The proposed method exploits charged particles confined as a storage ring beam (proton, deuteron, possibly \(^3\)He) to search for an intrinsic electric dipole moment (EDM) aligned along the particle ...spin axis. Statistical sensitivities could approach 10\(^{-29}\) e\(\cdot\)cm. The challenge will be to reduce systematic errors to similar levels. The ring will be adjusted to preserve the spin polarisation, initially parallel to the particle velocity, for times in excess of 15 minutes. Large radial electric fields, acting through the EDM, will rotate the polarisation from the longitudinal to the vertical direction. The slow rise in the vertical polarisation component, detected through scattering from a target, signals the EDM. The project strategy is outlined. A stepwise plan is foreseen, starting with ongoing COSY activities that demonstrate technical feasibility. Achievements to date include reduced polarization measurement errors, long horizontal plane polarization lifetimes, and control of the polarization direction through feedback from scattering measurements. The project continues with a proof-of-capability measurement (precursor experiment; first direct deuteron EDM measurement), an intermediate prototype ring (proof-of-principle; demonstrator for key technologies), and finally a high-precision electric-field storage ring.
A calorimetric polarimeter based on inorganic LYSO scintillators is described. It has been designed for use in a storage ring to search for electric dipole moments (EDM) of charged particles such as ...the proton and deuteron. Its development and first use was on the Cooler Synchrotron (COSY) at the Forschungszentrum J\"ulich with 0.97 GeV/c polarized deuterons, a particle and energy suitable for an EDM search. The search requires a polarimeter with high efficiency, large analyzing power, and stable operating characteristics. With typical beam momenta of about 1 GeV/c, the scattering of protons or deuterons from a carbon target into forward angles becomes a nearly optimal choice of an analyzing reaction. The polarimeter described here consists of 52 LYSO detector modules, arranged in 4 symmetric blocks (up, down, left, right) for energy determination behind plastic scintillators for particle identification via energy loss. The commissioning results of the current setup demonstrate that the polarimeter is ready to be employed in a first direct search for an EDM on the deuteron, which is planned at COSY in the next two years.
The high-energy storage ring (HESR) of the international facility for antiproton and ion research (FAIR) at GSI in Darmstadt is dedicated to strong interaction studies with antiprotons in the ...momentum range from 1.5 to 15 GeV/c. Powerful phase-space cooling is needed to reach demanding experimental requirements in terms of luminosity and beam quality. Status and details of technical planning including cryogenic concept will be presented.
This project exploits charged particles confined as a storage ring beam (proton, deuteron, possibly \(^3\)He) to search for an intrinsic electric dipole moment (EDM, \(\vec d\)) aligned along the ...particle spin axis. Statistical sensitivities can approach \(10^{-29}\)~e\(\cdot\)cm. The challenge will be to reduce systematic errors to similar levels. The ring will be adjusted to preserve the spin polarization, initially parallel to the particle velocity, for times in excess of 15 minutes. Large radial electric fields, acting through the EDM, will rotate the polarization (\(\vec d \times\vec E\)). The slow rise in the vertical polarization component, detected through scattering from a target, signals the EDM. The project strategy is outlined. It foresees a step-wise plan, starting with ongoing COSY activities that demonstrate technical feasibility. Achievements to date include reduced polarization measurement errors, long horizontal-plane polarization lifetimes, and control of the polarization direction through feedback from the scattering measurements. The project continues with a proof-of-capability measurement (precursor experiment; first direct deuteron EDM measurement), an intermediate prototype ring (proof-of-principle; demonstrator for key technologies), and finally the high precision electric-field storage ring.
The superconducting injector linac COSY-SCL is being designed and constructed at the Forschungszentrum Juelich. The train goal of the new injector is to fill the cooler synchrotron COSY with ...polarized protons as well as with polarized deuterons up to the space-charge limit at injection energy. COSY-SCL is characterized by a base frequency of 160 MHz, 25 kV ion-source extraction voltage, a pulse length of up to 500 /spl mu/s, a maximum repetition rate of 2 Hz, injection into the linac at /spl beta/=0.073 and injection into COSY at kinetic energies of 52 MeV for protons and 56 MeV for deuterons, respectively. The injector configuration is presented, and its main subsystems-ion source (CIPIOS from IUCF for polarized H/sup -/ and D/sup -/), RFQ (built in co-operation with the University of Frankfurt), linac (based on half-wave resonators operating at 160 and 320 MHz)- are described and discussed. The present status of the project is reported.
An atomic-beam target (ABT) for the EDDA experiment has been built in Bonn and was tested for the very first time at the cooler synchrotron COSY. The ABT differs from the polarized colliding-beams ...ion source for COSY in the DC-operation of the dissociator and the use of permanent 6-pole magnets. At present the beam optics of the ABT is set-up for maximum density in the interaction zone, but for target-cell operation it can be modified to give maximum intensity. The modular concept of this atomic ground-state target allows to provide all vector- (and tensor) polarizations for protons and deuterons, respectively. Up to now the polarization of the atomic-beam could be verified by the EDDA experiment to be > or approx. 80% with a density in the interaction zone of > or approx. 10{sup 11} atoms/cm{sup 2}.
The polarized ion source at the cooler synchrotron COSY in Juelich has been designed for the cooler synchrotron COSY and the injector cyclotron JULIC. The source is based on the colliding beams ...concept and delivers an pulsed H{sup -} current of over 20 {mu}A within an emittance {epsilon} of less than 0.5 {pi} mm mrad ({beta}{gamma} normalized). The polarization P is in excess of 85%. A substantial enhancement of the H{sup -} current results from the pulsing of the atomic beam part and the improvement of the neutral cesium intensity.
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 \(\nu_s = \gamma ...G\) (gamma is the Lorentz factor, \(G\) the magnetic anomaly). For 970 MeV/c deuterons coherently precessing with 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 \(1 \cdot 10^{-10}\) 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.
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