MC4: Hadron Accelerators
T12 Beam Injection/Extraction and Transport
Paper Title Page
WEPMP003 Beam Dynamics and Diagnostics for the High Energy Beam Transport Line of MINERVA Project at SCK•CEN 2304
SUSPFO008   use link to see paper's listing under its alternate paper code  
 
  • H. Kraft, L. Perrot
    IPN, Orsay, France
 
  Funding: French research agency and technologies (ANRT), through the program CIFRE (2018/0080 ) supported by THALES AVS FRANCE SAS.
MYRRHA will be a research infrastructure highlighted by the first prototype of a sub-critical nuclear reactor driven by a 600 MeV particle accelerator (ADS). This project aims at exploring the transmutation of long-lived nuclear wastes. A first phase is planned to validate the reliability of a 100 MeV/4 mA Protons LINAC carrying the beam toward an ISOL facility, prefiguring the real MYRRHA demonstrator at 600 MeV. This project is called MINERVA. This paper presents the status of the beam dynamic studies for the high energy beam transport lines at 100 MeV. In agreement with the project require-ments, we describe the specificities of these beam lines for which it is needed to implement a fast kicker-septum. This system will separate the beam between two main lines: toward the beam dump or the ISOL facility. We also describe the studies on the Beam Position Monitor (BPM) selected for MYRRHA. Part of this work was sup-port by the MYRTE project of the European Union.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP003  
About • paper received ※ 24 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP005 Beam Line Optimization Using Derivative-Free Algorithms 2307
 
  • S. Appel, S. Reimann
    GSI, Darmstadt, Germany
 
  The present study focuses on the beam line optimization from the heavy-ion synchrotron SIS18 to the HADES experiment. BOBYQA (Bound Optimization BY Quadratic Approximation) solves bound constrained optimization problems without using derivatives of the objective function. The Bayesian optimization is an other strategy for global optimization of costly, noisy functions without using derivatives. A python programming interface to MADX allow the use of the python implementation of BOBYQA and Bayesian method. This gave the possibility to use tracking simulation with MADX to determine the loss budget for each lattice setting during the optimization and compare both optimization methods.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP005  
About • paper received ※ 29 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP007 Current Status of Slow Extraction from J-PARC Main Ring 2311
 
  • R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, M. Okada, K. Okamura, T. Shimogawa, Y. Shirakabe, M. Tomizawa, T. Toyama, E. Yanaoka
    KEK, Ibaraki, Japan
  • A. Matsumura
    Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan
 
  A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP007  
About • paper received ※ 01 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP008 A Consideration on the Transfer Function Between RQ Field and Slow Extraction Spill in the Main Ring of J-Parc 2315
 
  • K. Okamura, Y. Arakaki, S. Murasugi, R. Muto, Y. Shirakabe, M. Tomizawa, E. Yanaoka
    KEK, Ibaraki, Japan
  • T. Kimura
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer reso-nant extraction and delivered to the hadron experimental facility. Increasing the duty of beam spill is one of the important issues in the slow extraction system. In the MR, the spill feedback system utilizing a digital signal processor (DSP) combined with EQ and RQ magnet is used to smooth the spill, where EQ defines a rough out-line of the slow extraction shape and RQ is used for the ripple cancelling. In this study, frequency domain charac-teristics between the current of RQ magnet and the beam spill was investigated by driving the RQ magnet with sinusoidal current, so that the transfer function from the current of RQ magnet to the spill signal is delivered.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP008  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP010 8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC 2322
 
  • M. Tomizawa, Y. Arakaki, Y. Fukao, Y. Hashimoto, Y. Igarashi, T. Kimura, S. Mihara, M. Moritsu, S. Murasugi, R. Muto, H. Nishiguchi, K. Okamura, Y. Shirakabe, K. Ueno, E. Yanaoka
    KEK, Ibaraki, Japan
  • Y. Fujii
    Monash University, Faculty of Science, Clayton, Victoria, Australia
  • F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
 
