Beam Profile Monitor Research Articles

Online full two-dimensional imaging of pulsed muon beams at J-PARC MUSE using a gated image intensifier

A new muon beam profile monitor (MBPM) was developed to diagnose pulsed muon beams at J-PARC MUSE, mainly composed of a scintillation screen, a gated image intensifier (II), and a cooled CCD camera. The MBPM was designed to be compact so that it could be inserted into the bore of the μSR spectrometer in the D1 area and used concurrently. The spatial resolution of the MBPM was evaluated to be better than 1.4mm, depending on the II gain. Such high-resolution muon beam profiles were obtained online for a positive muon beam with a kinetic energy of approximately 4MeV. The contribution from the decay positrons to beam profiles was significantly reduced owing to the II gating. The linearity of the MBPM was evaluated on the basis of the number of decay positrons monitored by the μSR spectrometer. A linear response within a deviation of ±5% was confirmed over more than two orders of magnitude. In addition, a 3D imaging capability, used in vacuum, and immunity against moderate magnetic fields were demonstrated.

Investigations into beam monitors at the AE g ̄ $\bar {g}$ IS experiment

Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE $\bar {g}$ IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE $\bar {g}$ IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented.

Beam Diagnostics for Measurements of Antiproton Annihilation Cross Sections at Ultra-low Energy

The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antipro- tons) collaboration of CERN is currently attempting to measure the antiproton-nucleus in-flight annihilation cross sections on thin target foils of C, Pd, and Pt at 130 keV of kinetic energy. The low-energy antiprotons were supplied by the Antiproton Decelera- tor (AD) and a radio-frequency quadrupole decelerator. For this measurement, a beam profile monitor based on secondary electron emission was developed. Data from this monitor was used to ensure that antiprotons were precisely tuned to the position of an 80- mm-diameter experimental target, by measuring the spatial profile of 200-ns-long beam pulses containing 10 5 10 6 antiprotons with an active area of 40 mm 40 mm and a spa- tial resolution of 4 mm. By using this monitor, we succeeded in finely tuning antiproton beams on the target, and observed some annihilation events originating from the target.

Spatial Resolution Test of a Beam Profile Monitoring System for the Double Electrostatic Ion Storage Ring

A beam profile monitoring system based on the imaging of low energy electrons created when the ion beam impinges on a metal plate was built to monitor the beam profile and to cover the wide range of beam intensities and energies for the DESIREE (Double ElectroStatic Ion Ring ExpEriment) beam line diagnostics. The spatial resolution of the system was tested with different beams of various energies and was found to be around 2 mm. A significant steering effect on the ion beam before hitting the metallic foil was observed at low energies.

The beam diagnostic instruments in Beijing radioactive ion-beam facilities isotope separator on-line

The beam diagnostic instruments for Beijing Radioactive Ion-beam Facilities Isotope Separator On-Line are introduced [B. Q. Cui, Z. H. Peng, Y. J. Ma, R. G. Ma, B. Tang, T. Zhang, and W. S. Jiang, Nucl. Instrum. Methods 266, 4113 (2008); T. J. Zhang, X. L. Guan, and B. Q. Cui, in Proceedings of APAC 2004, Gyeongju, Korea, 2004, http://www.jacow.org, p. 267]. For low intensity ion beam [30-300 keV/1 pA-10 μA], the beam profile monitor, the emittance measurement unit, and the analyzing slit will be installed. For the primary proton beam [100 MeV/200 μA], the beam profile scanner will be installed. For identification of the nuclide, a beam identification unit will be installed. The details of prototype of the beam diagnostic units and some experiment results will be described in this article.

Fluctuation of an ion beam extracted from an AC filament driven Bernas-type ion source

Argon ion beam fluctuation from an AC filament driven Bernas-type ion source is observed. The ion beam was measured by an 8 measurement elements beam profile monitor. The amplitude of the beam current fluctuation stayed in the same level from 100 Hz to 1 kHz of the filament heating frequency. The beam current fluctuation frequency measured by the beam profile monitor was equal to the frequency of the AC filament operation. The fluctuation amplitudes of the beam current by AC operation were less than 7% and were in the same level of the DC operation.

