THE RF SYSTEM DESIGN FOR THE SPALLATION NEUTRON SOURCE.

THE RF SYSTEM DESIGN FOR THE SPALLATION NEUTRON SOURCE. PDF Author:
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Languages : en
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Spallation Neutron Source (SNS) accelerator includes a nominally 1000 MeV, 2 mA average current linac consisting of a radio frequency quadrapole (RFQ), drift tube linac (DTL), coupled cavity linac (CCL), a medium and high beta super conducting (SC) linac, and two buncher cavities for beam transport to the ring. Los Alamos is responsible for the RF systems for all sections of the linac. The SNS linac is a pulsed proton linac and the RF system must support a 1 msec beam pulse at up to a 60 Hz repetition rate. The RFQ and DTL utilize seven, 2.5 MW klystrons and operate at 402.5 MHz. The CCL, SC, and buncher cavities operate at 805 MHz. Six, 5 MW klystrons are utilized for the CCL and buncher cavities while eighty-one 550 kW klystrons are used for the SC cavities. All of the RF hardware for the SNS linac is currently in production. This paper will present details of the RF system-level design as well as specific details of the SNS RF equipment. The design parameters will be discussed. One of the design challenges has been achieving a reasonable cost with the very large number of high-power klystrons. The approaches we used to reduce cost and the resulting design compromises will be discussed.

THE RF SYSTEM DESIGN FOR THE SPALLATION NEUTRON SOURCE.

THE RF SYSTEM DESIGN FOR THE SPALLATION NEUTRON SOURCE. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Spallation Neutron Source (SNS) accelerator includes a nominally 1000 MeV, 2 mA average current linac consisting of a radio frequency quadrapole (RFQ), drift tube linac (DTL), coupled cavity linac (CCL), a medium and high beta super conducting (SC) linac, and two buncher cavities for beam transport to the ring. Los Alamos is responsible for the RF systems for all sections of the linac. The SNS linac is a pulsed proton linac and the RF system must support a 1 msec beam pulse at up to a 60 Hz repetition rate. The RFQ and DTL utilize seven, 2.5 MW klystrons and operate at 402.5 MHz. The CCL, SC, and buncher cavities operate at 805 MHz. Six, 5 MW klystrons are utilized for the CCL and buncher cavities while eighty-one 550 kW klystrons are used for the SC cavities. All of the RF hardware for the SNS linac is currently in production. This paper will present details of the RF system-level design as well as specific details of the SNS RF equipment. The design parameters will be discussed. One of the design challenges has been achieving a reasonable cost with the very large number of high-power klystrons. The approaches we used to reduce cost and the resulting design compromises will be discussed.

The SNS Linac High Power RF System Design, Status, and Results

The SNS Linac High Power RF System Design, Status, and Results PDF Author:
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Category :
Languages : en
Pages : 3

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The Spallation Neutron Source being built at the Oak Ridge National Lab in Tennessee requires a 1 GeV proton linac. Los Alamos has responsibility for the RF systems for the entire linac. The linac requires 3 distinct types of RF systems: 2.5-MW peak, 402.5 MHz, RF systems for the RFQ and DTL (7 systems total); 5-MW peak, 805 MHz systems for the CCL and the two energy corrector cavities (6 systems total); and 550-kW peak, 805 MHz systems for the superconducting sections (8 1 systems total). The design of the SNS Linac RF system was presented at the 2001 Particle Accelerator Conference in Chicago. Vendors have been selected for the klystrons (3 different vendors), circulators (I vendor), transmitter (1 vendor), and high power RF loads (3 different vendors). This paper presents the results and status of vendor procurements, test results of the major components of the Linac RF system and our installation progress.

The RF System for the National Spallation Neutron Source Linac

The RF System for the National Spallation Neutron Source Linac PDF Author:
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Category :
Languages : en
Pages : 4

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The National Spallation Neutron Source (NSNS) system has been proposed to dramatically improve the neutron capabilities for science applications in the US. The NSNS is a fast pulse neutron source that would consist of a 1000 MeV H-linac, an accumulator ring, a neutron target, and an experimental area. Although the NSNS is to be built at Oak Ridge, the design responsibility is delegated to five US national laboratories, and the Los Alamos National Laboratory is responsible for the linac portion of this machine, from the output of the radio frequency quadrupole (RFQ) accelerator, to the entrance to the accumulator ring. In the baseline design, a total of 59 klystrons are used to provide the RF power for a 1-MW average power beam in the accumulator ring, and a 1.04 ms pulse length, 6.24% duty factor beam in the linac. The frequencies chosen are 402.5 MHz for the RFQ and drift tube linac (DTL) portions of the machine, and 805 MHz for the coupled-cavity DTL (CCDTL) and coupled cavity (CCL) portions of the linac. The baseline 805 MHz klystron is capable of 2.5 MW peak power into a flat load, and it contains a modulating anode. The backup 805 MHz klystron is cathode pulsed, and has a 5 MW peak output power. The modulators for these two klystrons are vastly different. The challenges and compromises for the two klystrons and their associated modulators and RF systems are discussed. The baseline design RF system is presented in detail.