  A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10-10. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP010  
About • paper received ※ 01 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP011 Residual Orbits Estimation of the Injection Painting Bumps for CSNS 2326
 
  • M.Y. Huang, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
 
  Funding: Work supported by National Natural Science Foundation of China (Project No. U1832210)
There are three bumps (one chicane bump and two painting bumps) in the injection system of the China Spallation Neutron Source (CSNS). They are the core parts of the injection system and the important guarantee that the Linac beam injecting into the rapid cycling synchrotron (RCS). During the beam commissioning, to check the effect of the residual orbits of the three bumps in the injection region was an important problem. In this paper, the residual orbits of BH and BV painting bumps were studied and estimated in the beam commissioning. The data analysis results showed that the residual orbits of BH and BV painting bumps were very small and they didn’t need to be corrected.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP011  
About • paper received ※ 01 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP012 Beam Loss and the Stripping Efficiency Measurement for CSNS Injection System 2329
 
  • M.Y. Huang, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
 
  Funding: Work supported by National Natural Science Foundation of China (Project No. U1832210)
The injection beam loss is the main beam loss of the rapid cycling synchrotron (RCS) for the China Spallation Neutron Source (CSNS). After the optimization of injection system during the beam commissioning, the current injection beam loss for CSNS/RCS is approximately 1%. There are several sources of injection beam loss. In order to distinguish these different sources, the stripping efficiency of the main stripping foil should be studied and measured accurately. In this paper, a scheme for the accurate measurement of the stripping efficiency for CSNS will be proposed and studied. It can not only reduce the injection beam loss, but also be used to estimate the operation state and lifespan of the main stripping foil accurately. This method will be applied in future beam commissioning.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP012  
About • paper received ※ 30 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP014 Slow Extraction Study by Using Sextupole 2332
 
  • L. Huang, S. Wang
    IHEP, Beijing, People’s Republic of China
 
  The spill continuously extracted from synchrotron by using resonance sextupoles plays a key role in multidisciplinary application. The intensity of virtual sextupole and the spiral step for the typical synchrotron are obtained theoretically. A customized synchrotron of extraction components placed in dispersion section is designed and the tracking code of slow extraction is developed, thus the theoretical spiral step is comparative studied. To study the beam loss, three layouts of extraction are also designed based on the synchrotron. The result shows that the beam losses at extraction point are different for three cases and it is advantage to beam loss for extraction components placed in dispersion-free straight section.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP014  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP020 First Beam Transmission Measurements in Ion Source and LEBT at the European Spallation Source 2353
 
  • E. Laface
    ESS, Lund, Sweden
 
  The Ion Source and the Low Energy Beam Transport (LEBT) have been installed in the European Spallation Source tunnel, in Lund, Sweden, during the summer 2018. The first proton beam was extracted on September. In this paper we present the first set of measurements of protons transmission in combination with the analysis of the species (H+, H+2, H+3) extracted by the source. We show that our measurements are compatible with a fraction of 80\% of protons transported along the LEBT, as measured at the INFN-LNS, Catania, Italy during the commissioning in 2016-17. [1]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP020  
About • paper received ※ 12 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP021 Frequency Modulated Capture of Cooled Coasting Ion Beams 2356
 
  • S.C.P. Albright, M.E. Angoletta
    CERN, Geneva, Switzerland
 
  Transverse space charge effects in the Low Energy Ion Ring (LEIR) at CERN have been shown to be a major source of particle losses, which can be mitigated with a larger RMS longitudinal emittance. However, due to electron cooling during the injection plateau, the longitudinal density is very high prior to RF capture. In addition there is an uncontrolled cycle to cycle variation in the revolution frequency of the coasting beam on the flat bottom, which degrades the beam quality at capture. In this paper we show that applying an RF frequency modulation during the capture process allows both a controlled blow-up of the longitudinal emittance and a very good reproducibility in the longitudinal distribution, which in turn improves beam transmission through the machine.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP021  
About • paper received ※ 29 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP022 Design and Construction of the CERN SPS Extraction Protection Elements for LIU 2359
 
