Rene Geithner

Application of LTS-SQUIDs in Nuclear Measurement Techniques

Low temperature superconducting quantum interference devices (LTS SQUIDs) are used to make precision measurements of electromagnetic fields in applications ranging from biomedicine to high energy physics. We have previously described an LTS SQUID-based device for nuclear physics which employs the Cryogenic Current Comparator principle (CCC). The CCC consists of a high-performance LTS DC SQUID system, a toroidal pick-up coil, and a meander-shaped superconducting niobium shield. Theoretical investigations show that as external noise decreases, improvements in performance depend on the properties of the ferromagnetic core material embedded in the pick-up coil. Here we present the temperature- and frequency-dependence of several candidate ferromagnetic and nanocrystalline materials. We discuss these results in light of the optimization of the CCC sensor performance.

Non-perturbative measurement of low-intensity charged particle beams

Non-perturbative measurements of low-intensity charged particle beams are particularly challenging to beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy antiproton decelerator (AD) and the future extra low energy antiproton rings at CERN, an absolute measurement of the beam intensity is essential to monitor the operation efficiency. Superconducting quantum interference device (SQUID) based cryogenic current comparators (CCC) have been used for measuring slow charged beams in the nA range, showing a very good current resolution. But these were unable to measure fast bunched beams, due to the slew-rate limitation of SQUID devices and presented a strong susceptibility to external perturbations. Here, we present a CCC system developed for the AD machine, which was optimised in terms of its current resolution, system stability, ability to cope with short bunched beams, and immunity to mechanical vibrations. This paper presents the monitor design and the first results from measurements with a low energy antiproton beam obtained in the AD in 2015. These are the first CCC beam current measurements ever performed in a synchrotron machine with both coasting and short bunched beams. It is shown that the system is able to stably measure the AD beam throughout the entire cycle, with a current resolution of .

A squid-based beam current monitor for FAIR/CRYRING

A SQUID-based beam current monitor was developed for the upcoming FAIR-Project, providing a non-destructive online monitoring of the beam currents in the nA-range. The cryogenic current comparator (CCC) was optimized for lowest possible noise-limited current resolution together with a high system bandwidth. This CCC is foreseen to be installed in the CRYRING facility (CRYRING@ESR: A study group report www.gsi.de/fileadmin/SPARC/documents/Cryring/ReportCryring_40ESR.PDF), working as a test bench for FAIR. In this contribution we present results of the completed CCC for FAIR/CRYRING and also arrangements that have been done for the installation of the CCC at CRYRING, regarding the cryostat design.

A Non-Destructive Beam Monitoring System Based on an LTS-SQUID

Monitoring of beam currents in particle accelerators without affecting the beam guiding elements, interrupting the beam or influencing its profile is a major challenge in accelerator technology. A solution to this problem is the detection of the magnetic field generated by the moving charged particles. We present a non-destructive beam monitoring system for particle beams in accelerators based on the Cryogenic Current Comparator (CCC) principle. The CCC consists of a high-performance low-temperature DC superconducting quantum interference device (LTS DC-SQUID) system, a toroidal pick-up coil, and a meander-shaped superconducting niobium shield. This device allows the measurement of continuous as well as pulsed beam currents in the nA-range. The resolution and the frequency response of the detector strongly depend on the toroidal pick-up coil and its embedded ferromagnetic core. Investigations of both the temperature and frequency dependence of the relative permeability and the noise contribution of several nanocrystalline ferromagnetic core materials are crucial to optimize the CCC with respect to an improved signal-to-noise ratio and extended transfer bandwidth.

Physical Society of Japan : Superconducting beam charge monitors for antiproton storage rings

Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 1 Institute for Solid State Physics, Friedrich Schiller University, D-07743 Jena, Germany 2 Institute for Optics and Quantum Electronics, Friedrich Schiller University, D-07743 Jena, Germany 3 Helmholtz Institute Jena, D-07743 Jena, Germany 4 GSI Helmholtz Center for Heavy Ion Research, D-64291 Darmstadt, Germany 5 The Cockcroft Institute, University of Liverpool, Daresbury, Cheshire WA4 4AD, U.K 6 CERN European Organization for Nuclear Research, CH-1211 Geneva, Switzerland

Beam Current Monitors for FAIR

The FAIR (Facility for Antiproton and Ion Research) accelerator facility presently under construction at GSI will supply a wide range of beam intensities for physics experiments. Design beam intensities range from 2.5×10 13 protons/cycle to be delivered to the pBar-target and separator for production of antiprotons, to beams of e.g. 10 9 ions/s in the case of slowly extracted beams. The large intensity range demands for dedicated beam current monitors for precise, non-destructive beam intensity measurements in the synchrotrons, transport lines and storage rings of the FAIR facility. This report describes GSI developments of purpose-built beam current monitors for the SIS100 synchrotron and high-energy beam transport lines (HEBT) of FAIR. Prototype measurements with a SQUID-based Cryogenic Current Comparator and a resonant beam charge transformer are presented, and possibilities for further upgrades are discussed.