A real-time intercepting beam-profile monitor for a medical cyclotron

There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.

Residual gas fluorescence monitor for relativistic heavy ions at RHIC

A residual gas fluorescence beam profile monitor at the Relativistic Heavy Ion Collider (RHIC) has successfully recorded beam images of various species of relativistic heavy ions during FY2012 operations. These fully striped ions include gold, copper, and uranium at 100, 99.9, and $96.4\text{ }\text{ }\mathrm{GeV}/\mathrm{n}$, respectively. Their beam profiles give an independent measurement of the RHIC beam size and emittance. We estimated their corresponding fluorescence cross sections to be $2.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$, $1.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$, and $2.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}\text{ }\text{ }{\mathrm{cm}}^{2}$, and obtained their rms transverse beam sizes of 0.36, 0.37, 0.24 mm for gold, copper, and uranium ions, respectively. They are the smallest ion beam width, thus lowest beam emittance, ever produced at RHIC or any other high-energy heavy ion colliders. These extremely small beam sizes may have reached a fundamental limit to residual gas fluorescence based beam profile monitor. Nevertheless, this beam diagnostic technique, utilizing the beam-induced fluorescence from residual gas where hydrogen is still the dominant constituent in nearly all vacuum systems, represents a passive, robust, truly noninvasive, monitor for high-energy ion beams.

Beam profile monitoring at the test beam line at the Compact Linear Collider test facility

Following the discovery of the Higgs-like boson at the Large Hadron Collider, there is demand for precision measurements on recent findings. The Compact Linear Collider, CLIC, is a candidate for a future linear electron-positron collider for such precision measurements. In CLIC, the beams will be brought to collisions in the multi-TeV regime through high gradient acceleration with high frequency RF power. A high intensity electron beam, the so-called drive beam, will serve as the power source for the main beam, as the drive beam is decelerated in special structures, from which power is extracted and transfered to the main beam. When the drive beam is decelerated the beam quality deteriorates and the momentum spread increases, which makes the beam transport challenging. Dedicated diagnostics to monitor the momentum profile along each bunch train and transverse profile diagnostics will be needed to guarantee the reliability of the decelerator and consequently the power source of the main beam acceleration.A test facility, CTF3, has been constructed at CERN to validate key technical aspects of the CLIC concept. The beam quality in the decelerator will be investigated in the test beam line, TBL, where several power extraction structures reduce the drive beam energy by up to 55%. At the same time, the single-bunch rms energy spread grows from the initial value of 1% to almost 6%. To monitor the parameters of such a beam is challenging but crucial for the optimization of the beamline. In this thesis we report on progress made on adapting generally used methods for beam profile measurements to the demanding conditions of a wide momentum profile. Two detector technologies are used for measuring transverse profile and momentum profile and we discuss the performance of these instruments, in the view of the large momentum spread and with the outlook towards equivalent beam profile monitors in the CLIC decelerator.

Comprehensive method to analyze thick insulating samples using PIXE technique

In this work, we present a new method to analyze thick insulating samples by PIXE technique. The method is based on the use of both an electron flood gun to compensate the charge build-up at the insulating surface and a beam profile monitor (BPM) to provide a precise indirect measurement of the beam current and accumulated charge. A filament extracted from an ordinary flashlight lamp was used as an electron flood gun. While, a commercial BPM has been adapted in order to carry out charge measurements. The results have revealed the convenience of using BPM for measuring the charge in PIXE measurements. The use of the electron flood gun has given very satisfactory results in term of preventing charge build-up and reducing its contribution to the bremsstrahlung background in the PIXE spectra. The applicability and efficiency of the overall system for elemental analysis were successfully verified using IAEA-Soil-7 reference material where both accuracy and precision were found to be better than 10% in most cases.