  • B. Balhan, C. Baud, J.C.C.M. Borburgh, M.A. Fraser, M. Hourican, L.O. Jorat, F.-X. Nuiry, S. Pianese
    CERN, Geneva, Switzerland
 
  At CERN, the SPS synchrotron is equipped with two fast extraction channels towards the LHC. As a part of the LHC injector upgrade project (LIU), the protection devices upstream of the septa in both extraction channels will be upgraded. Various failure scenarios have been studied and presented in the past, but the definitive approach for the equipment protection upgrade for each channel has now been determined. This paper describes the consequences of the most significant failure scenarios and the impact of the heat deposition in the diluter. The resulting material stresses are evaluated. The detailed layout for the extraction protection equipment for each extraction channel is outlined. The final layout consists of a extended diluter in Long Straight Section (LSS) 6 (TPSG6) and the installation of an additional movable absorber (TPSC4) upstream of the quadrupole in front of the existing protection equipment in LSS 4. The detailed mechanical design of the TPSC4 and the construction status of both TPSC4 and TPSG6 are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP022  
About • paper received ※ 10 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP024 Alternative Material Choices to Reduce Activation of Extraction Equipment 2363
 
  • D. Björkman, B. Balhan, J.C.C.M. Borburgh, L.S. Esposito, M.A. Fraser, B. Goddard, L.S. Stoel, H. Vincke
    CERN, Geneva, Switzerland
 
  At CERN, the Super Proton Synchrotron (SPS) is equipped with a resonant slow extraction system in Long Straight Section 2 (LSS2) towards the fixed target (FT) beam lines in the North Area. The extraction region provides the physics experiments with a quasi-DC flux of high-energy protons over a few seconds, which corresponds to tens of thousands of turns. The resonant slow extraction process provokes beam losses and is therefore the origin of radiation damage and the production of induced radioactivity in this region of the machine. This induced radioactivity imposed high constraints on the equipment design to be reliable to minimise the radiation exposure to personnel during machine maintenance. A detailed FLUKA model was developed in order to better understand the beam loss patterns, activation of the machine and to identify equipment components that could be optimised to reduce the residual dose related hazards. Simulations identified multiple alternative materials for extraction equipment components as well as shielding locations, which implementation could reduce residual activation hazards.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP024  
About • paper received ※ 26 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP025 Matching Studies Between CERN PSB and PS Through Multi-Turn Beam Profile Acquisitions 2367
 
  • M.A. Fraser, Y. Dutheil, V. Forte, A. Guerrero, A. Huschauer, A. Oeftiger, S. Ogur, F. Roncarolo, E. Senes, F. Tecker
    CERN, Geneva, Switzerland
 
  In the framework of the LHC Injectors Upgrade (LIU) project, the investigation and quantification of the optics mismatch between the CERN Proton Synchrotron Booster (PSB) and PS is a crucial step in understanding the source of horizontal emittance growth between the two machines. Extensive studies were carried out to estimate the mismatch from single-pass measurements in the transfer line and to rematch the transfer line to reduce the dispersive mismatch at PS injection while keeping the betatron matching unaltered. This paper presents the results of the data analysis of more recent multi-turn measurements, which profited from a new turn-by-turn beam profile monitor in the PS ring, to assess the achieved level of matching and corresponding emittance growth. The results confirm the improved matching and demonstrate the feasibility of the multi-turn technique as a fundamental tool that will be important for the recommissioning of the renovated transfer line after Long Shutdown 2.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP025  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP026 Emittance Dilution from the CERN Proton Synchrotron Booster’s Extraction Kickers 2371
 
  • M.A. Fraser, S.C.P. Albright, F. Antoniou, G.P. Di Giovanni, Y. Dutheil, V. Forte, A. Huschauer, F. Roncarolo
    CERN, Meyrin, Switzerland
 
