Bulletin of the American Physical Society
APS April Meeting 2014
Volume 59, Number 5
Saturday–Tuesday, April 5–8, 2014; Savannah, Georgia
Session S14: Topics in Accelerators and Beams |
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Sponsoring Units: DPB DPF Chair: Robert Bernstein, Fermi National Accelerator Laboratory Room: 102 |
Monday, April 7, 2014 1:30PM - 1:42PM |
S14.00001: High field muon ionization cooling channel for micron scale emittance Hisham Sayed, Robert Palmer A muon collider with center of mass energy of 1.5 TeV can achieve luminosity of 10$^{34}$ cm$^{-2}$ sec$^{-1}$ provided that the muon beam normalized transverse emittance be of the order of 25 microns. We present a complete final ionization cooling channel that can achieve such low transverse emittance requirements. The cooling is performed using liquid Hydrogen absorbers embedded in 40 T solenoids. A full simulation of the channel will be discussed including the re-accelerating and matching between stages. Additional studies of the space charge effects and absorber heating will be also covered. [Preview Abstract] |
Monday, April 7, 2014 1:42PM - 1:54PM |
S14.00002: A complete six-dimensional beam cooling scheme for a Muon Collider Diktys Stratakis, Scott Berg, Robert Palmer A high luminosity muon collider requires a significant reduction of the six-dimensional emittance prior acceleration. Obtaining the desired emittances requires transporting the muon beam through long section of a bean channel containing rf cavities, absorbers, and focusing solenoids. Here we propose new scheme to improve the performance of the channel, consequently increasing the number of transmitted muons and the lattice cooling efficiency. The key idea of our scheme is to tune progressively the main lattice parameters, such as the cell dimensions, rf frequency, and coil strengths, while always keeping the beam emittance significantly above the equilibrium value. We the aid of this novel approach we present for the first time a complete cooling scheme for a Muon Collider, and demonstrate a notable 6D emittance decrease by five order of magnitude. We review key parameters such as the required fields, frequencies and gradients for a complete muon cooling scenario. [Preview Abstract] |
Monday, April 7, 2014 1:54PM - 2:06PM |
S14.00003: Construction and Physics program for MICE next step IV Ben Freemire The International Muon Ionisation Cooling Experiment is progressing towards full demonstration of the feasibility of this cooling technology decisive for neutrino physics and muon colliders. Its next step IV should provide the first precise measurements of emittances and first evidence of cooling. Spectrometer solenoids, muon trackers and absober-FC (focus coil) modules are being assembled to make this possible in 2015. The physics programme of ionization cooling Step IV measurements will be described in detail, with Li-H and a few other promising absorber materials of different shapes. So will the progress of the hardware. The longer term final step V and step VI complete demonstration measurements being simultaneously prepared (re-acceerating RFCC modules, RF cavities inside their own focusing CC (``coupling'' coils) will also be outlined. [Preview Abstract] |
Monday, April 7, 2014 2:06PM - 2:18PM |
S14.00004: Non-Scaling FFAG lattice for the eRHIC Dejan Trbojevic, Steven Brooks, Francois Meot, Scott Berg, Wuzheng Meng, Nicholaos Tsoupas, Brett Parker, Vadim Ptistyn, Peter Thieberger, Vladimir Litvinienko, Thomas Roser, Michiko Minty The future electron ion collider eRHIC the ``QCD test facility'' will continue extraordinary results of the present Relativistic Heavy Ion Collider RHIC. There will be collisions between polarized electrons with heavy ions and with polarized protons/He$^{3}$ using existing superconducting RHIC accelerator and with electrons accelerated inside of the existing tunnel. Electron acceleration will be with the Electron Recovery Linac (ERL) with a combination with Non-Scaling Fixed Field Alternating Gradient arcs. Two NS-FFAG allow electrons to pass through the same structure with an energy range between 1.334 and 21.1 GeV. After collisions the beam is brought back by the NS-FFAG's and decelerated to the initial energy and directed to the dump. [Preview Abstract] |
Monday, April 7, 2014 2:18PM - 2:30PM |
