capable of providing intense beams of linearly and circularly polarized gamma rays, at energies from 2 MeV and soon to extend up to 100 MeV. This paper describes a Compton scattering program which has been designed to measure the electric and magnetic polarizabilities of the proton and the neutron, as well as the spin-polarizabilities of both. Linearly polarized beams will be used to measure the electric and magnetic polarizabilities of the proton, while Compton scattering from the deuteron will lead to values of these fundamental quantities for the neutron. Circularly polarized beams and polarized proton and 3He targets will be used to extract the four spin-polarizabilities of the nucleons with accuracies ranging from 5-to-25%. These values will be compared to the predictions of Chiral Perturbation Theory and anticipated results from Lattice QCD calculations. [ABSTRACT FROM AUTHOR]

In this paper a concise overview of recent results concerning the properties of ion-particle interaction and the ion drag force in complex (dusty) plasmas is presented. Two main theoretical approaches to calculate the ion drag force—binary collision and linear plasma response formalisms are discussed. When possible, theoretical results are compared with the results from experiments and numerical simulations. [ABSTRACT FROM AUTHOR]

In spite of the huge amount of fission yield data available in different libraries, more accurate values are still needed for nuclear energy applications and to improve our understanding of the fission process. Thus measurements of fission yields were performed at the mass spectrometer Lohengrin at the Institut Laue-Langevin in Grenoble, France. The mass separator Lohengrin is situated at the research reactor of the institute and permits the placement of an actinide layer in a high thermal neutron flux. It separates fragments according to their atomic mass, kinetic energy and ionic charge state by the action of magnetic and electric fields. Coupled to a high resolution ionization chamber the experiment was used to investigate the mass and isotopic yields in the light mass region. Almost all fission yields of isotopes from Th to Cf have been measured at Lohengrin with this method. It has been extended in this work to the heavy mass region for the reactions 235U(nth,f), 239Pu(nth,f), and 241Pu(nth,f). For these higher masses an isotopic separation is no longer possible. So, a new method was undertaken with the reaction 239Pu(nth,f) to determine the isotopic yields by γ spectrometry. The results are presented in this paper. [ABSTRACT FROM AUTHOR]

On the base of modified trajectory calculations the shift of angular distribution of α-particles accompanied the reaction 235U(n,f) induced by cold polarized neutrons is evaluated. It was supposed that angular distribution shift is caused by the rotation of nuclear system before scission. The orientation of a rotation motion is determined by the neutron spin polarization along and opposite to the beam direction. For the first time the estimation was done in the frame of trajectory calculations assuming the rotation motion of scissioning nucleus [1]. The result of the calculation is in a good agreement with experimental data of paper [2], where this new phenomenon was named as ROT-effect. [ABSTRACT FROM AUTHOR]

The general framework of constructing trigonometrically fitted Runge-Kutta methods based on the approach introduced by Simos [8] is presented in this paper. Methods of high exponetial order are constructed and tested on the numerical solution of the Schrodinger equation. [ABSTRACT FROM AUTHOR]

The ERLP energy recovery linac prototype at Daresbury Laboratory has been rebranded, and is now called ALICE (Accelerators and Lasers In Combined Experiments). This paper gives an overview of the project and its status, outlines some of the challenges experienced during the commissioning of the photoinjector and superconducting accelerating systems, and presents our photoinjector gun commissioning results. An outline is given of the planned photon science program for ALICE, and its under-pinning role in the EMMA NS-FFAG project. [ABSTRACT FROM AUTHOR]