  Understanding the different sources of emittance dilution along the LHC injector chain is an important part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantify the transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS). In this contribution, the waveform measurement technique will be briefly outlined before the results and their implications for the LIU project and beam performance reach are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP026  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP027 Update on Beam Transfer Line Design for the SPS Beam Dump Facility 2375
 
  • Y. Dutheil, J. Bauche, L.A. Dougherty, M.A. Fraser, B. Goddard, C. Heßler, V. Kain, J. Kurdej, J.A. Uythoven, F.M. Velotti
    CERN, Geneva, Switzerland
 
  The SPS Beam Dump Facility (BDF) being studied as part of the Physics Beyond Colliders (PBC) CERN project has recently reached an important milestone with the completion of the comprehensive feasibility study. The BDF is a proposed fixed target facility to be installed in the SPS North Area, to accommodate experiments such as SHiP (Search for Hidden Particles), which is most notably aiming at studying hidden sector particles. This experiment requires a high intensity slowly extracted 400 GeV proton beam with 4·1013 protons per 1 s spill to achieve 4·1019 protons on target per year. The extraction and transport scheme will make use of the first 600 m of the existing North Area extraction line. This contribution presents the status of the design work of the new transfer line and discusses the challenges identified. Aperture studies and failure scenarios are treated and the results discussed. In particular, interlock systems aiming at protecting critical components against the uncontrolled loss of the high energy proton beam are considered. We also present the latest results and implications of the design of a new laminated Lambertson splitter magnet to provide fast switching between the current North Area experiments and the BDF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP027  
About • paper received ※ 13 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP028 Crystal for Slow Extraction Loss-Reduction of the SPS Electrostatic Septum 2379
 
  • L.S. Esposito, P. Bestman, M.E.J. Butcher, M. Calviani, M. Di Castro, M. Donzé, M.A. Fraser, M. Garattini, Y. Gavrikov, S.S. Gilardoni, B. Goddard, V. Kain, J. Lendaro, A. Masi, M. Pari, J. Prieto, R. Rossi, W. Scandale, R. Seidenbinder, P. Serrano Galvez, L.S. Stoel, F.M. Velotti, V. Zhovkovska
    CERN, Geneva, Switzerland
  • F.M. Addesa, F. Iacoangeli
    INFN-Roma, Roma, Italy
  • A.G. Afonin, Y.A. Chesnokov, A.A. Durum, V.A. Maisheev, Yu.E. Sandomirskiy, A.A. Yanovich
    IHEP, Moscow Region, Russia
  • J.E. Borg, M. Garattini, G. Hall, T. James, M. Pesaresi
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • A.S. Denisov, Y. Gavrikov, Yu.M. Ivanov, M.A. Koznov, L.G. Malyarenko, V. Skorobogatov
    PNPI, Gatchina, Leningrad District, Russia
  • F. Galluccio
    INFN-Napoli, Napoli, Italy
  • A.D. Kovalenko, A.M. Taratin
    JINR, Dubna, Moscow Region, Russia
  • F. Murtas
    INFN/LNF, Frascati, Italy
  • A. Natochii
    LAL, Orsay, France
 
  The use of a bent crystal was investigated in order to reduce the losses at the CERN Super Proton Synchrotron (SPS) electrostatic septa (ZS) during the slow extraction of 400 GeV protons toward the North Area. The crystal, installed a few meters upstream the ZS, bends protons that would otherwise impinge on the ZS wires. Since particle deflection with good efficiency is achieved only when the crystal lattice is aligned within ~10 urad to the trajectory of the particles (at p = 400 GeV/c), a compact goniometer was built to allow the correct angular alignment of the crystal with respect to the incoming beam with a precision of few urad. In this paper, we report on the crystal features measured during a dedicated beam test by the UA9 experimental installation in the CERN H8 beam line. Details of the goniometer and its installation are also reported. The first results achieved during dedicated Machine Development (MD) sessions are finally presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP028  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP030 LHC Injection Losses and Trajectories During Run 1 and 2 and Outlook to Injection of HL-LHC Beams 2387
 
