CERN, Geneva
Fermilab, Batavia
Prior to the re-start of the Large Hadron Collider LHC in 2009 the protection system for superconducting magnets and bus bars QPS will be submitted to a substantial upgrade. The foreseen modifications will enhance the capability of the system in detecting problems related to the electrical interconnections between superconducting magnets as well as the detection of so-called symmetric quenches in the LHC main magnets. The paper will describe the design and implementation of the new protection layers and report as well on the commissioning of the system and first operational results.
CERN, Geneva
CIRTEM, Labege CEDEX
The search for higher magnetic fields in particle accelerators increasingly demands the use of superconducting magnets. This magnet technology has a large amount of magnetic energy storage during operation at relatively high currents. As such, many monitoring and protection systems are required to safely operate the magnet, including the monitoring of any leakage of current to earth in the superconducting magnet that indicates a failure of the insulation to earth. At low amplitude, the earth leakage current affects the magnetic field precision. At a higher level, the earth leakage current can additionally generate local losses which may definitively damage the magnet or its instrumentation. This paper presents an active earth fault current monitoring circuit, widely deployed in the CERN-LHC converters for the superconducting magnets. The circuit allows the detection of earth faults before energising the circuit as well as limiting any eventual earth fault current. The electrical stress on each circuit component is analyzed and advice is given for a totally safe component selection in relation to a given load.
LBNL, Berkeley, California
Fermilab, Batavia
BNL, Upton, Long Island, New York
Funding: This work was supported in part by the Director, Office of Science, High Energy Physics, U.S. Department of Energy under contract No. DE-AC02-05CH11231
Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Large Hadron Collider (LHC) at CERN. Nb3Sn conductor is at the present time the only practical superconductor capable of generating fields beyond 10 T. In support of the LHC Phase-II upgrade, the US LHC Accelerator Research Program (LARP) is developing a large bore (120mm) IR quadrupole (HQ) capable of reaching 15 T at its conductor peak field. The 1 m long two-layer coil, based on the design of the LARP TQ quadrupole series that achieved 230 T/m in a 90 mm bore, will demonstrate additional features such as alignment and accelerator field quality while exploring the magnet performance limits in terms of gradient, forces and stresses. In this paper we summarize the design and report on the magnet construction progress.
CERN, Geneva
Following a series of injection tests, the first attempts to pass beam around both directions of the LHC were successful and led rapidly to circulating beam in the counter clockwise direction (beam 2) and many turns of beam 1. Unfortunately the beam commissioning was curtailed by the incident in sector 34. However, measurements performed during this first commissioning period should that the magnet model of the machine had delivered optics close to nominal, and also very good performance of beam instrumentation and supporting software. Details of the machine set-up and the commissioning procedures are detailed. The measurements performed and the key results from this period are described.
CERN, Geneva
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
ORNL, Oak Ridge, Tennessee
BNL, Upton, Long Island, New York
PU, Princeton, New Jersey
Fermilab, Batavia
The MERIT experiment is a proof-of-principle test of a target system for high power proton beam to be used as front-end for a neutrino factory complex or a muon collider. The experiment took data in autumn 2007 with the fast extracted beam from the CERN Proton Synchrotron (PS) to a maximum intensity of about 30·1012 protons per pulse. We report results from the portion of the MERIT experiment in which separated beam pulses were delivered to a free mercury jet target with time intervals between pulses varying from 2 to 700 microseconds. The analysis is based on the responses of particle detectors placed along side and downstream of the target.
CERN, Geneva
Initial commissioning of the LHC beam dump system with beam took place in August and September 2008. The preparation, setting-up and the tests performed are described together with results of the extractions of beam into the dump lines. Analysis of the first detailed aperture measurements of extraction channels and kicker performance derived from dilution sweep shapes are presented. The performance of the other equipment subsystems is summarised, in particular that of the dedicated dump system beam instrumentation.
CERN, Geneva
After each beam dump in the LHC automatic post-operational checks are made to guarantee that the last beam dump has been executed correctly and that the system can be declared to be 'as good as new' before the next injection is allowed. The analysis scope comprises the kicker waveforms, redundancy in kicker generator signal paths and different beam instrumentation measurements. This paper describes the implementation and the operational experience of the internal and external post-operational checks of the LHC beam dumping system during the commissioning of the LHC without beam and during the first days of beam operation.
Fermilab, Batavia
DESY, Hamburg
INFN/LASA, Segrate (MI)
CEA, Gif-sur-Yvette
Albert Einstein, Leibniz Universität, Hannover
With a view to the series production of one hundred, 12 m long XFEL 1.3 GHz cryomodules and their transportation from the assembly site at CEA Saclay (F) to the installation site at DESY Hamburg (D) a test transportation of a FLASH cryomodule has been performed, in the condition foreseen for the mass transportation. The present study examines the stresses induced on the module and verify the damping capabilities of the transport frame in order to minimize risk of damage to the most critical components. During the transportation, acceleration and vibration have been monitored as well as coupler antenna contacts and vacuum performances. This paper describes the analysis performed and compares those results to the data of a similar transportation study at Fermilab for the CM1 cryomodule.
CERN, Geneva
Virtually all modern accelerator control systems are nowadays based on commercial-off-the-shelf products (VME crates, PLCs, SCADA systems, etc.), on Windows or Linux PCs, and on communication infrastructures using Ethernet and TCP/IP. Despite the benefits coming with this (r)evolution, these "modern" control systems and infrastructures usually completely lack adequate levels of robustness, resilience and security. Even worse, new threats are inherited, too: Worms and viruses spread within seconds via the Ethernet cable, and attackers are becoming interested in breaking into control systems. This talk will discuss the initial security risks, what precautions are needed to protect control systems against cyber threats and how to provide a secure environment without sacrificing operability.
CERN, Geneva
During the 2008 LHC injection synchronisation tests and the subsequent days with circualting beam, the majority of the LHC beam instrumentation systems were capable of measuring their first beam parameters. This includes the two large, distributed, beam position and beam loss systems, as well as the scitillating and OTR screen systems, the fast and DC beam current transformer systems, the tune measurement system and the wire scanner system. The fast timing system was also extensively used to synchronise most of this instrumentation. This paper will comment on the results to date, some of the problems observed and improvements to be implemented before the next LHC run.
DESY, Hamburg
Warsaw University of Technology, Institute of Electronic Systems, Warsaw
TUL-DMCS, Łódź
Future RF Control systems will require simultaneuous data acquisition of up to 100 fast ADC channels at sampling rates of around 100 MHz and real time signal processing within a few hundred nanoseconds. At the same time the standardization of low-level systems are common objectives for all laboratories for cost reduction, performance optimization and machine reliability. Also desirable are modularity and scalability of the design as well as compatibility with accelerator instrumentation needs including the control system. All these requirements can be fulfilled with the new telecommunication standard ATCA when adopted to the domain of instrumentation. We describe the architecture and design of an ATCA based LLRF system for the European XFEL. Initial results of the demonstration of such a system at the FLASH user facility will be presented.
BNL, Upton, Long Island, New York
The outer circumference of a BPM button and the inner circumference of the button housing comprise a transmission line. This transmission line typically presents an impedance of a few tens of ohms to the beam, and couples very weakly to the 50 Ω coaxial transmission line that comprises the signal path out of the button. The modes which are consequently excited and trapped often have quality factors of several hundred, permitting resonant excitation by the beam. The combination of short bunches and high currents found in modern light sources and colliders can result in the deposition of tens of watts of power in the buttons. The resulting thermal distortion is potentially problematic for maintaining high precision beam position stability, and in the extreme case can result in mechanical damage. We present here a simple algorithm that uses the input parameters of beam current, bunch length, button diameter, beampipe aperture, and fill pattern to calculate a figure-of-merit for button heating. Data for many of the world’s light sources and colliders is compiled in a table.
I-Tech, Solkan
ELETTRA, Basovizza
Libera Brilliance is a standard device for beam position monitoring on circular synchrotron light sources. Initially, the idea of optimizing its signal processing for the single bunch measurement came from the users community. This was afterwards followed by the idea of using it on transfer lines on the same 3rd generation light sources as well as on injector system for the FELs. The device can be used on pickup buttons and on striplines. The single pass functionality is contained in newest Libera Brilliance software Release 2.0, no hardware changes are needed. The measurement principles and first measurements with results are presented.
LANL, Los Alamos, New Mexico
Funding: US DOE
The Compact Reconfigurable Input/Output (cRIO) hardware manufactured by National Instruments (NI) is evaluated as a wire scanner motion controller. This particular configuration utilizes a NI cRIO-9074 system combined with various C-series modules for wire scanner motion control I/O. Programs for this system have been written in LabVIEW and a majority of the motion-control functionality has been programmed into the cRIO's FPGA in order to provide the fastest motion control processing possible with cRIO. Additional topics of interest include, cRIO-based resolver-to-digital conversion and closed-loop, stepper-based motion control
SLAC, Menlo Park, California
Funding: Operated by Stanford University for the U. S. Department of Energy under Contract DE-AC02-76-SF00515 and Office of Basic Energy Sciences.
