| Paper | Title | Page |
|---|---|---|
| MOPMR027 | Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements | 296 |
| SUPSS073 | use link to see paper's listing under its alternate paper code | |
|
||
|
Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed**, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed.
* LHCb collaboration, Journal of Instrumentation, 9, P12005 ** P. Hopchev in Proc. of IPAC 2014, June 15-20, 2014, Dresden Germany |
||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR027 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| MOPMR031 | Investigation of Injection Losses at the Large Hadron Collider with Diamond Based Particle Detectors | 310 |
|
||
| During the operation of the Large Hadron Collider (LHC) in 2015, increased injection losses were observed. To minimize stress on accelerator components in the injection regions of the LHC and to guarantee an efficient operation these losses needed to be understood and possible mitigation techniques should be studied. Measurements with diamond particle detectors revealed the loss structure with ns-resolution for the first time. Based on these measurements, recaptured beam from the Super Proton Synchrotron (SPS) surrounding the nominal bunch train was identified as the major contributor to the injection loss signals. Methods to reduce the recaptured beam in the SPS were successfully tested and verified with the diamond particle detectors. In this paper the detection and classification of LHC injection losses are described. The methods to reduce these losses and verification measurements are presented and discussed. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR031 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPMB052 | High Intensity Beam Test of Low Z Materials for the Upgrade of SPS-to-LHC Transfer Line Collimators and LHC Injection Absorbers | 1218 |
|
||
| In the framework of the LHC Injector Upgrade (LIU) and High-Luminosity LHC (HL-LHC) project, the collimators in the SPS-to LHC transfer lines will undergo important modifications. The changes to these collimators will allow them to cope with beam brightness and intensity levels much increased with respect to their original design parameters: nominal and ultimate LHC. The necessity for replacement of the current materials will need to be confirmed by a test in the High Radiation to Materials (HRM) facility at CERN. This test will involve low Z materials (such as Graphite and 3-D Carbon/Carbon composite), and will recreate the worst case scenario those materials could see when directly impacted by High luminosity LHC (HL-LHC) or Batch Compression Merging and Splitting (BCMS) beams. Thermo-structural simulations used for the material studies and research, the experiment preparation phase, the experiment itself, pre irradiation analysis (including ultrasound and metrology tests on the target materials), the results and their correlation with numerical simulations will be presented. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB052 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPMR027 | CERN's Fixed Target Primary Ion Programme | 1297 |
|
||
| The renewed availability of heavy ions at CERN for the needs of the LHC programme has triggered the interest of the fixed-target community. The project, which involves sending several species of primary ions at various energies to the North Area of the Super Proton Synchrotron, has now entered its operational phase. The first argon run, with momenta ranging from 13 AGeV/c to 150 AGeV/c, took place from February 2015 to April 2015. This paper presents the status of the project, the performance achieved thus far and an outlook on future plans. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR027 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPMR050 | Upgrades to the SPS-to-LHC Transfer Line Beam Stoppers for the LHC High-Luminosity Era | 1367 |
|
||
| Each of the 3 km long transfer lines between the SPS and the LHC is equipped with two beam stoppers (TEDs), one at the beginning of the line and one close to the LHC injection point, which need to absorb the full transferred beam. The beam stoppers are used for setting up the SPS extractions and transfer lines with beam without having to inject into the LHC. Energy deposition and thermo-mechanical simulations have, however, shown that the TEDs will not be robust enough to safely absorb the high intensity beams foreseen for the high-luminosity LHC era. This paper will summarize the simulation results and limitations for upgrading the beam stoppers. An outline of the hardware upgrade strategy for the TEDs together with modifications to the SPS extraction interlock system to enforce intensity limitations for beam on the beam stoppers will be given. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR050 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPMR051 | New Spill Control for the Slow Extraction in the Multi-Cycling SPS | 1371 |
|
||