  • W. Bartmann, C. Bracco, B. Goddard, F.M. Velotti, J. Wenninger
    CERN, Geneva, Switzerland
 
  The LHC turn-around time is impacted by the control of injection losses and trajectories. While shot-to-shot trajectory variations dominated the injection efficiency during LHC Run 1, several improvements of hardware and operational settings allowed for a high rate of successful injections during Run 2. Injection losses and trajectories are analysed and presented for the high intensity proton runs, as well as for different beam types used from the injectors. Based on this analysis, an outlook is shown for the HL-LHC era, where double the bunch intensity will have to be injected.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP030  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP031 SPS Slow Extraction Losses and Activation: Update on Recent Improvements 2391
 
  • M.A. Fraser, B. Balhan, H. Bartosik, J. Bernhard, C. Bertone, D. Björkman, J.C.C.M. Borburgh, M. Brugger, N. Charitonidis, N. Conan, K. Cornelis, Y. Dutheil, L.S. Esposito, R. Garcia Alia, L. Gatignon, C.M. Genton, B. Goddard, C. Heßler, Y. Kadi, V. Kain, A. Mereghetti, M. Pari, M. Patecki, J. Prieto, S. Redaelli, F. Roncarolo, R. Rossi, W. Scandale, N. Solieri, J. Spanggaard, O. Stein, L.S. Stoel, F.M. Velotti, H. Vincke
    CERN, Meyrin, Switzerland
  • D. Barna, K. Brunner
    Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
 
  Annual high intensity requests of over 1019 protons on target (POT) from the CERN Super Proton Synchrotron (SPS) Fixed Target (FT) physics program continue, with the prospect of requests for even higher, unprecedented levels in the coming decade. A concerted and multifaceted R&D effort has been launched to understand and reduce the slow extraction induced radioactivation of the SPS and to anticipate future experimental proposals, such as SHiP* at the SPS Beam Dump Facility (BDF)**, which will request an additional 4·1019 POT per year. In this contribution, we report on operational improvements and recent advances that have been made to significantly reduce the slow extraction losses, by up to a factor of 3, with the deployment of new extraction concepts, including passive and active (thin, bent crystal) diffusers and extraction on the third-integer resonance with octupoles. In light of the successful tests of the prototype extraction loss reduction schemes, an outlook and implications for future SPS FT operation will be presented.
* A. Golutvin et al., Rep. CERN-SPSC-2015-016 (SPSC-P-350), CERN, Geneva, Switzerland, Apr. 2015.
** M. Lamont et al., Rep. CERN-PBC-REPORT-2018-001, CERN, Geneva, Switzerland, 11 Dec 2018.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP031  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP032 Tracking Simulations of Shadowing Electrostatic Septum Wires by Means of Bent Crystals 2395
 
  • F.M. Velotti, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel
    CERN, Meyrin, Switzerland
 
  The Super Proton Synchrotron (SPS) slow extraction is a third integer resonant extraction and hence suffers from high losses at the electrostatic septum (ZS). This is one of the main limiting factors for the maximum number of Protons On Target (POT) deliverable from the SPS to the North Area (NA). A concept to significantly reduce the extraction losses via shadowing of the electrostatic septum wires using an upstream bent crystal has been proposed in *, predicting a loss reduction of up to 50% for the prototype system installed in 2018. Following the successful experimental demonstration of the concept with beam **, detailed tracking simulations have been performed to fully understand the results obtained. Further insights, such as the effective ZS width and its alignment, could be deduced by exploiting the response of the extraction loss as a function of the two degrees of freedom of the crystal (position and angle). In this paper, the beam dynamics simulations are discussed together with the implementation of the bent crystal into the simulation framework. A comparison with measurements is presented before proposals for new configurations and parameters are discussed.
* F.M. Velotti, et al., "Reduction of Resonant Slow Extraction Losses…", IPAC’18.
** F.M. Velotti, M.A. Fraser, et al., "Experimental SPS Slow Extraction Loss Reduction…", this conf.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP032  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP033 Slow Extraction Loss Reduction With Octupoles at the CERN SPS 2399
 