ALICE—Accelerators and Lasers in Combined Experiments—is a relatively new accelerator built at Daresbury Laboratory that will demonstrate the process of energy recovery by the end of 2008. The project is a research facility to develop the technology required to build a New Light Source (NLS) in the UK. This paper details the current ALICE photoinjector design and highlights the limitations before focusing on a photoinjector upgrade. The key component of the upgrade is a three-stage extreme high vacuum load-lock system that will be incorporated into the ALICE photoinjector in 2010. The load-lock system has de facto become a standard component of a type III–V semiconductor photocathode injector and comprises: 1) loading chamber to allow new photocathodes to be introduced, 2) cleaning chamber for atomic hydrogen cleaning of the photocathodes and, 3) a preparation and activation chamber where the photocathodes will be activated to the NEA state ready for use on the ALICE accelerator. Once commissioned the load-lock system will allow rapid transfer of photocathodes between the load-lock system and the ALICE photoinjector whilst maintaining the integrity of the vacuum system and providing many other benefits. The new load-lock system will not only remove the problems with the existing set-up, it will also permit a new vacuum chamber to be designed for the gun itself. This new design will also aim to improve vacuum performance by addressing some of the major vacuum associated problems ALICE has encountered in the past 2 years. [ABSTRACT FROM AUTHOR]

Generalised Parton Distributions (GPDs) have grown into one of the main topics in hadron physics. They are playing a central role in the physics of the JLab 12 GeV upgrade as well as in the future physics programme of the COMPASS experiment at CERN. This paper explores the future of GPD measurements in the short, medium and long term. The short term includes the analysis of already existing data from HERMES and JLab and planned measurements at JLab before the 12 GeV upgrade. In the medium term this concerns the JLab programme after the upgrade, measurements at COMPASS and at PANDA/FAIR. The EIC project or possible alternatives form the long term perspective. The main focus of the considerations lies on DVCS measurements and related experiments. [ABSTRACT FROM AUTHOR]

The RHIC polarized proton collider polarimeters employ the analyzing power in p-Carbon elastic scattering in the Coulomb Nuclear Interference region to measure the proton beam polarization. These are calibrated by the polarized hydrogen jet target that measures the absolute beam polarization utilizing the pp elastic scattering process in the CNI region. This paper describes the status of these polarimeters and the efforts employed to improve the performance in terms of better resolution, rate handling capability, and reduced systematic uncertainties. [ABSTRACT FROM AUTHOR]

A unique design feature of a polarized Electron-Ion Collider (ELIC) based on CEBAF is its Figure-8 shaped storage rings for both electrons and ions, which significantly simplifies beam polarization maintenance and manipulation. The CEBAF accelerator is used as a full energy injector of polarized electron beams into the electron storage ring. While electron polarization is maintained vertical in arcs of the ring, a stable longitudinal spin at four collision points is achieved through vertical crossing bending magnets, solenoid spin rotators, and horizontal orbit bends. Spin matching technique needs to be implemented in order to enhance quantum self-polarization and minimize depolarization effects. In this paper, we also discuss several important issues related to the use of positron beams, radiative polarization and quantum depolarization effects, as well as spin in ELIC. [ABSTRACT FROM AUTHOR]

Even though RHIC has two full Siberian snakes in each ring, there are various perturbations to the ideal case including orbit errors at the snakes, experiment solenoids, injection bumps, and interlaced horizontal-vertical bumps at the hydrogen jet polarimeter. These errors can cause depolarization by shifting the spin tune and tilting the stable spin direction away from vertical. Tilting of the stable spin axis can enhance horizontal depolarizing resonances. This paper presents preliminary results for some of these error scenarios, as well as their impact on the stable spin directions at STAR and PHENIX. [ABSTRACT FROM AUTHOR]

A dual partial snake scheme has been used for AGS polarized proton operation for several years. It has provided polarized proton beams with 1.5×1011 protons per bunch and 65% polarization for the RHIC spin program. There is still residual polarization loss due to both snake resonances and horizontal resonances as shown in the data. Several schemes were tested or proposed in the AGS to mitigate the loss, such as putting horizontal tune into the spin tune gap, injection into a accelerating bucket, and tune jump across the horizontal resonances. This paper presents the experiment and simulation results and analyses. [ABSTRACT FROM AUTHOR]