| Paper | Title | Other Keywords | Page | ||
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| PS10 | Control and Data Analysis for Emittance Measuring Devices | instrumentation, diagnostics, GSI, emittance | 126 | ||
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Due to the wide range of heavy ion beam intensities and energies in the
GSI linac and the associated transfer channel to the synchrotron, several
different types of emittance measurement systems have been established.
Many common devices such as slit/grid or dipole-sweep systems are
integrated into the GSI control system. Other systems like the single
shot pepper pot method using CCD-cameras or stand-alone slit/grid set-ups
are connected to personal computers. An overview is given about the
various systems and their software integration. Main interest is directed
on the software development for emittance front-end control and data
analysis such as evaluation algorithms or graphical presentation of the
results. In addition, special features for improved usability of the
software such as data export, project databases and automatic report
generation will be presented. An outlook on a unified evaluation
procedure for all different types of emittance measurement is given.
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| PS15 | A New Wirescanner Control Unit | instrumentation, diagnostics, DESY, emittance | 139 | ||
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Wires scanners are standard instruments for beam size measurements in
storage rings: A wire is crossing the beam at a given speed and the
secondary emission current of the wire and/or the photomultiplier signals
produced from Bremsstrahlung or particles scattered at the wire are
recorded together with the wire positions. The control unit described
here is based on a previous CERN design. It now has additional features:
Triggered fast scans (1m/s) with a trigger uncertainty below ±30μs
(mechanics + electronics) used at the TTF Linac and at the proton
synchrotron DESY III, Slow scans (e.g. 50μm/s) for the TTF Linac,
Positioning of the wire within ±3μm for tail scans at the storage
rings PETRA and HERA, A 10.5MHz data acquisition rate for bunch-by-bunch
acquisitions in the accelerators at DESY. Another important design goal
was the compatibility with CERN scanners; it is foreseen to operate them
at LHC with the new control unit. First measurements with the new control
unit at TTF and HERA will be presented.
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| PS19 | Status of the Delta Synchrotron Light-Monitoring-System | instrumentation, diagnostics, DELTA, synchrotron-radiation | 148 | ||
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Synchrotron radiation sources like DELTA need an optical monitoring
system to measure the beam size at different points of the ring with high
resolution and accuracy. An investigation of the emittance of the storage
ring can also be done by these measurements.
Scope of this paper is the investigation of the resolution limit of the
different types of optical synchrotron light monitors at DELTA, a third
generation synchrotron radiation source. At first the normal synchrotron
light monitor is analysed. The minimum measurable electron beamsize at
DELTA is about 80μm. Emphasis is then put on a special synchrotron
light interferometer, developed for DELTA, which has been built up and
tested. This interferometer uses the same beamline and can measure
beamsizes down to about 8μm. So its resolution is about ten times
better and sufficient for the expected small vertical beamsizes at DELTA.
Measurements of the electron beamsize and emittance were done with both
(synchrotron light monitor and interferometer) at different energies.
The image processing system based on a PC Framegrabber generates a
gaussian fit to the images from different synchrotron light-monitors and
calculates the beamsizes and positions.
An investigation of possible reasons of beam movements will be appended,
because the theoretical values of the present optics are smaller than the
measured emittance.
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| PM02 | Signal Processor for Spring8 Linac BPM | instrumentation, diagnostics, linac, pick-up, SPring-8 | 162 | ||
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A signal processor of the single shot BPM system consists of a
narrow-band BPF unit, a detector unit, a P/H circuit, an S/H IC and a
16-bit ADC. The BPF unit extracts a pure 2856MHz RF signal component from
a BPM and makes the pulse width longer than 100ns. The detector unit that
includes a demodulating logarithmic amplifier is used to detect an S-band
RF amplitude. A wide dynamic range of beam current has been achieved;
0.01 ~ 3.5nC for below 100ns input pulse width, or 0.06 ~ 20mA for above
100ns input pulse width. The maximum acquisition rate with a VME system
has been achieved up to 1kHz.
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| PM07 | Orbit Control at the Advanced Photon Source
Work supported by the US Department of Energy |
instrumentation, diagnostics, closed-orbit, APS, pick-up | 177 | ||
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The Advanced Photon Source (APS) began operation in 1995 with the
objective of providing ultra-stable high-brightness hard x-rays to its
user community. This paper will be a review of the instrumentation and
software presently in use for orbit stabilization. Broad-band and
narrow-band rf beam position monitors as well as x-ray beam position
monitors supporting bending magnet and insertion device source points are
used in an integrated system. Status and upgrade plans for the system
will be discussed.
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| PM08 | Advanced Photon Source RF Beam Position Monitor System Upgrade Design and Commissioning | instrumentation, diagnostics, closed-orbit, APS, pick-up | 180 | ||
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This paper describes the Advanced Photon Source (APS) storage ring
mono-pulse rf beam position monitor (BPM) system upgrade. The present rf
BPM system requires a large dead time of 400 ns between the measured
bunch and upstream bunch. The bunch pattern is also constrained by the
required target cluster of six bunches of 7 mA minimum necessary to
operate the receiver near the top end of the dynamic range. The upgrade
design objectives involve resolving bunches spaced as closely as 100 ns.
These design objectives require us to reduce receiver front-end losses
and reflections. An improved trigger scheme that minimizes systematic
errors is also required. The upgrade is in the final phases of
installation and commissioning at this time. The latest experimental and
commissioning data and results will be presented.
