A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by ν(s)=γG (γ is the ...Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently precess at a frequency of ≈120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10^{-8}, and to 1×10^{-10} for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97 GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron ...(COSY) storage ring in order to control both the precession rate (≈121 kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of σ=0.21 rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.
The Jülich Electric Dipole moment Investigation (JEDI) Collaboration works on a measurement of the electric dipole moment (EDM) of charged hadrons using a storage ring. Such a dipole moment would ...violate
C
P
symmetry, providing a possible option for physics beyond the Standard Model. The JEDI experiment requires a small beam orbit root mean square (RMS) in order to control systematic uncertainties. Therefore an ongoing upgrade of the Cooler Synchrotron (COSY) at Forschungszentrum Jülich is done in order to improve the precision of the beam position. The first results of the beam based alignment method, that was tested with one quadrupole in the ring, will be discussed.
The JEDI (Jülich Electric Dipole Investigations) (
http://collaborations.fz-juelich.de/ikp/jedi/
) Collaboration aims to carry out a long term project for the measurement of the permanent electric ...dipole moments of charged particles in a storage ring. As a proof-of-concept, the COoler SYnchrotron (COSY) was equipped with a waveguide RF Wien filter designed to operate at some harmonics of the spin precession frequency ranging from 0.1 to 2 MHz. This device maintains the corresponding ratio between the RF electric and magnetic fields necessary not to induce any beam excitation and most importantly acts as a spin flipper. In the course of 2017, the waveguide RF Wien has been successfully commissioned and tested. The ability of the device to produce a Lorentz Force compensation and to rotate the particles’ polarization vector has been verified. Driven vertical spin oscillations and vertical polarization build-up has been observed. This short article briefly discusses the results of the Lorentz force measurements at 871 kHz.
The JEDI (Jülich Electric Dipole moment Investigations) collaboration performs a set of experiments at the COSY storage ring in Jülich, to search for the Electric Dipole Moments (EDMs) of charged ...particles (JEDI Collaboration
2011
). A measurement of proton and deuteron EDMs is a sensitive probe of yet unknown CP violation. The method of charged particle EDM search will exploit stored polarized beams in order to observe a miniscule rotation of the polarization axis as a function of time due to the interaction of a finite EDM with large electric fields. Key challenge is the provision of a sensitive and efficient method to determine the tiny change of the beam polarization. Elastic scattering of the beam particles on carbon nuclei will provide the polarimetry reaction. To perform these measurements, an EDM polarimeter needs to be developed. The polarimetry concept realized within the JEDI collaboration is based on a heavy crystal (LYSO) hadron calorimeter. LYSO as a fast, dense and radiation hard, novel scintillating material was chosen to fulfill these specifications. The polarimeter is designed in a compact and modular fashion consisting of modules made from LYSO crystals coupled to silicon photomultipliers (SiPM).
We developed a method to control the systematic background for Electric Dipole Moment searches in all-magnetic storage rings at the level of ≈ 10
− 20
e
⋅cm for deuterons at beam momentum 970 MeV/c. ...The method is based on a principle of spin tune modulation in a predictable way and was tested at cooler synchrotron COSY in Forschungszentrum Juelich. Two static solenoids were used as spin rotators. A special scheme of precise spin tune measurements at different spin rotation angles in solenoids allowed to determine the presence of systematic background.
Based on the notion that the local dark-matter field of axions or axionlike particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole ...moment of the latter and/or the paramagnetic axion-wind effect), we establish the feasibility of a new method to search for ALPs in storage rings. Based on previous work that allows us to maintain the in-plane polarization of a stored deuteron beam for a few hundred seconds, we perform a first proof-of-principle experiment at the Cooler Synchrotron (COSY) to scan momenta near 970 MeV/c. This entails a scan of the spin-precession frequency. At resonance between the spin-precession frequency of deuterons and the ALP-induced electric dipole moment (EDM) oscillation frequency, there is an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and, consequently, the spin-precession frequency are ramped to search for a vertical polarization change that occurs when the resonance is crossed. At COSY, four beam bunches with different polarization directions are used to make sure that no resonance is missed because of the unknown relative phase between the polarization precession and the axion or ALP field. A frequency window of 1.5 kHz width around the spin-precession frequency of 121 kHz is scanned. We describe the experimental procedure and a test of the methodology with the help of a radio-frequency Wien filter located on the COSY ring. No ALP resonance is observed. As a consequence, an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided.
Permanent Electric Dipole Moments (EDMs) of elementary particles violate two fundamental symmetries: time reversal invariance (
) and parity (
). Assuming the
theorem this implies
violation. The
...violation of the Standard Model is orders of magnitude too small to be observed experimentally in EDMs in the foreseeable future. It is also way too small to explain the asymmetry in abundance of matter and anti-matter in our universe. Hence, other mechanisms of
violation outside the realm of the Standard Model are searched for and could result in measurable EDMs. Up to now most of the EDM measurements were done with neutral particles. With new techniques it is now possible to perform dedicated EDM experiments with charged hadrons at storage rings where polarized particles are exposed to an electric field. If an EDM exists the spin vector will experience a torque resulting in change of the original spin direction which can be determined with the help of a polarimeter. Although the principle of the measurement is simple, the smallness of the expected effect makes this a challenging experiment requiring new developments in various experimental areas. Complementary efforts to measure EDMs of proton, deuteron and light nuclei are pursued at Brookhaven National Laboratory and at Forschungszentrum Jülich with an ultimate goal to reach a sensitivity of 10
− 29
e
·cm.
The history of the search for electric dipole moment (EDM)takes us back in time for more than five decades. EDMs have gained interest due to the fact that they violate the
CP
symmetry. Hence, they ...potentially provide additional sources of
CP
violation and possibly contribute to the resolution of one of the greatest puzzles of cosmology; mainly to explain the matter abundance in the universe. The JEDI collaboration is currently preparing for measuring the Deuteron EDM in the COoler SYnchrotron (COSY). One of the major challenges is the precise knowledge about the beam position along the storage ring. Transverse beam positions largely control the systematic errors. Thus the development of compact and highly sensitive Beam Position Monitors (BPMs) is particularly important for precision experiment like the EDM searches. This paper describes the development of the latest set of Rogowski coils as compact beam position monitors. It also describes some of the preliminary results towards optimizing the sensitivity of these coils by controlling the noise sources and approaching improved signal to noise ratio (SNR).
The motivation of the current R&D project is based upon the requirements of the JEDI international collaboration11http://collaborations.fz-juelich.de/ikp/jedi/. aiming to measure Electric Dipole ...Moments (EDMs) of charged particles in storage rings. One of the most important elements of such an experiment will be a specially designed polarimeter with the detection system based on a modular inorganic scintillator (LYSO crystal) calorimeter. The calorimeter modules are read out by Silicon Photo Multipliers (SiPMs). This paper describes the development of a multi-channel power supply for the polarimeter modules, providing very stable and clean bias voltages for SiPMs. In order to ensure the best possible performance of SiPMs in conjunction with the crystal-based calorimeter modules and to guarantee the required level of calorimeter stability, several quality requirements have to be met by the power supply. Additionally, it is required to provide features including remote control via the network, ramping of the output voltage, measuring and sending the information about its output voltages and currents, etc. The obtained results demonstrate that the goals for the JEDI polarimeter are met. The developed hardware will be useful in other fields of fundamental and applied research, medical diagnostic techniques and industry, where SiPMs are used.
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