The Bergoz Instrumentation New Parametric Current Transformer (NPCT) has been evaluated at the SPEAR3 synchrotron light source. The device was tested for vacuum performance and residual gas and was found suitable for installation in the storage ring. The NPCT was installed during August 2008 and has measured beam currents to 500 mA. Performance is compared to the earlier PCT design. The NPCT Sensor Head has been instrumented with thermal sensors for characterization of the internal operating temperature.
USP/LAL, Sao Paulo
Funding: FAPESP, CNPq
In this work we describe a model to study the effect of charge saturation in phosphor screens in the determination of electron beam profiles. It is shown that the charge saturation introduces systematic errors in the beam diameter determination, since it tends to increase the observed beam diameter. The study is made supposing a Gaussian beam profile and a saturation model to the charge response of the phosphor material. The induced errors increase for higher currents and/or narrow beams. A possible correction algorithm that can be applied to some measurements is presented, together with a brief discussion about the consequences of these systematic errors in emittance measurements.
JLAB, Newport News, Virginia
Receivers designed for diagnostic applications range from those having moderate sensitivity to those possessing large dynamic range. Digital receivers have a dynamic range which are a function of the number of bits represented by the ADC and subsequent processing. If some of this range is sacrificed for extreme sensitivity, noise power can then be used to perform two-point load calibrations. Since load temperatures can be precisely determined, the receiver can be quickly and accurately characterized; minute changes in system gain can then be detected, and systematic errors corrected. In addition, using receiver pairs in a balanced approach to measuring X+, X-, Y+, Y-, eliminates systematic offset errors from non-identical system gains, and changes in system performance. This paper describes and demonstrates a balanced BPM-style diagnostic receiver, employing Dicke-switching to establish and maintain real-time system calibration. Benefits of such a receiver include wide bandwidth, solid absolute accuracy, improved position accuracy, and phase-sensitive measurements. System description, static and dynamic modeling, and measurement data are presented.
CERN, Geneva
A series of LHC injection tests was performed in August and September 2008. The first saw beam injected into sector 23; the second into sectors 78 and 23; the third into sectors 78-67 and sectors 23-34-45. The fourth, into sectors 23-34-45, was performed the evening before the extended injection test on the 10th September which saw both beams brought around the full circumference of the LHC. The tests enabled the testing and debugging of a number of critical control and hardware systems; testing and validation of instrumentation with beam for the first time; deployment, and validation of a number of measurement procedures. Beam based measurements revealed a number of machine configuration issues that were rapidly resolved. The tests were undoubtedly an essential precursor to the successful start of LHC beam commissioning. This paper provides an outline of preparation for the tests, the machine configuration and summarizes the measurements made and individual system performance.
SLAC, Menlo Park, California
R.W. Downing Inc., Tucson
Funding: US Department of Energy Contract DE AC03 76SF00515.
The ILC R&D electronics program at SLAC includes development of key technologies aimed at improving reliability and availability and reducing cost. This paper discusses the development of high availability interlocks and controls for the L-Band high power RF stations. A new Fast Fault Finder (F3) VME module has been developed to process both slow interlocks using FPGA logic to detect the interlock trip excursions. This combination eliminates the need for separate PLC control of slow interlocks with modules chained together to accommodate as many inputs as needed. Next a high availability platform demonstration will port the F3’s via a specially designed VME adapter module into the new industry standard ATCA[1] crate (shelf). This high-availability platform features an Intelligent Platform Management (IPMI) system to control and monitor the health of the entire system, provide redundancy as needed for the application, and demonstrate auto-failover and hot-swap to minimize MTTR. The goal is to demonstrate “five nines” (0.99999) system availability at the shelf level. A new international initiative, the xTCA for Physics Standards Working Group, will be briefly mentioned.
[1] Advanced Telecom Computing Architecture
Sigmaphi, Vannes
CEA, Gif-sur-Yvette
LPSC, Grenoble
The paper presents the magnetic measurements of the RACCAM prototype FFAG dipole, manufactured by SIGMAPHI for the Raccam ANR Medical FFAG project. This magnet prototyping work, started early 2006, is being performed in collaboration between the IN2P3/LPSC Laboratory team and SIGMAPHI. This paper describes the magnetic measurement results and comparison with Tosca simulation.