BNL, Upton, Long Island, New York
The Faraday Cup Award is given for an outstanding contribution to the development of an innovative particle beam diagnostic instrument of proven workability. It is presented at the Beam Instrumentation Workshop (BIW), a biennial forum for in-depth discussions of techniques for measuring particle beams produced in accelerators. This session will present the latest Faraday Cup winner, and the Proceedings article associated with it will summarize the history of the award. After the award is presented, this year's honoree (a secret until the Workshop) will give a talk on the design and performance of the winning instrument. For more information on the Award, see http://www.faraday-cup.com.
CERN, Geneva
The diamond beam monitor is a solid-state ionization chamber that stands out due to its fast and efficient charge collection and its high radiation tolerance. The diamond technology gives a charge collection time of less than 1 ns and lifetime studies made at CERN with 24 GeV protons showed a decrease in performance of only 50% at 10 MGy, which make this device particularly well adapted to applications in particle accelerators. A poly-crystalline CVD diamond beam monitor has been evaluated as a beam halo loss monitor for the CERN LHC accelerator. Despite the read-out being made through 250 m of cable, the tests showed a good signal-to-noise ratio of 6.8, an excellent double-pulse resolution of less than 5 ns and a high dynamic range basically unlimited except by the electronics. A single-crystalline CVD diamond beam monitor was built and tested in cooperation with Bergoz Instrumentation for ISOLDE at CERN for the HIE-REX upgrade. This device was used to measure the beam intensity for particle counting and for measuring the beam energy spectrum. An energy resolution of 0.6% and a time resolution of 39 ps were measured for a carbon ion energy of 22.8 MeV.
ZTEC Instruments, Albuquerque
Modular oscilloscopes and digitizers, including those with embedded EPICS IOCs, provide powerful off-the-shelf solutions for accelerator controls and beamline data acquisition applications requiring fast sampling, high resolution and/or tight multi-channel synchronization. This presentation discusses features and capabilities of EPICS and non-EPICS LXI, VXI, PXI and PCI oscilloscopes and digitizers as they specifically relate to accelerator and beamline applications. Modular oscilloscopes and digitizers with on-board DSP and FPGAs provide the advanced waveform acquisition and analysis capabilities of benchtop instruments with the size and channel-density advantages of modular instruments. Instruments with on-board processing, such as those from ZTEC Instruments, enable real-time waveform math and waveform parameter analysis. Advanced triggering and multiple acquisition modes are other features found on some of today’s advanced modular instruments. Furthermore, instruments with embedded EPICS IOCs save users the time and money of developing their own EPICS drivers and display panels. Examples of specific accelerator applications using advanced modular instruments will be presented.
National Instruments, Austin
Since 1976, National Instruments (NI) has taken off-the-shelf semiconductor and computing technology and applied it to measurement, diagnostics and instrumentation needs. NI leverages the rapid technological advancement of the semiconductor and computer industry, while retaining the flexibility and ensuring interoperability between HW & SW. This technical session will focus on the various models of computation, multicore technology applied to measurement and diagnostic needs, communication protocols, timing and synchronization, and FPGA designed-in to meet custom needs. Additionally we will see examples of Graphical System Design being applied at CERN, Max Planck, LANL, ESO and how COTS HW & SW technologies can be used to solve instrumentation needs.
LANL, Los Alamos, New Mexico
The goal of the design LANSCE-R Wire-Scanner Analog Front-end Electronics is to develop a high-performance, dual-axis wire-scanner analog front-end system implemented in a single cRIO module. This new design accommodates macropulse widths as wide as 700 us at a maximum pulse rate of 120 Hz. A lossey integrator is utilized as the integration element to eliminate the requirement for providing gating signals to each wire scanner. The long macropulse and the high repetition rate present conflicting requirements for the design of the integrator. The long macropulse requires a long integration time constant to assure minimum integrator droop for accurate charge integration, and the high repetition rate requires a short time constant to assure adequate integrator reset between macropulses. Also, grounding is a serious concern due to the small signal levels. This paper reviews the basic Wire Scanner AFE system design implemented in the cRIO-module form factor to capture the charge information from the wire sensors and the grounding topology to assure minimum noise contamination of the wire signals.