  • L.S. Stoel, H. Bartosik, M. Benedikt, M.A. Fraser, B. Goddard, V. Kain, F.M. Velotti
    CERN, Meyrin, Switzerland
 
  The powering of octupoles during third-integer resonant slow extraction has been studied and recently tested with beam at the CERN Super Proton Synchrotron (SPS) in order to increase the extraction efficiency and reduce the induced radioactivity of the extraction straight. The octupoles distort the particle trajectories in phase space in such a way that the extracted separatrix is folded, which decreases the particle density impinging the wires of the extraction septum at the expense of increasing the extracted beam emittance. During experimental SPS machine studies a reduction of over 40% in the specific (per extracted proton) beam loss measured at the extraction septum was demonstrated. In this paper, the prerequisite studies needed to safely but efficiently deploy the new extraction scheme in a limited time-frame are described, the experimental results are presented and an outlook is given towards the next steps to bring slow extraction with octupoles into routine operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP033  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP034 Characterisation of SPS Slow Extraction Spill Quality Degradation 2403
 
  • F.M. Velotti, H. Bartosik, M.C.L. Buzio, K. Cornelis, V. Di Capua, M.A. Fraser, B. Goddard, V. Kain
    CERN, Meyrin, Switzerland
 
  The main physics users of the Super Proton Synchrotron (SPS) are the experiments installed in the North Area (NA). They are supplied with slowly extracted protons or heavy ions, exploiting a third integer slow extraction to provide a 4.8 s spill. High duty cycle and constant particle flux are the main requirements. Frequent super cycle changes induce variation of the spill macro structure which directly deteriorate the final spill quality. In this paper, the source of such an effect are investigated. Results of both beam based measurements and direct magnetic measurements on the SPS reference magnets are presented. Finally, a possible strategy to counteract this effect is discussed, in order to try to remove the super cycle changes variation as cause for spill quality deterioration.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP034  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPMP035 Model and Measurements of CERN-SPS Slow Extraction Spill Re-Shaping - the Burst Mode Slow Extraction 2406
 
  • M. Pari, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
    CERN, Geneva, Switzerland
 
  The ENUBET ("Enhanced NeUtrino BEams from kaon Tagging") Project aims at reaching a new level of precision of the short-baseline neutrino cross section measurement by using an instrumented decay tunnel. The North Area (NA) experimental facility of the Super Proton Synchrotron (SPS) offers the required infrastructure for the experiment. A new slow extraction type, consisting of bursts of many consecutive millisecond spills within one macro spill, has been modeled and tested for the ENUBET Project. The burst-mode slow extraction has been tested for the first time at CERN-SPS, and MADX simulations of the process have been developed. In this paper the experimental results obtained during the test campaign are presented along with the results of the quality of the produced spill and comparing it with predictions from simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP035  
About • paper received ※ 12 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPMP038 Combined MCNP/Turtle Simulation of the SINQ Beam Line at PSI-HIPA 2410
 
  • D. Reggiani, D.C. Kiselev, M. Seidel, V. Talanov, M. Wohlmuther
    PSI, Villigen PSI, Switzerland
 
  With a nominal beam power of nearly 1.4 MW, the PSI High Intensity Proton Accelerator (HIPA) complex is currently at the forefront of the high intensity frontier of particle accelerators. A key issue of such facilities is the minimization of beam losses that could lead to excessive activation of beam line components. At HIPA, the SINQ beam line is particularly subject to relatively large losses since it receives the highly divergent beam scattered off a 40 or 60 mm thick muon production graphite target (TE). So far, for HIPA, beam line simulations have been carried out only by means of the matrix multiplication codes TRANSPORT and TURTLE. Although very efficient, such tools do not allow a precise determination of beam losses whenever targets and collimators are substantially affecting the beam optics. A true understanding of how beam halo and the low momentum tail contribute to the measured losses can only be achieved by complementing the traditional simulations techniques by a tool that can transport beam particles in different materials and, at the same time, handle complex geometries like the ones of collimators situated in the beam line. Moreover, such an improved beam line simulation would give a significant contribution in evaluating the feasibility of the SINQ beam rotation system currently under study. In this paper we present a simulation of the SINQ beam line combining MCNP models of TE and collimator sections with the TURTLE computation of the magnetic channel.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP038  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP044 Mu2e Electrostatic Septa Volumetric Exchange of Fc-40 Dielectric in High Radiation Environments 2434
 
  • M.L. Alvarez, A. Deshpande, K.R. Hunden, V.P. Nagaslaev, E. Pirtle
    Fermilab, Batavia, Illinois, USA
 
  Funding: * Operated by FRA, LLC under Contract No. DEAC02-07CH11359 and Grant Award No. LAB 18-1802 with the United States Department of Energy.
Two electrostatic septa (ESS) are being designed for the slow extraction of 8 GeV proton beam for the Mu2e experiment at Fermilab. Special attention is given to the high voltage feedthrough (HVF), which energizes the cathode creating the bending field. The FC-40 dielectric fluid, surrounding the HV cable breaks down from radiation exposure, which reduces its insulating capabilities. The new HVF design focuses on effective replacement of the exposed fluid and eliminating the stagnant areas of low exchange rate. A preliminary test using a fully transparent prototype HVF and water was conducted to understand the volumetric exchange rate of the high radiation region. Here we discuss the results of these tests and further studies using the FC-40.
** malvare4@fnal.gov
*** vnagasl@fnal.gov
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP044  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP045 Higher Multipoles in 3rd Integer Resonance Extraction 2437
 
  • V.P. Nagaslaev
    Fermilab, Batavia, Illinois, USA
  • K.A. Brown
    BNL, Upton, Long Island, New York, USA
  • M. Tomizawa
    KEK, Ibaraki, Japan
 
  The efficiency of slow extraction is becoming a limiting factor, as the demand for delivered beam power is constantly growing. New methods for improving extraction efficiency include folding the extraction separatrix using the higher multipoles. In this report we discuss a simple and effective approach to determine an optimal placement of those multipoles in the storage ring. This allows reduction of the beam losses and therefore, the level of prompt and residual radioactivity in the accelerator components and surrounding buildings by as much as 40% or more. We also explore here manipulating the higher order effects produced in the pure sextupole configurations for the same purpose and demonstrate that similar results can be achieved by only rearranging the sextupole magnets in the lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP045  
About • paper received ※ 10 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP048 Development of Spin Rotator and an Absolute Polarimeter for Polarized He-3 at BNL 2440
 
  • D. Raparia, G. Atoian, S. Ikeda, R.F. Lambiase, M. Okamura, A. Poblaguev, J. Ritter, S. Trabocchi, A. Zelenski
    BNL, Upton, Long Island, New York, USA
  • R. Milner, M. M. Musgrave
    MIT, Cambridge, Massachusetts, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
EBIS Preinjector will provide longitudinally polarized 3He++ ions with about 80% polarization and 5.1011 particles per bunch at 6 MeV, which must be rotated to vertical direction before it ions are injected into the Booster. The 3He++ longitudinal polarization is first rotated to the transverse direction by the 21.5° bending magnet. Then the solenoid spin-rotator rotates the spin to the vertical direction. The spin-rotator will be a pulsed solenoid with a reversible field to enable spin flips. The vertically polarized beam will be returned back to the straight HEBT line by the system of three dipole magnets after the spin rotator solenoid. The low-energy polarimeter can be installed in the straight beam line section after the second dipole magnet. To measure transverse (vertical) polarization of the 3He beam at 5-6 MeV, the spin correlated asymmetry of 3He scattering on a 4He gas target (~5 Torr) will be measured with left/right symmetric strip detectors. Paper will present status of the project.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP048  
About • paper received ※ 19 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS002 Study of a Proton Therapy Beamline for Eye Treatment with Beam Delivery Simulation (BDSIM) and an In-House Tracking Code 3088
 
