| Paper | Title | Page |
|---|---|---|
| MOPC102 | RF and Surface Properties of Superconducting Samples | 310 |
|
||
|
Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF) The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since Rs varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. It is shown how different contributions to the surface resistance depend on temperature, applied RF magnetic field and frequency. Furthermore, measurements of the maximum RF magnetic field as a function of temperature and frequency in pulsed and CW operation are presented. The study is accompanied by measurements of the surface properties of the samples by various techniques. |
||
| MOPS082 | Some Considerations on the Choice of Frequency and Geometrical Beta in High Power Proton Linacs in the Context of Higher Order Modes | 793 |
|
||
| Several high power superconducting (SC) proton linear accelerators are currently in the design stage around the world, such as for example the European Spallation Source (ESS) in Lund, Project X at Fermilab, the European ADS demonstrator MYRRAH in Mol and the Superconducting Proton linac (SPL) at CERN. In this contribution, the influence of Higher Order Modes (HOMs) in elliptical SC cavities is discussed as a function of the operation frequency, the number of cells and the geometrical beta of the cavity. Based on cavity design data beam dynamics simulations are executed for different linac layouts to quantify the influence of HOMs. | ||
| TUPC048 | First Measurement Results of the LHC Longitudinal Density Monitor | 1105 |
|
||
|
Funding: The primary author is funded by the E.U. under the DITANET Marie Curie network. Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, for example to check the injection quality and to characterize the development of ghost bunches before and during the physics periods. A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions. The LDM is able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved. The LDM operated during the 2010 lead ion run and during 2011 with protons. Measurements from both runs are presented in this contribution along with an analysis of the LDM performance and an outlook for future upgrades. |
||
| TUPC083 | Comparative Studies into 3D Beam Loss Simulations | 1198 |
|
||
|
Funding: Work supported by the Helmholtz Association and GSI under contract VH-NG-328. A detailed understanding and monitoring of potential beam loss mechanisms is crucial for every particle accelerator. The main motivation in low energy facilities, such as the Ultra-low energy Storage Ring (USR) at the future Facility of Low energy Antiproton and Ion Research (FLAIR), comes from the very low number of particles available which in such machine ought to be conserved. In High Energy accelerators it is the concern about activation or even physical damage of machine parts which has to be taken into serious account. The CLIC Test Facility (CTF3) at CERN provides an ideal testing ground for studies into novel BLM systems and is well suited for benchmarking the results from numerical simulations in experiments. This contribution summarizes the three-dimensional beam loss pattern as found with the commonly used codes FLUKA and Géant4. The results from these codes are compared and analyzed in detail and used for the identification of optimum beam loss monitor locations. |
||
| TUPC153 | Study of the Response of Silicon Photomultipliers in Presence of Strong Cross-talk Noise | 1389 |
|
||
|
Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328. Silicon Photomultipliers (SiPM) are interesting detectors for beam diagnostics applications where they could replace photomultiplier tubes as large dynamic range photon counting devices due to their reduced dimensions and costs, higher photon detection efficiency, immunity to magnetic fields and low operation voltage. Possible applications include longitudinal beam profile measurements by synchrotron light imaging, detection of optical transition radiation for energy spectrum measurements and medical imaging. However, quantitative measurement with SiPMs are jeopardized by the systematic reading error due to Optical Cross-talk (OC), i.e. optical coupling between neighboring diodes in the array. OC results in overestimation of the impinging light level, and reflects the probability of a triggered avalanche creating a photon of suitable energy and direction to fire a second avalanche in another diode. In this paper, we derive a generalized response distribution for SiPM in presence of cross-talk noise, which overcomes the limitations of assumptions currently made in literature and provides a correction of the SiPM response distribution valid for arbitrary large levels of cross-talk. |
||
| TUPC154 | Commissioning of the Detection System for a Supersonic Gas-jets Based Transverse Beam Profile Monitor | 1392 |
|
||
|
Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328. We present the commissioning results of the Micro-Channel-Plate (MCP) based, ion extraction and detection system currently in use for an experimental test stand aimed at demonstrating the operation of a least-interceptive transverse beam profile monitor based on a planar supersonic gas-jet. This monitoring design features least-interceptive operation under excellent vacuum conditions and provides fast acquisition of a fully bi-dimensional transverse profile. It bears application for ultra-low energy particle beams at future storage rings, but also for e.g. linacs at high currents and light source injectors. For instance, the Ultra-low energy Storage Ring (USR), part of the Facility for Antiproton and Ion Research (FAIR) in Germany will store antiprotons at energies of 20-300 keV. In this contribution, we report numerical simulations and experimental results obtained by calibration of the detection system with a low energy electron beam to demonstrate a 1 mm imaging resolution only limited by recoiling ion drift. |
||
| TUPC162 | Thin Foil-based Secondary Emission Monitor for Low Intensity, Low Energy Beam Profile Measurements | 1413 |
|
||
|
Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328. A secondary emission monitor (SEM) was developed for beam profile measurements at the Ultra-low energy Storage Ring (USR) that will be installed at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) in Darmstadt, Germany. The detector consists of an Aluminium foil on negative potential, a grounded mesh placed in front of the foil, a chevron type microchannel plate (MCP), a phosphor screen and a camera connected to a PC. Simulations of the optimized design together with experimental results with keV protons are presented in this contribution. In addition, the usability of the detector for low energy antiproton beam profile measurements is discussed. |
||
| TUPC163 | Experimental Results from Test Measurements with the USR Beam Position Monitoring System | 1416 |
|
||
|
Funding: Work supported by STFC, the EU under GA-ITN-215080, the Helmholtz Association and GSI under VH-NG-328. A diagonal-cut capacitive pick-up (PU) was optimised for monitoring slow (v < 0.025c), long (~1 m) bunches consisting of only about 106 antiprotons at the future Ultra-low energy Storage Ring (USR). Ultra-low noise (0.5 nV/Hz0.5) FET pre-amplifiers are used to allow detection of the weak signals generated in the PU plates. The amplified signals are then digitized by a 16-bit, 200 MS/s ADC and processed in a digital manner. The following contribution presents the beam monitoring system as it was tested with a stretched-wire method and compares the measurements with the results from 3D electromagnetic simulations. |
||
| TUPC165 | DITANET - Investigations into Accelerator Beam Diagnostics | 1422 |
|
||
|
Funding: Work supported by the EU under GA-PITN-215080. DITANET is a Marie Curie initial 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 and particle accelerator communities. This contribution gives an overview of the Network's research outcomes to date and summarizes past and future training activities. |
||
| TUPC166 | Accelerator R&D in the QUASAR Group | 1425 |
|
||
|
Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Associations and GSI under VH-NG-328. Since its start in 2007, the QUASAR Group’s research activities have grown considerably: Whilst the research program towards an ultra-low energy storage ring (USR) at the future facility for low-energy antiproton and ion research (FLAIR) is still the main research focus, developments of beam diagnostics tools for accelerators and lights sources, investigations into superconducting linear accelerators and medical applications, including the potential use of antiproton beams for cancer therapy purposes, widen the Group’s activities and international collaboration considerably. An overview of the QUASAR Group’s research achievements in accelerator science and technology to date is given in this contribution. |
||
| WEPC009 | Design of an Antiproton Injection and Matching Beam Line for the AD Recycler Ring | 2019 |
|
||
|
Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328. A small antiproton recycler ring (AD-Rec) for use in the MUSASHI beamline at the CERN AD has been designed by the QUASAR Group for operation at energies between 3 and 30 keV. A highly efficient beam line for capturing the beam after extraction from the trap, transporting and injecting it into the AD Rec is very important to minimize losses and full the ring up to its space charge limit. In this contribution, the beam optical and mechanical design of the injector is presented. |
||
| WEPC010 | Investigations into Efficient Extraction and Acceleration of Beams from Ion Traps | 2022 |
|
||
|
Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG.328 A number of exotic ion species, such as for example radioactive isotopes or antiprotons, are highly desirable at very low energies of some tens of keV for fundamental studies. In order to obtain cooled beams with low emittance and low momentum spread, these particles are often first captured in an ion trap, cooled and then extracted and accelerated before being used in experiments. The extraction mechanism and subsequent beam handling impacts critically on the final beam quality. In this contribnution, an optimized scheme for efficient beam extraction and acceleration from ion traps is presented. Field maps from different existing ion trap setups, such as for example the Musashi trap at CERN, are used as a basis for simulation studies into the beam dynamics. Input and final beam emittances are analyzed as a function of the extraction and acceleration field geometries and the performance of different possible scenarios is directly compared. |