I-Tech, Solkan
SOLEIL, Gif-sur-Yvette
Libera Photon is the new Photon Beam Position Processor (PBPM) from the Instrumentation Technologies. First measurements on real beam have been done at SOLEIL Synchrotron. The module was connected to a PBPM installed on the DIFFABS bending magnet beam line. Three different beam position experiments were done: measurement of position at beam bump (± 500 μm), beam current dependence and filling pattern dependence. Measurements were done with internal BIAS voltage source set to -70 V. Measured current was in the range up to 250 μA on the sensor. Measurements were done on standard 100 kS/s, 10 kS/s and 10 S/s data flows with different bandwidths. The article discusses the results and consequential improvements of the device.
BNL, Upton, Long Island, New York
Two most widely used BPM systems (manufactured by Bergoz and Instrumentation Technologies) implement switching technique to eliminate drifts caused by change in a channel gain. High stability is achieved by an alternative routing of signals from all pick-up electrodes through the same chain. In this paper we propose a different approach of separating signals in the frequency domain, which is based on advances of digital signal processing allowing identical gains for the separate frequencies. Experimental set-up and results are presented. Practical realization of the beam position monitors is also discussed.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
The introduction of Silicon Photomultipliers (SiPMs) as single photon sensitive detectors represents a promising alternative to traditional photomultiplier tubes. This is especially true in applications in which it is compulsory to attain magnetic field insensitivity, low photon flux detection, quantum efficiency in the blue region that is comparable to standard photomultipliers, high timing resolution, dimensions comparable to the dimensions of an optical fiber diameters, and low costs. The structure of the SiPM is based on an array of independent avalanche photodiodes (APDs) working in Geiger-mode at a low bias voltage with a high gain. The output signal is proportional to the number of pixels "fired" by impacting photons. The detection efficiency for state-of-the-art devices is in the order of 20% at 500 nm. In this contribution, the measured dark count rates of different SiPMs are compared and the influence of this noise on the real signal is presented. These results are then used to correct the photon count and determine the optimized working parameters for a future beam loss monitor at CTF3/CLIC.
NewPath, Salt Lake City, Utah
We have derived algebraic expressions for the open-circuit voltage that is induced on a Rogowski coil, having imperfectly spaced turns, by a time-dependent current which passes through the aperture of the coil. The derivation of these expressions requires that the layer of the winding is thin, the number of turns is large, and the cross-section of the winding is uninform and rectangular. Examples are given in which these expressions are applied to determine the effects of the gap between the ends of the coil, as well as other irregularities in the spacing of the turns, on the position sensitivity–defined as the dependence of the induced voltage on the coordinates of the current. The results in these examples agree with those that others have obtained by numerical methods or measurements with Rogowski coils. This technique may be used to quickly define the design specifications which are required to satisfy a specific upper limit for the positional sensitivity.
NewPath, Salt Lake City, Utah
Others have shown that the voltages induced on one uniformly-wound toroidal coil and two sinusoidally-wound toroidal coils may be used to determine the current in a single filament and its coordinates. We have extended this technique to show that the voltages measured on a group of sinusoidally-wound toroidal coils may be used to approximate the distribution of current within their common aperture. This is possible because each measured voltage is proportional to the product of unique functions of the radial and azimuthal coordinates of each increment of the current [1,2]. We have developed matrix methods to determine the transverse distribution of the current and determined the sensitivity of these calculations to measurement errors. Shielded sinusoidally-wound coils with a precision of 0.02 cm have been prepared using rapid prototyping, and methods have been defined to prepare the next generation of these coils, which will have a precision of 0.001 cm, by using an engraving tool with the 4th axis of a vertical milling machine.
I-Tech, Solkan
ESRF, Grenoble
The lifetime of the electron beam in a Synchrotron Light Source is an important parameter. Its precise measurement within a short time is an essential tool to evaluate properties and stability of a storage ring. In some cases, for example during short gas outbursts in the UHV vacuum chamber leading to rapid lifetime drops, it can be used as a useful diagnostic tool as well. Traditionally, dedicated PCTs (Parametric Current Transformers) are mostly used for this purpose. The idea to use Libera Brilliance Beam Position Processor instead came after the excellent quality of its sum signal was observed. Moreover, the measurement accuracy is greatly increased by averaging the lifetime measurements of all the individual stations, bearing in mind that there are typically more than hundred BPMs positioned around the ring. First measurements were performed on ESRF, showing very good performance potential. The article discusses the measurements, their results, the comparison with more classical methods, and the implementation of this feature in the Libera Brilliance software.
CERN, Geneva
A high resolution beam position monitor (BPM) electronics based on diode peak detectors has been developed at CERN. The circuit processes the BPM electrode signals independently, converting the short beam pulses into slowly varying signals which are digitized with high resolution ADCs operating in the kHz range. For large enough amplitudes the non-linear forward voltage of the diodes is compensated by a simple network using signals from single-diode and double-diode peak detectors. This contribution discusses the performance of the built prototype with beam in the CERN-SPS and comments on possible future applications of the technique.
CERN, Geneva
The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from over 4,000 monitors, and has nearly 3 million configurable parameters. In a system of such complexity, firmware reliability is a critical issue. The integrity of the signal chain of the LHC BLM system and its ability to correctly detect unwanted scenarios and thus provide the required protection level must be ensured. In order to analyze the reliability and functionality, a test bench has been developed that emulates different types of loss signals and monitors the performance and response of the FPGA-based data analysis firmware. This paper will report on the numerous tests that have been performed and on how the results are used to quantify the reliability of the system.
Agilent Technologies SA, Plan-les-Ouates
Agilent Technologies Inc., Loveland
Digital data acquisition in real time applications falls into two categories: digitizing a stream of data without missing a single sample point, and capturing a stream of triggered events without missing a single trigger. Maintaining these data streams over long periods requires an optimized combination of analog signal conditioning, and precise digitization, digital data reduction and high-speed data transfer. This paper describes suggested methods to reduce the amount of measurement data required, reduce the amount of that data that is to be transferred (to a measurement where possible), and then transfer this reduced data in the most rapid fashion. Our approach uses a combination of hardware, firmware and software elements that are designed to work together, optimizing performance and managing the data bottlenecks. New hardware standards and architectures are discussed that improve the capabilities of today's technologies, providing access to higher data and measurement flux. Applications presented in this paper include high trigger rate capture for beam steering and fill pattern monitoring in charged particle accelerators.
LANL, Los Alamos, New Mexico
In a nutshell, the role of a beam diagnostic measurement is to provide information needed to get a particle beam from Point A (injection point) to Point B (a target) in a useable condition, meaning with the right energy and size and with acceptable losses. Specifications and performance requirements of diagnostics are based on the physics of the particle beam to be measured, with typical customers of beam parameter measurements being the accelerator operators and accelerator physicists. This tutorial will be a physics-oriented discussion of the interplay between tuning evolutions and the beam diagnostics systems that support the machine tune. This will include the differences between developing a tune and maintaining a tune, among other things. Practical longitudinal and transverse tuning issues and techniques from a variety of proton and electron machines will also be discussed.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
DITANET is the largest-ever EU funded training network in beam diagnostics. The network members – universities, research centres and industry partners – are developing diagnostics methods for a wide range of existing or future particle accelerators, both for electron and for ion beams. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes schools and topical workshops for the beam instrumentation community. This contribution gives an overview of the Network's research portfolio, summarizes the main research results from the first two years of DITANET and presents past and future training activities.