Visible-light beam size monitors using synchrotron radiation at CESR

A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500μm can be measured with a resolution of approximately 5μm. To measure larger beam size (>500μm), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the π-polarized component of SR, a small vertical beam size (∼70μm) was measured during an undulator test run in CESR, which was consistent with the interferometer measurement. To measure the bunch length, a beam splitter is inserted to direct a fraction of light into a streak camera setup. This beam size monitor measures the transverse and longitudinal beam sizes simultaneously, which is successfully used for intrabeam scattering studies. Detailed error analysis is discussed.

Short and long term ionizing radiation effects on charge-coupled devices in radiation environment of high-intensity heavy ion accelerators

Radiation effects on semiconductor devices is a topical issue for high-intensity accelerator projects. In particular it concerns Charge-Coupled Device (CCD) cameras, which are widely used for beam profile monitoring and surveillance in high radiation environment. One should have a clear idea of short and long term radiation effects on such devices. To study these effects, a CCD camera was placed in positions less than half meter away from beam loss point. Primary heavy ion beam of 0.95GeV/n Uranium was dumped into a thick aluminium target creating high fluences of secondary particles (e.g., gammas, neutrons, protons). Effects of these particles on CCD camera were scored with LabView based acquisition software. Monte Carlo calculations with FLUKA code were performed to obtain fluence distributions for different particles and make relevant comparisons. Long term total ionising dose effects are represented by dark current increase, which was scored throughout experiment. Instant radiation effects are represented by creation of charge in CCD cells by ionising particles. Relation of this charge to beam intensity was obtained for different camera positions and fluences within 5 orders of magnitude ranges. With high intensities this charge is so high that it may dramatically influence data obtained from CCD camera used in high radiation environment. The linearity of described above relation confirms linear response of CCD to ionizing radiation. It gives an opportunity to find a new application to CCD cameras as beam loss monitors (BLM).

A new beam profile monitor and time of flight system for CologneAMS

A complex beam detector consisting of a high-resolution beam profile monitor (BPM) and a time of flight (TOF) spectrometer with tracking capabilities was designed especially for the special needs of the Cologne center for accelerator mass spectrometry (CologneAMS). The beam detector assembly is designed to match the beam specifications of the 6MV Tandetron AMS setup and its data acquisition system. It will have a reconfigurable structure, either as a fast TOF subsystem with a ca. 10cm2 equivalent active area, or as a more complex BPM–TOF detector with beam tracking capabilities and a larger active area (16cm2). The purpose of this detector is to suppress background during spectrometry of heavy ions (U, Cm, Pu, Am etc.) and to suppress isobaric interferences such as 36S in 36Cl spectra.

Beam instrumentation for the Ultra-low energy Storage Ring (USR)

The electrostatic Ultra-low energy Storage Ring (USR) at the future Facility for Low energy Antiproton and Ion Research (FLAIR) will make available antiprotons from 300 keV down to 20 keV beam energy. This multipurpose machine puts challenging demands on the beam instrumentation due to the varied bunch structure (ultra-short bunches of 1–2 ns up to a quasi-DC beam structure on the other), together with variable very low beam energies, ultra-low currents of down to 1 nA (or even less in the transfer lines which means less than 2 × 107 particles). Thus, the development of new diagnostic devices is required as most of the standard techniques are not suitable. Within the QUASAR Group, the necessary beam instrumentation for the commissioning phase and standard operation of the USR, as well as advanced techniques such as a gas curtain-jet beam profile monitor, have been developed and prototypes of all devices have been built up. This paper presents the design of all beam diagnostics devices for the USR and summarizes the results from first measurements.

Beam profile monitor for antiproton-nucleus annihilation cross section measurements

The ASACUSA (the Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration is planning to measure the antiproton-nucleus annihilation cross sections at kinetic energy 120 keV on targets of various mass numbers (C, Ni, Sn, and Pt) using the Antiproton Decelerator (AD) of CERN. No previous measurement exists in this region where the A-dependence of this cross section is expected to deviate from the A(2/3) as reported by the Obelix collaboration. For this measurement, a beam profile monitor based on secondary electron emission with a grid of electrode pads fabricated on an FR4-type glass-epoxy circuit board was developed. The advantage of this detector is that it is simple, lightweight, and low cost. It was used to measure the spatial profile of 100-ns-long beam pulses containing > 6 × 104 antiprotons with an active area of 40 mm × 40 mm and a spatial resolution of 4 mm.

串列加速器电离性束流截面探测器设计

串列加速器电离性束流截面探测器设计

Beam profile monitor for annihilation cross section measurements of antiprotons at 100 keV

The ASACUSA (the Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration is planning to measure the cross sections of antiproton annihilations at kinetic energy 100 keV on targets of various mass numbers (C, Ni, Sn, and Pt) using the Antiproton Decelerator (AD) of CERN. No previous measurement exists in this region where the A-dependence of the cross section is expected to deviate from the A\(^{\frac{2}{3}}\) (Batty et al, Nucl Phys A 689:721, 2001) as reported by the Obelix collaboration. A beam profile monitor based on secondary electron emission with a grid of electrode pads fabricated on an FR4-type glass-epoxy circuit board was developed for this measurement. The advantage of this kind of detector is that it is simple, lightweight, and low cost. It was used to measure the spatial profile of 100-ns-long beam pulses containing > 6 × 104 antiprotons with an active area of 40 mm × 40 mm and a spatial resolution of 4 mm.

Development of Beam Profile Monitor for Antiproton Annihilation Cross Section Measurements by the ASACUSA Collaboration

The ASACUSA (the Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration has developed various kinds of monitors which both destructively and non-destructively measure the spatial profiles of pulsed antiproton beams at the Antiproton Decelerator (AD) of CERN. These include detectors consisting of foil and wire electrodes based on gas ionization or secondary electron emission, which are compatible with ultra-high vacuum conditions. A new beam profile monitor with a grid of electrode pads fabricated on a normal glass-epoxy circuitboard was adapted for the measurement of antiproton annihilation cross sections. This monitor has an active area of 40 mm × 40 mm and a spatial resolution of 4 mm. It can measure the spatial profile of 40-50-ns-long beam pulses containing > 104 antiprotons striking each anode strip.

Synchrotron radiation based beam diagnostics at the Fermilab Tevatron11Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.

Synchrotron radiation has been used for many years as a beam diagnostic at electron accelerators. It is not normally associated with proton accelerators as the intensity of the radiation is too weak to make detection practical. However, if one utilizes the radiation originating near the edge of a bending magnet, or from a short magnet, the rapidly changing magnetic field serves to enhance the wavelengths shorter than the cutoff wavelength, which for more recent high energy proton accelerators such as Fermilab's Tevatron, tends to be visible light. This paper discusses the implementation at the Tevatron of two devices. A transverse beam profile monitor images the synchrotron radiation coming from the proton and antiproton beams separately and provides profile data for each bunch. A second monitor measures the low-level intensity of beam in the abort gaps which poses a danger to both the accelerator's superconducting magnets and the silicon detectors of the high energy physics experiments. Comparisons of measurements from the profile monitor to measurements from the flying wire profile systems are presented as are a number of examples of the application of the profile and abort gap intensity measurements to the modelling of Tevatron beam dynamics.

Development of a Neutral Beam Profile Monitor

We developed a novel beam profile monitor for measuring the shape of an intense neutral beam for particle physics. This monitor is based on a detector technology of scintillating fibers, photomultiplier tubes, and sampling ADCs. It has an advantage for its simplicity, reliability, flexibility, and versatility. This monitor was installed in the small-diameter neutral beam for the KL0 →π0 νν experiment at J-PARC. We report in this article the development and performance of this monitor.