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neutron

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MO101 J-PARC Project kaon, linac, proton, hadron 1
 
  • S. Nagamiya
    KEK, Ibaraki
 
 

About ten years ago (2001) a new accelerator project to provide high-intensity proton beams proceeded into its construction phase. This project is called the J-PARC (Japan Proton Accelerator Research Complex), and it was completed about a year ago in 2009. The construction was performed under a cooperation of two institutions, KEK and JAEA. The goal of the accelerator power is 1 MW proton beams at 3 GeV, with 400 MeV Linac injector, and 0.75 MW beams at 50 GeV. Three experimental facilities are presently available: 1) the Materials and Life Experimental Facility where pulsed neutrons and muon beams from 3 GeV are produced and utilized, 2) the Hadron Experimental Facility where kaon beams are produced, with a slow extraction mode from the 50 GeV (currently, 30 GeV is used), and 3) the Neutrino Experimental Facility with fast extraction mode from the 50 GeV ring. I would like to review the current status of the accelerators and experimental facilities, in particular, under the emphasis of what are actually going on in regard experimental programs. I also would like to mention a future scope of the J-PARC.

 
MO103 SNS Operation at 1 MW and Beyond cavity, linac, target, ion 11
 
  • S. Henderson
    ORNL, Oak Ridge, Tennessee
 
 

This talk will present the stutus of SNS operation at 1MW and plan beyond it.

 
MOP034 Observation of Ozone Explosion of Liquid Nitrogen Induced by Irradiation with Electron Linear Accelerator electron, radiation, target, photon 130
 
  • R. Taniguchi, N. Ito, T. Kojima, S. Okuda
    Osaka Prefecture University, Sakai
 
 

A pulsed electron radiography system has been developed, which consisted of an electron linear accelerator, a scintillation screen and a high sensitivity image sensor. The system was capable for high speed strobo-imaging by the use of the pulse feature of the electron beam with the pulse width about a few micro-second. On the other hand, the characteristics of electron images were different from X-ray images and neutron images. Absorption behavior of energetic electrons in materials is Bragg-like rather than exponential. Therefore, a high contrast transparent image was obtained by modulating of energy of the electron beam. By the use of this system and utilizing these features, we observed successfully an ozone explosion phenomenon of liquid nitrogen induced by electron irradiation, which has been considered to be a serious problem in material irradiation experiments.

 
MOP055 A CW SRF Linac to Drive Subcritical Nuclear Reactors proton, linac, SRF, cavity 178
 
  • M. Popovic
    Fermilab, Batavia
  • C.M. Ankenbrandt, R.P. Johnson
    Muons, Inc, Batavia
 
 

In the last 20 years, superconducting RF (SRF) cavities have been developed to the point that a CW SRF linac is the best candidate driver for subcritical reactors. We discuss how one appropriately designed linac can be used for an accelerator-driven subcritical (ADS) nuclear power station to produce more than 5 GW electrical power in an inherently safe region below criticality. Such a station will generate no greenhouse gases, produce minimal nuclear waste and no byproducts that are useful to rogue nations or terrorists, incinerate waste from conventional nuclear reactors, and efficiently use abundant thorium fuel that does not need enrichment. We describe the Linac parameters that can enable this vision of an almost inexhaustible source of power and we discuss how the corresponding reactor technology can be matched to these parameters.

 
MOP088 Spallation Neutron Source LLRF Temperature Dependence and Solution LLRF, DTL, controls, klystron 259
 
  • M.T. Crofford, T.W. Hardek, S.W. Lee, M.F. Piller
    ORNL, Oak Ridge, Tennessee
  • J.A. Ball, T.L. Davidson
    ORNL RAD, Oak Ridge, Tennessee
 
 

The Spallation Neutron Source (SNS) has been operating since the first neutrons were produced on April 29, 2006. During the last several years the beam energy has been methodically ramped-up and outlying issues solved to improve system reliability. During the beam studies a temperature dependence has been discovered with the Low-Level RF systems. The effect is small but readily observable as increased beam losses. The temperature dependence has been studied both in the accelerator and in the laboratory and the sensitive components identified. A prototype solution that replaces the temperature dependent components of the Low-Level RF System has been designed and is in initial testing. Preliminary results of the laboratory tests have been encouraging. Accelerator tests are planned after installation during the December 2010 maintenance cycle.

