Automated Measurement of Beam Parameters in the COSY Injection Beam Line

The energy of the H- /D- beam injected from the cyclotron into the COSY ring is measured by means of two capacitive phase probes utilizing the time of flight method. The probes are installed in the long straight section of the injection beam line. In addition to the energy, other beam parameters such as bunch length, shape parameter and frequency can be obtained from the signals. Also the uncalibrated beam intensity can be extracted from the signals by integration. The signals from these probes are recorded and analyzed by means of an oscilloscope. The signal processing and analysis software running on the oscilloscope is written in Java. Since the software calculates the beam parameters automatically, it can be used for continuous monitoring and logging

A Permanent-Magnet Array to Maintain 3He Gas Polarization Inside a Glass Vessel for Applications in High-Energy Laser Physics

We designed and tested an array of permanent magnets (PMA) consisting of two rings with a Halbach-type magnetization pattern, which are stacked at an optimum distance such that its field homogeneity is sufficiently high to maintain the nuclear polarization of 3He gas for future laser experiments. The design included the magnetic layout, the selection of appropriate magnets, and the calculation of the expected relaxation time for the polarized gas. After assembly, we measured the magnetic field in the center region of the PMA. We transferred polarized gas samples from the magnetized transport box into the PMA and determined the relaxation time with four magnetic field sensors in a gradiometric arrangement, detecting the decay of the stray field of the polarized gas on the order of 100 nT in a background field of 1.3 mT. The extracted polarization lifetime of about 21 h is sufficient for the planned experiments at high-power laser facilities

A polarized 3He Target for the Exploration of Spin Effects in Laser-induced Plasmas

In order to investigate the polarization degree of laser-accelerated 3He ions from a polarized 3He gas-jet target, several challenges have to be overcome. One of these is the development of an appropriate polarized 3He gas-jet target. Since our experiments are carried out at the PHELIX Petawatt Laser Facility, GSI Darmstadt, the layout of the set-up has to cope with the available space within the PHELIX target chamber. The essential components of such a layout are a magnetic holding field for storing polarized 3He gas inside the vacuum chamber for many hours, the gas-jet source for providing the desired laser target, and finally, a polarimeter for measuring the spin-polarization degree of laser-accelerated 3He2+ ions