||
| WEPC064 | Long Term Beam Dynamics in Ultra-Low Energy Storage Rings | 2166 |
|
||
|
Funding: "Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328." Electrostatic storage rings operate at very low energies in the tens of keV range and have proven to be invaluable tools for atomic and molecular physics experiments. However, earlier measurements showed strong limitations in beam intensity, a fast reduction in the stored ion current, as well as significantly reduced beam life time at higher beam intensities and as a function of the ion optical elements used in the respective storage ring. In this contribution, the results from studies with the computer code BETACOOL into the long term beam dynamics in such storage rings, based on the examples of ELISA, the AD Recycler and the USR are presented. |
||
| WEPC065 | Design of a Low Energy Ion Beam Facility* | 2169 |
|
||
|
Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Association and GSI under VH-NG-328. A small electrostatic ring, and associated electrostatic injection beamlines, are being designed and developed. The ring will make possible a variety of experiments using a choice of many types of recirculating ions (e.g., from protons, H-, and antiprotons up to and including large charged biomolecules). A reaction microscope will be incorporated into the ring to enable differential ionization experiments between the recirculating ion beam and gas jet targets. Two injection sections have been designed to cover a variety of ion sources. The facility will be portable to enable it to be moved between facilities and beamlines and it will be unique due to its combination of design elements, flexible beam properties, energy (ca 3-30 keV) and type of circulating particles. In this paper, we give an update on this project. |
||
| WEPC162 | Investigations into Non-linear Beam Dynamics in Electrostatic Storage Rings | 2361 |
|
||
|
Funding: Work supported by STFC, the Helmholtz Association and GSI under contract VH-NG-328. Electrostatic (ES) storage rings provide a cost-effective solution to the problem of confining low energy (beta << 1) charged particles and ions, whilst controlling the beam properties, for use in multi-pass experiments. However, compared to magnetic storage rings, the beam dynamics calculations for an ES ring show subtle differences, especially in the coupling of the longitudinal and transverse velocities and in the focusing properties of bending element fringe fields. Using the nominal design for a prototype ES ring, realistic trajectories (including fringe fields and non-linear field components) have been calculated and a comparison is made with linear lattice simulations. The effect of the non-linear field components on the beam parameters is discussed. |
||
| WEPC171 | Requirements of a Beam Loss Monitoring System for the CLIC Two Beam Modules | 2385 |
|
||
| he Compact Linear Collider (CLIC) study investigates the feasibility of a high-energy electron-positron linear collider optimized for a centre of mass energy of 3 TeV. To achieve the high accelerating gradients, the RF power is produced by a novel two-beam acceleration method in which a decelerating drive beam supplies energy to the main accelerating beam. The linacs are arranged in modular structures referred to as the two beam modules which cover 42 km of beamline. Beam losses from either beam can have severe consequences due to the high intensity drive beam and the high energy, small emittance main beam. This paper presents recent developments towards the design of a Cherenkov fiber BLM system and discusses its ability to distinguish losses originating from either beam. | ||
| TUPC165 | DITANET - Investigations into Accelerator Beam Diagnostics | 1422 |
|
||
|
Funding: Work supported by the EU under GA-PITN-215080. DITANET is a Marie Curie initial 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 and particle accelerator communities. This contribution gives an overview of the Network's research outcomes to date and summarizes past and future training activities. |
||
| TUPC166 | Accelerator R&D in the QUASAR Group | 1425 |
|
||
|
Funding: Work supported by STFC, the EU under GA-PITN-215080, the Helmholtz Associations and GSI under VH-NG-328. Since its start in 2007, the QUASAR Group’s research activities have grown considerably: Whilst the research program towards an ultra-low energy storage ring (USR) at the future facility for low-energy antiproton and ion research (FLAIR) is still the main research focus, developments of beam diagnostics tools for accelerators and lights sources, investigations into superconducting linear accelerators and medical applications, including the potential use of antiproton beams for cancer therapy purposes, widen the Group’s activities and international collaboration considerably. An overview of the QUASAR Group’s research achievements in accelerator science and technology to date is given in this contribution. |
||