  • E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse
    ULB - FSA - SMN, Bruxelles, Belgium
  • S.T. Boogert, L.J. Nevay, W. Shields
    JAI, Egham, Surrey, United Kingdom
 
  The complete modelling of passive scattering proton therapy systems is challenging and requires simulation tools that have capabilities in both beam transport and in the detailed description of particle-matter interactions. Beam Delivery Simulation (BDSIM) allows the seamless simulation of the transport of particles in a beamline and its surrounding environment. A complete 3D model can be built from Geant4, CLHEP and ROOT to provide a complete analysis of the primary beam tracking. This capability is applied to the eye treatment proton therapy machine part of the IBA Proteus Plus product line. Those simulations are compared with a fast in-house particle tracking code with a semi-analytical model of Multiple Coulomb Scattering. The preliminary results leading to the detailed knowledge of the beamline performance are discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS002  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THXXPLM2 Demonstration of Loss Reduction Using a Thin Bent Crystal to Shadow an Electrostatic Septum During Resonant Slow Extraction 3399
 
  • F.M. Velotti, P. Bestmann, M.E.J. Butcher, M. Calviani, M. Di Castro, M. Donzé, L.S. Esposito, M.A. Fraser, M. Garattini, S.S. Gilardoni, B. Goddard, V. Kain, J. Lendaro, A. Masi, D. Mirarchi, M. Pari, J. Prieto, S. Redaelli, R. Rossi, W. Scandale, R. Seidenbinder, P. Serrano Galvez, L.S. Stoel, C. Zamantzas, V. Zhovkovska
    CERN, Meyrin, Switzerland
  • F.M. Addesa, F. Iacoangeli
    INFN-Roma, Roma, Italy
  • A.G. Afonin, Y.A. Chesnokov, A.A. Durum, V.A. Maisheev, Yu.E. Sandomirskiy, A.A. Yanovich
    IHEP, Moscow Region, Russia
  • J.E. Borg, M. Garattini, G. Hall, T. James, M. Pesaresi
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • A.S. Denisov, Y. Gavrikov, Yu.M. Ivanov, M.A. Koznov, L.G. Malyarenko, V. Skorobogatov
    PNPI, Gatchina, Leningrad District, Russia
  • F. Galluccio
    INFN-Napoli, Napoli, Italy
  • F. Murtas
    INFN/LNF, Frascati, Italy
 
  A proof-of-principle experiment demonstrating the feasibility of using a thin, bent crystal aligned upstream of an extraction septum (ES) to increase the efficiency of the third-integer resonant slow extraction process has been carried out at the CERN Super Proton Synchrotron (SPS). With the primary aim of reducing the beam loss and induced radio-activation of the SPS, the crystal was aligned to both the beam and the septum to reduce by up to 40% the beam intensity impinging the ES and increase the intensity entering the external transfer line. In this contribution, we introduce the concept and the prototype system that was installed in 2018 before reporting in detail on the dedicated program of machine development studies carried out to characterise its performance and demonstrate operational feasibility. The performance reach and compatibility with other loss reduction techniques proposed to further increase the extraction efficiency, such as phase space folding with octupoles, is discussed in view of future high intensity operation.  
slides icon Slides THXXPLM2 [1.397 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THXXPLM2  
About • paper received ※ 15 May 2019       paper accepted ※ 28 May 2019       issue date ※ 21 June 2019  
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