Session 8: Low and Intermediate Energy Accelerators and ... - CERN

measurement system for the cyclotron magnet is
described, and measurement results are presented.
Type of presentation requested: Poster
Classification: [A04] Low- and Intermediate-Energy
Circular Accelerators
21-1130 - The Bunch Compressor System for SIS18
at GSI
Peter Hülsmann, Martin Emmerling, Werner
Gutowski, Gerald Hutter, Wolfgang Vinzenz (GSI,
Darmstadt)
For bunch compression down to pulse durations of 50
ns, a dedicated rf system is under development for the
SIS12/18 heavy ion synchrotron upgrade and will be
described in this paper. Due to space restrictions in
SIS12/18 the rf system consists of very short cavities
which provide a very large voltage gradient (50 kV/m)
at a very low frequency of approximately 800 kHz and
rf final stages which provide a short rise time. The only
possibilty to meet the requirements is the application of
a cavity heavily inductively loaded by metallic alloy
(MA) ring cores. This new rf system will be a
prototype for the advanced acceleration and
compression system needed in SIS100, which is the
most important part for the proposed International
Acceleration Facility at GSI. In order to gain
experience with different MA ring core materials two
of the four compressor cavities are loaded differently,
which gives us an opportunity to learn the operational
advantages of both materials. It is expected that the
experimental results will support the final judgement
for the future rf system in SIS100.
Type of presentation requested: Poster
Classification: [A04] Low- and Intermediate-Energy
Circular Accelerators
22-1131 - Upgrading the AC Power Supply to the
ISIS Main Magnet Circuit
Steve West, James Gray, Adrian Morris
(CCLRC/RAL/ISIS, Chilton, Didcot, Oxon)
ISIS, situated at the Rutherford Appleton Laboratory
(RAL) is the world?s most powerful pulsed neutron
source. At the heart of the ISIS accelerator is a proton
synchrotron which uses a ring of magnets connected in
series and configured as a ?White Circuit?. The
magnets are connected in series with capacitor banks
so that they form a resonant circuit with a fundamental
frequency of 50 Hz. The circuit allows the magnets to
be fed with an AC current superimposed on a DC
current. The AC is currently provided by a 1MVA
Motor-Alternator set and it is now proposed to replace
this by a solid state UPS (Uninterruptible Power
Supply) system. Tests on a smaller 80kVA unit have
shown that it is possible to control the magnet current
with a modified UPS system in such a way that both
the frequency, phase and output voltage are under the
direct influence of the control system. This paper
discusses the issues surrounding the upgrading of AC
supply to the main magnets with a view to improving
the system reliability, improving magnet current stability
and reducing the risk of mains failure.
Type of presentation requested: Poster
Classification: [A04] Low- and Intermediate-Energy
Circular Accelerators
23-1164 - Status of the Cooler Synchrotron Cosy-juelich
Bernd Lorentz (FZJ/COSY, Jülich), Ralf Eichhorn, Ralf
Gebel, Herbert Schneider (FZJ, Julich), Ulf Bechstedt,
Jürgen Dietrich, Andreas Lehrach, Rudolf Maier,
Dieter Prasuhn, Alexander Schnase, Rolf Stassen, Hans
Stockhorst, Raimund Tölle (FZJ/IKP, Jülich)
The cooler synchrotron COSY accelerates and stores
unpolarized and polarized protons and deuterons in the
momentum range between 300 MeV/c to 3.65 GeV/c. To
provide high quality beams, an Electron Cooler at injection
and a Stochastic Cooling System from 1.5 GeV/c up to
maximum momentum are available. Vertically polarized
proton beams with a polarization of more than 0.80 are
delivered to internal and external experimental areas at
different momenta. Externally, the maximum momentum is
up to date restricted to approximately 3.4 GeV/c by the
extraction elements installed in COSY. In 2003 deuteron
beams with different combinations of vector and tensor
polarization were made available for internal and external
experiments. An rf dipole was installed, which is used to
induce artificial depolarizing resonances. It can be used for
an accurate determination of the momentum of the stored
beams. The status of the cooler synchrotron COSY is
presented and future plans are discussed.
Type of presentation requested: Poster
Classification: [A04] Low- and Intermediate-Energy
Circular Accelerators
24-1197 - A Double Electrostatic Storage Ring,
DESIREE
Karl-Gunnar Rensfelt, Lars Bagge, Mikael Blom,
Håkan Danared, Leif Liljeby, Andras Paal, Ansgar
Simonsson, Örjan Skeppstedt (MSL, Stockholm),
Henrik Cederquist, Jens-Peter Jensen, Mats Larsson, Sven
Mannervik, Henning Schmidt, Kjell Schmidt (Stockholm
University, Stockholm)
The advantages of storage rings with only electrostatic
elements were first demonstrated by ELISA in Aarhus and
later in other places. At MSL and Fysikum at Stockholm
University the ideas have been developed further in the
Double Electrostatic Storage Ion Ring ExpEriment,
DESIREE. Beams of negative and positive ions will be
merged in a common straight section of the rings so that low
energy collisions can be studied. Furthermore the rings will
be cooled to 10 - 20 K in order to relax internal excitations
in circulating molecules. A design report can be found at
www.msl.se. The project is now (January 2004) almost fully
financed and the final design work has recently been started.
The paper will shortly review the physics programme and
describe the status of the design work.