 
MOP089 Spallation Neutron Source High-Power Protection Module Test Stand controls, LLRF, linac, cavity 262
 
  • S.W. Lee, J.A. Ball, T.L. Davidson, S.L. Jones
    ORNL RAD, Oak Ridge, Tennessee
  • M.T. Crofford, T.W. Hardek
    ORNL, Oak Ridge, Tennessee
 
 

The Spallation Neutron Source (SNS) High-Power Protection Module (HPM) provided interlocks and fast shutdown for the RF system to protect the accelerating structures and high power RF (HPRF) Distribution System. The HPM has required some functionality upgrades since the start of beam operations and an upgrade to the HPM test stand was required to support these added features. The HPM test stand currently verifies functionality, RF channel calibration, and measurement of the speed of shutdown to ensure the specifications are meet. The upgraded test stand was implemented in a single FPGA to allow for future growth and flexibility. Work is currently progressing on automation of the test stand to better perform the required module calibration schedule.

 
MOP097 Design of a High Energy Beam Stop for Spiral2 linac, target, vacuum, beam-losses 283
 
  • E. Schibler, J.-C. Ianigro
    IN2P3 IPNL, Villeurbanne
  • J. Morales, N. Redon
    UCBL, Villeurbanne
  • L. Perrot
    IPN, Orsay
 
 

The driver accelerator of the Spiral2 facility will deliver deuteron (40MeV) and proton (33MeV) beams with current up to 5mA and heavy ion (14.5MeV/n) beams up to 1mA. At the very end of the LINAC, the main Beam Stop will have to withstand a peak power of 200kW for deuterons, with an associated power density from 120W/mm2 to more than 700W/mm2. These challenging specifications impose the design of a new high efficiency Beam Stop that has been nicknamed SAFARI (French acronym of Optimized Beam Stop Device for High Intensity Beams). From the beam characteristics and activation constraints, we proposed and developed a complete design. We will present this original design and the different studies and optimizations which have been done: The Beam Stop shape marries to the beam characteristics in order to smooth for the best power density and improve thermo-mechanical behaviour under nominal and critical beams. Cooling system is directly machined from Beam Stop blocks. Optimization by various fluid studies and calculations led us to a new high efficiency counter-current water cooling system. We then compare calculated behaviour with first results obtained on our recent functional mock-up

 
MOP101 Rebuncher Cavities for the FRANZ Bunch Compressor cavity, impedance, linac, proton 295
 
  • D. Noll, L.P. Chau, M. Droba, O. Meusel, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main
 
 

The Frankfurt Neutron Source (FRANZ) currently under construction at IAP (Goethe University of Frankfurt) is designed to produce short neutron pulses at high intensity and repetition rates up to 250 kHz [*]. To achieve a bunch length of one nanosecond despite the high space charge forces, a bunch compressor of the Mobley type [**] using four dipole magnets and two rebunchers has been developed [***] to merge 9 linac bunches into the final focus. The first rebuncher cavity, a λ/4 resonator operating at 87.5 MHz, has to feature nine beam paths due to the multi-trajectory system. Additionally the gaps have to be displaced relatively to each other in a way that all bunches arrive at the correct rf phase. The second rebunching cavity will provide final focusing as well as an energy variation of ±0.2 MeV in front of the target and will be operating at 175 MHz. This paper presents the design of these novel cavities as well as the simulated beam dynamic properties.


* Meusel et al., LINAC 2006
** Mobley, Phys. Rev. 88(2), 360-361 (1951)
*** Chau et al, LINAC 2010

 
TU301 RFQ for CW Applications rfq, linac, vacuum, ion 372
 
  • A. Pisent
    INFN/LNL, Legnaro (PD)
 
 

CW RFQs requires solid design since they have to deal with design challenges and technological limitations. This talk overviews the recent performances of some of the most powerful RFQ cavities. Development, industrialisation and commissioning results of CW RFQ are describe and discussed, with recent update on two emblematic designs: IFMIF and TRASCO.

 
TUP022 A Linac for Compact Pulsed Hadron Source Project AT Tsinghua University Beijing proton, rfq, DTL, target 1
 
  • X. Guan
    TUB, Beijing
 
 

This paper will be generally reported that a new project of the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China. CPHS consists of a proton linac (13MeV, 16kW, Operating frequency 325MHz, peak current 50 mA, 0.5 ms pulse width at 50 Hz), a neutron target station (a Be target, moderators and reflector), and a small-angle neutron scattering instrument, a neutron imaging/radiology station, and a proton irradiation station. The linac accelerator is the main part of this project, which including a ECR ion source. LEBT section, a RFQ accelerator, a DTL linac and a HEBT An An experimental platform for further proton applications and more neutron beam lines will be added at a later stage. Currently, fabrication of the accelerator components has begun while the neutron target station, beam lines and instruments are under design study. The initial phase of the CPHS construction is scheduled to complete in the end of 2012.

 
TUP025 Operational Status and Life Extension Plans for the Los Alamos Neutron Science Center (LANSCE) proton, target, scattering, isotope-production 452
 
  • K.W. Jones, J.L. Erickson, R.W. Garnett, M.S. Gulley
    LANL, Los Alamos, New Mexico
 
 

The Los Alamos Neutron Science Center (LANSCE) accelerator and beam delivery complex generates the proton beams that serve three neutron production sources, a proton radiography facility and a medical and research isotope production facility. The recent operating history of the facility, including both achievements and challenges, will be reviewed. Plans for performance improvement will be discussed, together with the underlying drivers for the ongoing LANSCE Life Extension project. The details of this latter project will also be discussed.

 
TUP085 Beam Cross Section Monitor for INR Linac ion, linac, proton, vacuum 605
 
  • P.I. Reinhardt-Nickoulin, A. Feschenko, S.A. Gavrilov, I.V. Vasilyev
    RAS/INR, Moscow
 
 

The monitor to measure a transverse cross section of the accelerated beam has been developed and implemented in INR Linac. Operation of the monitor is based upon utilization of residual gas ionization. Ion flux cross section after extraction of the ions from the beam line by electrostatic field and subsequent energy separation in electrostatic analyzer reproduces a transverse cross section of the accelerator beam. Aμchannel plate intensifier followed by a phosphor screen is used to observe ion cross section. The image is optically transmitted to a CCD camera installed remotely and shielded for protection. The monitor enables to observe beam cross section, beam profiles and beam position, as well as their evolution in time within a wide range of beam intensities and energies. Monitor operation and parameters are described. Some experimental results are presented.

 
THP051 Retrospective on Fundamental Power Couplers for the Spallation Neutron Source at Oak Ridge cavity, vacuum, cryomodule, superconducting-cavity 866
 
  • M. Stirbet
    JLAB, Newport News, Virginia
 
 

As of September 2009 a sustainable 1 MW in beam power was achieved at Oak Ridge, continuing to make SNS the highest energy-pulsed neutron source available for scientific research worldwide. This paper evaluates the FPCs designed and built at JLAB for the SNS project, emphasizing their performance and related issues addressed during prototyping, qualification on the RF power test stand at room temperature, superconducting cavity commissioning and successful but challenging operation with beam for more than 5 years.


Mircea. Stirbet@jlab.org

 
THP113 Design of the 2.45 GHz ECR Proton Source and LEBT in CPHS (Compact Pulsed Hadron Source) proton, rfq, ion, plasma 1001
 
  • Z. Feng, X. Guan, J. Wei, H.Y. Zhang
    TUB, Beijing
  • Z.W. Liu, H.W. Zhao
    IMP, Lanzhou
 
 

Responding to the demand of accelerator front inject system of the Compact Pulsed Hadron Source (CPHS) in Tsinghua university in 2009, an electron cyclotron resonance (ECR) proton source (2.45 GHz, 1.5 KW) and a low-energy-beam-transport (LEBT) system are designed and manufacted. In this source, the H2 plasma is restricted by an axial magnetic field shaped by the source body produced by an all-permanent-magnet design (NdFeB rings). The 50-keV pulsed proton beam (50 Hz/0.5 ms) extracted by a four-electrode extraction system from the proton source passes through the LEBT system (1283 mm long), which is consist of two solenoid lens, two steering magnets and a cone configuration optically matches to the RFQ where the Twiss parameters α=1.354, β=7.731. The beam with 97% space charge neutralization rate has been simulated at 100 mA, 150 mm.mrad RFQ output current by Trace-3D and PBGUN. In this study, we describe the design of the proton source and LEBT technical systems along with intended operation.