| The flux of particles slow extracted with the 1/3 integer resonance from the Super Proton Synchrotron at CERN was previously controlled with a servo-spill feedback system which acted on the horizontal tune such as to keep the spill rate as constant as possible during the whole extraction time. The current in two servo-quadrupoles was modulated as a function of the difference between the measured and the desired spill rate. With servo quadrupoles at a single location in the SPS ring and the SPS in multi-cycling mode, the trajectory of the slow extracted beam was seen to change from cycle to cycle depending on the current applied by the servo feedback. Hence this system was replaced by a feed-forward tune correction using the main SPS quadrupoles. In this way the spill control can now be guaranteed without changing the trajectory of the extracted beam. This paper presents the algorithm and implementation in the control system and summarizes the advantages of the new approach. The obtained spill characteristics will be discussed. The technique implemented for the additional reduction of the 50 Hz noise on the spill structure will also be briefly outlined. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR051 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUPMR052 | Commissioning Preparation of the AWAKE Proton Beam Line | 1374 |
|
||
| The AWAKE experiment at CERN will use a proton bunch with an momentum of 400 GeV/c from the SPS to drive large amplitude wakefields in a plasma. This will require a ~830 m long transfer line from the SPS to the experiment. The prepa- rations for the beam commissioning of the AWAKE proton transfer line are presented in this paper. They include the detailed planning of the commissioning steps, controls and beam instrumentation specifications as well as operational tools, which are developed for the steering and monitoring of the beam line. The installation of the transfer line has been finished and first beam is planned in summer 2016. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR052 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPOR048 | Beam Losses at CERNs PS and SPS Measured with Diamond Particle Detectors | 3898 |
|
||
| Diamond particle detectors have been used in the LHC to measure fast particle losses with a nanosecond time resolution. In addition, these detectors were installed in the PS and the SPS. The detectors are mounted close to the extraction septum of the PS (transfer line to SPS) and the SPS (transfer lines TI2 and TI8 to LHC). Mainly, they monitor the losses occurring during the extraction process but the detectors are also able to measure turn-by-turn losses in the accelerators. In addition, detailed studies concerning losses due to ghost bunches were performed. This paper will describe the installed diamond detector setup, discuss the measurement results and possible loss mitigations. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR048 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPOR052 | A Beam-based Measurement of the LHC Beam Dump Kicker Waveform | 3911 |
|
||
| The increase of the LHC collision energy to 13 TeV after Long Shutdown 1 has doubled the operational energy range of the LHC beam dump system (LBDS) during Run 2. In preparation for the safe operation of the LHC, the waveform of the LBDS extraction kicker was measured using beam-based measurements for the first time during the machine's re-commissioning period. The measurements provide a reference for a more precise synchronisation of the dump system and abort-gap timing, and provide an independent check of the system's calibration. The precision of the beam-based technique allowed the necessary adjustments to the LBDS trigger delays to ensure the synchronous firing of the LBDS at all beam energies up to 6.5 TeV. In this paper the measurement and simulation campaign is described and the performance of the system reported. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR052 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPOR054 | Analysis of the SPS Long Term Orbit Drifts | 3914 |
|
||
| The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain, and has to deliver the two high-intensity 450 GeV proton beams to the LHC. The transport from SPS to LHC is done through the two Transfer Lines (TL), TI2 and TI8, for Beam 1 (B1) and Beam 2 (B2) respectively. During the first LHC operation period Run 1, a long term drift of the SPS orbit was observed, causing changes in the LHC injection due to the resulting changes in the TL trajectories. This translated into longer LHC turnaround because of the necessity to periodically correct the TL trajectories in order to preserve the beam quality at injection into the LHC. Different sources for the SPS orbit drifts have been investigated: each of them can account only partially for the total orbit drift observed. In this paper, the possible sources of such drift are described, together with the simulated and measured effect they cause. Possible solutions and countermeasures are also discussed. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR054 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPOR055 | Characterisation of the SPS Slow-extraction Parameters | 3918 |
|
||
| The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain but its main users are the fixed-target experiments located in the North Area (NA). The beams, which are among the most intense circulating in the SPS, are extracted to the NA over several thousands of turns by exploiting a third-integer resonant extraction. The unavoidable losses intrinsic to such an extraction makes its optimisation one of the main priorities for operation, to reduce beam induced activation of the machine. The settings of the extraction systems, together with the tune sweep speed and the beam characteristics (momentum spread, emittance, etc.) are the parameters that can be controlled for spill and loss optimisation. In this paper, the contribution of these parameters to the slow-extraction spill quality are investigated through tracking simulations. The simulation model is compared with beam measurements and optimisations suggested. | ||
| DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR055 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |