CERN, Geneva
Linac 4 is the injector upgrade currently under construction at CERN to improve luminosity and reliability for the whole accelerator chain. This machine will include about 120 high-gradient, 20 mm aperture Halbach-array permanent quadrupoles (PMQ) housed in the Drift Tube tanks, as well as about 80 electromagnetic quadrupoles (EMQ) with power cycles approx. 2 ms long. This paper is concerned with the magnetic measurements carried out at CERN on the first batch of PMQ, including several prototypes from different manufacturers, as well as those done on several spare Linac 2 EMQs reused in Linac 4's 3 MeV test stand. We first describe the test setup, focusing our attention on a prototype test bench based on technology developed for the LHC and able to carry out high-precision harmonic measurements in both continuously-rotating and stepping-coil mode (FAME*). Next we present the results obtained in terms of integral field strength and quality, with special emphasis on the analysis of very fast eddy current transients in the EMQs. Finally, we discuss the expected impact of these findings on the operation of the machine.
* N. R. Brooks et al, "Estimation Of Mechanical Vibration Of The LHC Fast Magnetic Measurement System", IEEE Transactions on Applied Superconductivity, vol. 18, No. 2 , 2008.
CERN, Geneva
Force transducers based on strain and capacitive gauges have been developed and used for monitoring the coil pre-stress during assembly and excitation of magnet models. This paper will summarize and compare the new techniques of mechanical measurements use at CERN for the New Inner Triplet Project. Furthermore the paper will give a comparison of the gauge performances (Creep effects, temperature effects, etc.) and will present the performances of the new data acquisition system developed at CERN to measure simultaneously the strain gauges, the capacitive gauges and other external parameters for the magnet.
Muons, Inc, Batavia
North Carolina State University, Raleigh, North Carolina
Magnet applications for high energy physics has long been an important driver for the development of superconducting technology. New high temperature superconductors (HTS), which have very high values of the upper critical field Hc2, show promise for magnets generating fields greater than 25 T, such as those required for muon cooling [1]. (Rare Earth)Ba2Cu3Oy (REBCO) coated conductor is an HTS material which is well suited to these needs; however it requires characterization in the low temperature (4.2 K), high magnetic field regime. We are proposing to measure electro-mechanical and magnetic properties, including angular field dependence of commercially available REBCO conductor. Here we present results of initial testing to characterize commercially available REBCO coated conductors at 77 K, including critical current and quench testing to calculate minimum the quench energy (MQE) and normal zone propagation velocity (NZPV).
LBNL, Berkeley, California
Fermilab, Batavia
BNL, Upton, Long Island, New York
Advanced superconductors such as Nb3Sn are being considered for future magnet upgrades of the Large Hadron Collider (LHC) at CERN. The US LHC Accelerator Research Program (LARP) has developed a large bore (120mm) Nb3Sn IR quadrupole (HQ) capable of reaching 15 T at its conductor and a gradients of 199T/m at 4.4K and 219T/m at 1.9K. HQ is addressing coil alignment and accelerator field quality in a shell-based mechanical structure. In this paper we summarize the fabrication, assembly and initial test results of the 1 m long two-layer magnet.
KEK, Ibaraki
LBNL, Berkeley, California
Osaka University, Osaka
OXFORDphysics, Oxford, Oxon
Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with ~2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.
CERN, Geneva
After the incident on the 19th September 2008 and more than one year without beam the commissioning of the LHC started again on November 20, 2009. Progress was rapid and collisions under stable beam conditions were established at 1.2 TeV within 3 weeks. In 2010 after qualification of the new quench protection system the way to 3.5 TeV was open and collisions were delivered at this energy after a month of additional commissioning. This paper describes the experiences and issues encountered during these first periods of commissioning with beam.
CERN, Geneva
The first LHC shut-down started in fall 2008, just after the incident on the 19th of September 2008. In addition to the typical work of a shut-down, a large number of interventions, related to the 'consolidation after the incident' were performed in the LHC loop. Moreover the amount of work increased during the shut-down, following the recommendations and conclusions of the different working groups in charge of the safety of the personnel and of the machine. This paper will give an overview of the work performed, the organization of the coordination, emphasizing the new safety risks (electrical and cryogenic), and how the interventions were implemented in order to ensure both the safety of personnel and a minimized time window.
YerPhI, Yerevan
The Vibrating Wire Monitor (VWM) with aperture 20 mm was developed for scan of electron beam with large transversal sizes. Test experiments with VWM placed in air were done on the 20 MeV electron beam of Yerevan Synchrotron Injector with 4-7 uA at outlet. A new design of VWM is proposed for scan of the beam with even greater transversal sizes.
FZJ, Jülich
UniDo/IBS, Dortmund
GSI, Darmstadt
JINR, Dubna, Moscow Region
To study electron cooling in a synchrotron nondestructive methods only are suitable. The ionization profile monitor (IPM) delivers real-time data in both transverse planes allowing detailed analysis of beam profile evolution in COSY. First attempts to use scintillation of residual gas (SPM) to measure beam profiles were very promising. Beam diagnostics based on recombination is usually used to optimize electron cooling of protons (H0-diagnostics). However, it is not available when cooling antiprotons. So the IPM and possibly the SPM are vital for electron cooling optimization in the HESR ring. The new beam instrumentation at COSY is introduced and its relevance for the new 2 MeV electron cooler project and the HESR are discussed. Results of beam studies performed during electron cooling beam times at COSY are presented.
I-Tech, Solkan
PSI, Villigen
Measurements were performed at the Swiss Light Source on the beamline X06SA using a four-quadrant CVD diamond sensor which was connected to Libera Photon, a new photon BPM device from Instrumentation Technologies. The outputs of the sensor are 4 current signals in the nA range and are directly connected to the measuring unit without any pre-amplifiers. External bias voltage was applied, although the Libera Photon can supply internal bias voltage. Measurements consisted of: scanning the measurement range, frequency analysis of the beam movement and analysis of the photon beam flux influence on the measured position. The Sensor was mounted on a motorized XY stepper motor stage. Acquired data consisted of raw signal amplitudes and processed positions. Acquisitions were taken at 10 kHz and 10 Hz rate.
CERN, Geneva
CERN's Large Hadron Collider (LHC) is equipped with three distinct types of intensity measurement systems: total intensity measurement using DC transformers (DCCTs) with a bandwidth up to a few kHz; total intensity measurements on a turn-by-turn basis for lifetime measurements using AC-coupled fast transformers (fast BCTs); bunch-by-bunch intensity measurements with a bandwidth up to a few hundred MHz also using the fast BCTs. In addition to providing intensity information these devices are part of the machine protection system, indicating whether or not there is beam circulating, transmitting intensity for evaluation of safe beam conditions and capable of triggering a beam dump if fast losses are detected. This paper reports on the commissioning of all these systems and their initial performance.
ZTEC Instruments, Albuquerque
Off-the-shelf instruments based on the LAN eXtensions for Instrumentation (LXI) standard that include embedded EPICS input/output controllers (IOCs) are an ideal solution for many particle accelerator applications. These applications require responsive remote control and real-time waveform monitoring for critical accelerator systems including machine protection, beam position monitoring and others. These instruments have the same feature sets and powerful analysis capabilities that today's high-end benchtop instruments have. With an embedded EPICS controller, the instruments easily integrate into the EPICS environment without the need for EPICS drivers or external controllers. They can be controlled and monitored by EPICS applications such as EDM and MEDM. These EPICS oscilloscopes and digitizers perform advanced real-time waveform math and analysis using on-board FPGAs and DSP. The paper will detail how ZTEC Instruments' EPICS oscilloscopes are being used at facilities around the world for real-time control and monitoring via EPICS.
ANL, Argonne
The Advanced Photon Source (APS) is a third-generation synchrotron light source in the United States. The BPM electronics plays an important part in the beam stability control. This paper presents comparative measurements of two BPM electronics: Libera Brilliance and APS FPGA-based BSP100. Some important parameters such as beam current dependence, electronics resolution and fill pattern dependence have been measured. These measurements were carried out in the lab and in the real system. The results will be useful for deciding which BPM electronics to deploy in the APS upgrade project.
CERN, Geneva
The UA9 experiment was installed in the CERN-SPS in March '09 in view of investigating crystal assisted collimation in coasting mode. Inside a vacuum vessel, two 2 mm long silicon crystals, bent by about 150 microradians are mounted on accurate goniometers, and a small 10mm long tungsten target is used to compare the effect of crystals with that of a standard scatterer. A moveable 60 cm long block of tungsten is located downstream at about 90 degrees phase advance to intercept the deflected beam. Scintillators, gas GEMs and beam loss monitors measure nuclear loss rates induced by the interaction of the halo beam in the crystal itself. A Roman pot is installed in the path of the deflected particles in between the crystal and the collimator, equipped with a Medipix detector to reconstruct the transverse spot of the impinging beam. Finally UA9 takes advantage of an LHC-collimator prototype installed close to the Roman pot to help in setting the beam conditions and to reveal in a destructive manner the deflected beam shape. This paper describes in details the hardware installed, and the procedures developed to set-up and detect the channeling conditions.
JASRI/SPring-8, Hyogo-ken
This presentation will cover the topics of synchrotron radiation monitors for light sources, including transverse beam profile measurement, longitudinal bunch profile measurement, and bunch purity measurement. It will also cover developments of beam diagnostics based on observation of x-rays from a dedicated insertion device.
I-Tech, Solkan
After LHC completion, maintenance and operation of the facility provide a good opportunity for accelerator industry in Europe. Other big facilities like XFEL, FAIR, FERMI@ELETTRA and MAX IV are now under way. The challenges of the accelerator industry in Europe and its future outlook will be presented.
KEK, Ibaraki
VXI-11 is an industrial standard to control equipments through network. A moule to control these equipments through Python scripting Language was developed. This module can be used for quick testing of equipments and for the rapid application development. The implementation of the module will be discussed and some application of the module will be reported.
