Abstracts Brochure - CERN

TUPCH — Poster Session 27-Jun-06 16:00 - 18:00
Digital Techniques for BPM Measurements at the GSI Synchrotrons
In this paper we describe new approaches
for BPM measurements in hadron accelera- A.A. Galatis, A. Peters (GSI)
tors, which have strongly varying beam parameters
such as intensity, accelerating frequency and bunch length. Following signal dynamic adjustment, direct
digitalization and treatment of digitized data, we should reach a BPM resolution of 0.1mm. Interchangeability of this
method between accelerators should be provided, which results in autonomous data treatment algorithms, free of external
status and timing signalling. This should ensure the usability of the system in other bunched accelerator rings.
Different operation modes are intended for allowing online storage of beam position data over full acceleration cycles
as well as storage of beam waveforms in regions of acceleration that are of special interest e.g. transition, kicking,
bunch gymnastics. First results of realised hardware/software combinations will be introduced and discussed.
Numerical Calculations of Position Sensitivity for Linear-cut Beam Position Monitors
In this contribution the results of simulations
performed for different geometries of linear- P. Kowina, W. Kaufmann, J. Schoelles (GSI)
cut Beam Position Monitors (BPMs) are compared
for two design types: i)based on metal electrodes and ii)using a metal coated ceramics. The advantage of the
ceramic solution is a compact construction allowing easy positioning. Contrary, the construction based on the metal
electrodes benefits from its simplicity. The main goals in optimization are the sensitivity and linearity of the position
determination. High position sensitivity can be achieved by the reduction of the plate-to-plate cross talks caused by
coupling capacities. For instance, the insertion of an additional guard ring into the gap between the active plates
leads to an increase of the sensitivity by about 30%. This insertion is necessary in case of ceramic solution: The large
ceramics permeability enlarges the coupling capacity by about a factor of four. The careful geometrical arrangement
allows to avoid resonances in the interesting frequency range i.e. from 0.2 to 200MHz. The displayed simulations
are performed using CST Microwave Studio. The investigated BPMs will be used in the FAIR facility presently under
design at GSI.
Machine Protection by Active Charge-transmission Control at GSI-UNILAC
Toroidal beam current transformers (BCT)
are installed at dedicated locations along the
UNILAC accelerator. They provide an output
signal with a fixed transimpedance. Ded-
H. Reeg, J. Glatz, N. Schneider, M. Witthaus (GSI) H. Walter (New
Affiliation Request Pending)
icated signal pairs from consecutive transformers drive differential integrator stations. If preset protection levels are
exceeded due to beam charge loss during the macro-pulse, fast interlock signals are generated. The actual beam pulse
is instantaneously truncated by a fast beam chopper, avoiding any thermal damage or radio-activation of machine
components. A new BCT macro-pulse selector/display is presently under construction, which will provide
time structure observation of multiple UNILAC macro-pulses, as well as long-term data logging. The hardware is
set up with PXI components from National Instruments, running a multi-client/server controller software under
LabViewRT®. Offline-analysis of the accumulated BCT data is expected to improve the protection system’s operation
and reliability. An overview of the system layouts, technical details, and relevant operational results will be presented.
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