S14.00005: Radiation Heating Analysis for Superconducting Undulator Laura Boon, Katherine Harkay, Yury Ivanyushenkov, Yuko Shiroyanagi In January 2013 the Advanced Photon Source commissioned a Superconducting Undulator (SCU). The superconducting magnet is thermally isolated from the beam vacuum chamber, which absorbs the beam-induced heating [Y. Ivanyushenkov et al, IEEE T. Appl. Supercon. 22 (3) (2012) ~DOI: 10.1088/1742-6596/425/3/032007]. The cryo-coolers cooling the vacuum chamber can handle 40 W of heating. Throughout the SCU design process calculations were made to determine the radiation heating from an on-axis and off-axis electron beam. Simulation results show that when the electron beam is vertically off-axis radiation heating increases from the on-axis heating of less than 1 W. During user operation beam-position-limiting detectors (BPLD) are used to limit beam motion and keep the radiation heating below 25 W. During machine studies when the BPLD is not armed other measures must be taken to protect the SCU. Presented in this talk will be the comparison between analytical calculations and measured temperature rise on the installed SCU. The measured temperatures have been converted to a power using a finite element model. [Preview Abstract] |
Monday, April 7, 2014 2:30PM - 2:42PM |
S14.00006: Beam Position Monitoring in the CSU Accelerator Facility Joshua Einstein, Max VanKeuren, Stephen Watras A Beam Position Monitoring (BPM) system is an integral part of an accelerator beamline, and modern accelerators can take advantage of newer technologies and designs when creating a BPM system. The Colorado State University (CSU) Accelerator Facility will include four stripline detectors mounted around the beamline, a low-noise analog front-end, and digitization and interface circuitry. The design will support a sampling rate greater than 10 Hz and sub-100 $\mu$m accuracy. [Preview Abstract] |
Monday, April 7, 2014 2:42PM - 2:54PM |
S14.00007: High Repetition Rate Crab Cavity Prototype for an Electron-Ion Collider Alejandro Castilla, Jean Delayen A 750 MHz superconducting rf dipole cavity has been studied as part of the crab crossing correction system for a large crossing angle (50 mrad) and high current electron-ion collider (0.5/3 A per bunch). The crab cavity prototype for Jefferson Lab's Medium Energy Electron-Ion Collider (MEIC) has been built at Niowave, Inc. In this talk we will present the principal rf properties of the design such as a broad separation of the Higher Order Modes (HOM) with respect to the operating (fundamental) mode, high quality factor, balanced surface electric and magnetic fields and low multipacting barriers, along with the results and experimental analysis of the cavity performance at 4 K and 2 K during tests realized at the Jefferson Lab facilities. [Preview Abstract] |
Monday, April 7, 2014 2:54PM - 3:06PM |
S14.00008: Superconducting Spoke Cavities for High-Velocity Applications Christopher Hopper, Jean Delayen Low frequency, compact half-wave cavities, including spoke cavities, are typically designed for the low energy section of particle accelerators. The advantages these structures offer can also prove beneficial for the high-velocity section of accelerators designed for certain applications. In this talk, the basic electromagnetic design considerations and proposed applications will be presented. [Preview Abstract] |
Monday, April 7, 2014 3:06PM - 3:18PM |
S14.00009: Design of a New Acceleration System for High-Current Pulsed Proton Beams from an ECR Source Andrew L. Cooper, Ivan Pogrebnyak, Jason T. Surbrook, Keegan J. Kelly, Bret P. Carlin, Arthur E. Champagne, Thomas B. Clegg A primary objective for accelerators at TUNL's Laboratory for Experimental Nuclear Astrophysics (LENA) is to maximize target beam intensity to ensure a high rate of nuclear events during each experiment. Average proton target currents of several mA are needed from LENA's electron cyclotron resonance (ECR) ion source because nuclear cross sections decrease substantially at energies of interest \textless 200 keV. We seek to suppress undesired continuous environmental background by pulsing the beam and detecting events only during beam pulses. To improve beam intensity and transport, we installed a more powerful, stable microwave system for the ECR plasma, and will install a new acceleration system. This system will: reduce defocusing effects of the beam's internal space charge; provide better vacuum with a high gas conductance accelerating column; suppress bremsstrahlung X-rays produced when backstreaming electrons strike internal acceleration tube structures; and provide better heat dissipation by using deionized water to provide the current drain needed to establish the accelerating tube's voltage gradient. Details of beam optical modeling calculations, proposed accelerating tube design, and initial beam pulsing tests will be described. [Preview Abstract] |
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