NSRRC, Hsinchu
To enhance waveform and spectrum remote access supports in the Taiwan Light Source (TLS), development of the EPICS support of Ethernet-based oscilloscope and spectrum analyzer for the TLS is under way. The EPICS platforms which built to interface these instruments could access the waveform and spectrum through the PV (Process Variable) channel access. By using remote operations of waveform and spectrum acquisition, long distance cabling could be eliminated and signal quality be improved. The EDM (Extensible Display Manager) tool is used to implement the operation interface of control console and provide waveform display. According to specific purpose use, different graphical user interfaces to integrate waveform and spectrum acquisition are built. This project is the preparation for future control room integration with the Taiwan Photon Source control room. The efforts will be described at this report.
University of Ljubljana, Faculty of Electrical Engineering, Ljubljana
I-Tech, Solkan
The new generation of accelerators requires timing distribution and RF synchronization with femtosecond precision in terms of jitter and long-term stability. The proposed electro-optical synchronization system makes use of commercial telecom single-mode optical fibre operating at 1550 nm.. It operates on over 300 m distance. It consists of a transmitter, located near a low-jitter master oscillator, and receiver, located at the remote location. The field experiments have been done in the accelerator environment with the fibre pair in the tunnel. The prototype units were installed at the same location to make phase difference measurement simple. Temperature in various installation points, phase difference and both units internal operational parameters were continuously monitored and stored. Data was post-analysed and conclusions were used for hardware changes and mostly the long-term stability improvement. A dedicated phase detector was designed to monitor less than 20 fs changes. Results are showing 80 fs RMS and 30 fs stability over 20 and 8 hours respectively. The prototype is being redesigned for manufacturing with some new features for improved long-term stability.
SLAC, Menlo Park, California
Superconducting RF is increasingly important for particle accelerators. A lot of effort has been made in the SRF material research recently, aiming to find the superconducting materials with better performance. We developed a testing system using a resonant cavity with high quality factor and an interchangeable wall for the testing of different materials. The system is capable for high power RF cryogenic test to find the critical magnetic field at different temperature. The facility can be also used on testing the low temperature properties of the normal conducting material. Different Cu, Nb and MgB2 samples have been tested. In this paper, we will present the most recent development of the system, along with a discussion on the recent testing results.
CIEMAT, Madrid
CERN, Geneva
The goal of the present CLIC test facility (CTF3) is to demonstrate the technical feasibility of the CLIC scheme. The Test Beam Line (TBL) is used to study a CLIC decelerator focusing on 12 GHz power production and the stability of the decelerated beam. The extracted CTF3 drive beam from the combiner ring (CR) features a maximum intensity of 28 A and 140 ns pulse duration, where the Test Beam Line consists of 16 cells, each one including a BPM, a quadrupole on top of a micrometer-accuracy mover and a RF power extractor so-called PETS (Power Extraction and Transfer Structure). This paper describes the first prototype fabrication techniques, with particular attention to the production of the long copper rods which induce the RF generation. A special test bench for the characterization of the device with low RF power measurements has been developed. Performed mesurements of the scattering parameters and the electric field profile along the structure are carefully described. Finally, the prototype has been installed at CLEX, and first measurements with beam are also reported.
Fermilab, Batavia
IIT, Chicago, Illinois
LBNL, Berkeley, California
ANL, Argonne
BNL, Upton, Long Island, New York
JLAB, Newport News, Virginia
TThe MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. This paper will give an overview of the program, which will include a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field which allows for a more detailed study of the maximum stable operating gradient vs. magnetic field strength and angle.
KEK, Ibaraki
Hitachi Technologies and Services Co., Ltd., Kandatsu, Tsuchiura
Two superconducting crab cavities were successfully installed into the KEKB accelerator in January 2007. Since then the crab cavities have been in stable operation for 3 years up to now, thanks to reliable operation of the cryogenic system of the KEKB including a large-scale helium refrigerator. This means that the cryostat for the crab cavities was well designed and constructed properly, although there are some technical complexities in the cryostat, such as two helium vessels in a cryostat, a movable coaxial coupler which is cooled with liquid helium and so on. The KEKB cryogenic system was also appropriately modified to operate the two crab cavity cryostats stably. This cryogenic system is described in this presentation. A calorimetric method to measure the Q-factors of the crab cavities is suggested, which employs an electric compensation heater in the cryostat, instead of the conventional method, which measures the descending rate of liquid helium level. Measurement results of the Q-factors of crab cavities after being assembled in the cryostat and after being installed into the KEKB accelerator are compared with the vertical test results.
CERN, Geneva
The High Radiation to Materials facility - thereafter HiRadMat - is designed to allow testing of accelerator components, in particular those of the LHC and its injectors, with the impact of high-intensity pulsed beams. The facility is currently under construction, as an approved CERN project. The installation of the dedicated primary beam line and experimental area is planned during the 2010-2011 CERN accelerator technical shutdown. It will be ready for users after commissioning and some initial running in October 2011. A detailed proton beam line design has been performed in order to fulfill the beam parameter specification, in particular the demanding optics flexibility at the test stand location. The studies presented include trajectory correction and aperture studies as well as specifications of magnetic systems, power converters, beam instrumentation and vacuum systems.