L. Barion

Spin tune mapping as a novel tool to probe the spin dynamics in storage rings

Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ult ...

Test of the CLAS12 RICH large scale prototype in the direct proximity focusing configuration

Abstract.A large-area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3GeV/c up to 8GeV/c for the CLAS12 experiment at the upgraded 12GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and highly packed and highly segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large-angle tracks). We report here the results of the tests of a large-scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1 : 500 in the whole momentum range.

Magnetic System for the CLAS12 Proposal

The conceptual design of a magnetic system for an experiment to measure the transverse spin effects in semi-inclusive Deep Inelastic Scattering (SIDIS) at 11 GeV with a transversely polarized target using the CLAS12 detector at Jefferson Lab is presented. A proposal has been submitted to study spin azimuthal asymmetries in SIDIS using an 11-GeV polarized electron beam from the upgraded CEBAF facility and the CLAS12 detector equipped with a transversely polarized target. The main focus of the experiment will be the measurement of transverse target single and double spin asymmetries in the reaction ep↑ → ehX, where e is an electron, p↑ is transversely polarized proton, h is a meson (e.g., a pion or a kaon) and X is the undetected final state. The details of the conceptual design of the shielding magnetic system and transverse dipole are reported.

Phase measurement for driven spin oscillations in a storage ring

This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. ...

Upgrade of the PAX H and D polarized internal target for precision measurements at COSY

In order to accomplish to the needing of future experiments, the PAX collaboration 1 is performing an upgrade of the polarized internal target presently installed at the COSY ring in Jülich (Germany). The implementation of a new dual cavity will allow to switch from H to D and to measure the gas polarization without hardware change in a daily time. The introduction of an openable storage cell will increase the ring acceptance at injection and the intensity of the stored beam. The new setup will be adopted in spin-filtering 2 measurements as a mechanism to produce polarized antiprotons and in a recently proposed test of Time Reversal Invariance foreseen at the COSY ring. In the report, the status of the development of the apparatus and the plans of the Collaboration will be illustrated.

Design of a Test Bench for

An innovative test bench for high-temperature superconducting (HTS) cables has been designed and is presently under construction at the Cryogenic Laboratory of the University of Ferrara and INFN-Ferrara, Italy. The aim of the test bench is to measure the critical current as a function of tension or compression of a straight MgB2 and HTS wire at their working temperature. Currents up to 600 A will be supplied to a 120-mm-long wire, which can be cooled down to 20 K by cold-heads in vacuum. A piece of information from the traction bench will be synchronized with the power supply and quench protection system. Because the stress is constant on the wire cross-section, the measurement of the properties of a straight-wire represents a direct measurement of the strain behavior of the HTS wire. The full mechanical design will be illustrated together with the complete data acquisition system.