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| PM10 | A Logarithmic Processor for Beam Position Measurements Applied to a Transfer Line at CERN | instrumentation, diagnostics, pick-up, closed-orbit, beam-transport | 186 | ||
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The transfer line from the CERN proton synchrotron
(PS) to the super proton synchrotron (SPS) requires a new
beam position measurement system in view of the LHC.
In this line, the single passage of various beam types
(up to 7), induces signals with a global signal dynamics of
more than 100 dB and with a wide frequency spectral
distribution.
Logarithmic amplifiers, have been chosen as technical
solution for the challenges described above.
The paper describes the details of the adopted solutions
to make beam position measurements, with a resolution
down to few 10-4 of the full pickup aperture over more
than 50 dB of the total signal dynamics.
The reported performances has been measured on the
series production cards, already installed into the machine
and on one pickup in the transfer line.
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| PM12 | The SPS Individual Bunch Measurement System | instrumentation, diagnostics, pick-up, CERN-SPS | 192 | ||
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The Individual Bunch Measurement System (IBMS)
allows the intensity of each bunch in an LHC batch to be
the measured both in the PS to SPS transfer lines and in
the SPS ring itself. The method is based on measuring the
peak and valley of the analogue signal supplied by a Fast
Beam Current Transformer at a frequency of 40MHz. A
12 bit acquisition system is required to obtain a 1 %
resolution for the intensity range of 5×109 to 1.7×1011
protons per bunch, corresponding to the pilot and ultimate
LHC bunch intensities. The acquisition selection and
external trigger adjustment system is driven by the
200MHz RF, which is distributed using a single-mode
fibre-optic link. A local oscilloscope, controlled via a
GPIB interface, allows the remote adjustment of the
timing signals. The low-level software consists of a realtime
task and a communication server run on a VME
Power PC, which is accessed using a graphical user
interface. This paper describes the system as a whole and
presents some recent uses and results from the SPS run in
2000.
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| PM13 | Control Modules for Scintillation Counters in the SPS Experimental Areas | instrumentation, diagnostics, beam-transport, CERN-SPS | 195 | ||
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The hardware used in the SPS Experimental Areas to control the beam
instrumentation electronics and mechanics of the particle detectors is
based on CAMAC and NIM modules. The maintenance of this hardware now
presents very serious problems. The modules used to operate the
Experimental Areas are numerous and older than 20 years so many of them
cannot be repaired any more and CAMAC is no longer well supported by
industry. The fast evolution of technology and a better understanding of
the detectors allow a new equipment-oriented approach, which is more
favourable for maintenance purposes and presents fewer data handling
problems. VME and IP Modules were selected as standard components to
implement the new electronics to control and read out the particle
detectors. The first application implemented in this way concerns the
instrumentation for the Scintillation Counters (formerly referred to as
triggers). The fundamental options and the design features will be
presented.
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| PM17 | First Beam Tests for the Prototype LHC Orbit and Trajectory System in the CERN-SPS | instrumentation, diagnostics, pick-up, closed-orbit, LHC, collider | 207 | ||
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The first beam tests for the prototype LHC orbit and
trajectory system were performed during the year 2000 in
the CERN-SPS. The system is composed of a wide-band
time normaliser, which converts the analogue pick-up
signals into a 10 bit position at 40MHz, and a digital
acquisition board, which is used to process and store the
relevant data. This paper describes the hardware involved
and presents the results of the first tests with beam.
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| PM19 | The Dynamic Tracking Acquisition System for DAΦNE e+/e--Collider | instrumentation, diagnostics, pick-up, closed-orbit, collider, DAPHNE | 213 | ||
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The goal of this paper is to describe the dynamic tracking acquisition
system implemented for the DAΦNE e+/e--collider at LNF/INFN. We have
been using the system since last year and it has been possible to collect
useful information to tune-up the machine.
A four-button BPM is used to obtain the sum and difference signals in
both the transverse planes. The signals are acquired and recorded by a
LeCroy LC574A oscilloscope with the capability to sample the input
waveforms using a beam synchronous external clock generated by the DaFne
Timing System. The start of acquisition is synchronised to a horizontal
kick given by an injection kicker. After capturing up to 5000 consecutive
turns, data are sent through a GPIB interface to a PC, for processing,
presentation and storage. A calibration routine permits to convert
voltage data to millimeters values. The acquisition and control program
first shows the decay time in number of turns. Then it draws a trajectory
in the phase space (position and speed) in both the transverse planes. To
do this the software builds a data vector relative to a second "virtual"
monitor advanced by 90 degrees. This is done by two alternative ways:
applying the Hilbert transform or using the transport matrix method.
Examples of data acquired during the collider tune-up are shown.
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| PM21 | DSP and FPGA Based Bunch Current Signal Processing | instrumentation, diagnostics, ESRF, closed-orbit, simulation | 219 | ||
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The current in electron storage rings used as synchrotron light sources
must be measured to a very high precision in order to determine the
stored beam lifetime. This is especially so in high-energy machines in
which the lifetime may be very high. Parametric current transformers
(PCT) have traditionally been used to measure the DC or average current
in the machine, which offer a very high resolution. Unfortunately these
do not allow the different components of a complex filling pattern to be
measured separately. A hybrid filling mode delivered at the ESRF consists
of one third of the ring filled with bunches with a single highly
populated bunch in the middle of the two-thirds gap. The lifetime of
these two components may be very different. Similarly the two components
are injected separately and can be monitored separately using a fast
current transformer (FCT) or an integrating current transformer (ICT).
The signals from these devices can be analysed using high speed analogue
to digital converters operating at up to 100MHz and digital signal
processing (DSP) techniques involving the use of field programmable gate
arrays (FPGAs) in order to process the continuous data stream from the
converters.
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