Spallation Neutron Source High-power Rf Transmitter Design for High Availablility, Ease of Installation and Cost Containment

Spallation Neutron Source High-power Rf Transmitter Design for High Availablility, Ease of Installation and Cost Containment PDF Author:
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Category :
Languages : en
Pages : 3

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The availability goals and installation schedule for the Spallation Neutron Source (SNS) have driven the availability and installation of the SNS linac's high-power RF systems. This paper discusses how the high-power RF systems' availability and installation goals have been addressed in the RF transmitter design and procurement. Design features that allow R1; component failures to be quickly diagnosed and repaired are also presented. Special attention has been given lo interlocks, PLC fault logging and real-time interfaces to thc accelerator's Experimental Physics and Industrial Control System (EPICS) archive system. The availability and cost motivations for the use of different RF transmitter designs in the normalconducting and super-conducting sections of the linac are reviewed. Factory iicceptance tests used to insure fully functional equipment and thereby reduce the time spent on installation and cotnmissioning of the RF transmitters are discussed. Transmitter installation experience and klystron conditioning experience is used to show how these design features have helped and will continue to help the SNS linac to meet its availability and schedule goals.

STATUS OF THE OAK RIDGE SPALLATION NEUTRON SOURCE (SNS) RF SYSTEMS *

STATUS OF THE OAK RIDGE SPALLATION NEUTRON SOURCE (SNS) RF SYSTEMS * PDF Author:
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Category :
Languages : en
Pages :

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The SNS has been delivering production neutrons for five years with first beam delivered to the neutron target at the end of April 2006. On September 18, 2009 SNS officially reached 1 megawatt of beam on target marking the achievement of a decades-old dream of providing a U.S. megawatt class pulsed spallation source. The SNS is now routinely delivering 1 megawatt of beam power to the neutron target at over 85 percent of the scheduled beam time. The present effort is aimed at increasing availability eventually to 95 percent and gradually increasing the intensity to the 1.4 megawatt design level. While the RF systems have performed well since initial installation some improvements have been implemented. This paper provides a review of the SNS RF Systems, an overview of the performance of the various components and a detailed review of RF related issues addressed over the past several years.

Spallation Neutron Source

Spallation Neutron Source PDF Author:
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Category :
Languages : en
Pages : 21

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The rf system for the synchrotrons of the spallation neutron source is designed to accelerate 1.4 x 1014 protons/pulse to an energy of 3.6 GeV. Injection energy is 600 MeV. The synchrotron repetition frequency is 30 Hz, with a 50% duty factor. The choice of operating frequency is somewhat arbitrary. The authors propose a low frequency of 1.3 to 1.6 MHz, which is the second harmonic of the revolution frequency. The advantages of such a low frequency system are: (1) There will be two bunches in the machines and the time between bunches will be sufficiently long to allow for the rise time of the extraction kicker. No missing bunches will be necessary, which simplifies injection, and transient beam loading problems are avoided. (2) With only two bunches there are no unstable coupled-bunch modes of longitudinal instability. (3) In multi-gap low frequency cavities the transient time factor is essentially unity because the rf wavelength is much longer than the cavity dimensions. (4) Cavities in this low frequency range are basically lumped-element type structures, where the sources of the inductance and capacitance are clearly identified. This allows effective control of higher order mode impedances in such cavities. (5) Ferrite-loaded low-frequency cavities are necessarily low impedance structures; ferrites are lossy. This low impedance makes it possible to achieve system stability without large amounts of feedback in a heavily beam loaded system. (6) BNL has a good deal of experience in building rf systems in this range of frequency, voltage, and power level. This report outlines the essential parameters of a practical rf system for the synchrotrons of the Spallation Neutron Source. The design uses materials, ferrites and vacuum tubes, that are commercially available and with which the laboratory has recent experience.

Modeling and Design of a Low-level RF Control System for the Accumulator Ring at Spallation Neutron Source

Modeling and Design of a Low-level RF Control System for the Accumulator Ring at Spallation Neutron Source PDF Author: Michael G. Trout
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Category :
Languages : en
Pages : 134

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Since its commissioning in 2006, Spallation Neutron Source (SNS) at Oak Ridge National Laboratory has greatly contributed to the field of neutron science, but some critical systems are reaching end-of-life. This obsolescence must be addressed for the accelerator to continue providing world-class research capabilities. One such system needing redesign is the low-level RF (LLRF) control system for the proton accumulator ring. While this system has performed acceptably for over a decade, it is sparsely documented and robust operational models are unavailable. To ensure the new design meets or exceeds current performance metrics, we analyzed the existing LLRF control system and designed a system-accurate controller model. This model included a state-space representation of the RF accelerator cavity dynamics. Both the controller and cavity models are combined to provide complete, functional simulation capabilities for the SNS accumulator ring LLRF control system. We then realized the modeled controller in an FPGA using VHDL cores which were subsequently used to successfully regulate the accumulator ring. The designed controller was functional at repetition rates up to 160 Hz while system specifications only require 60 Hz operation. The designed controller achieved 1 MW beam-on-target operation at 60 Hz repetition rate and a fundamental frequency of approximately 1 MHz.

DESIGN OF THE SNS NORMAL CONDUCTING LINAC RF CONTROL SYSTEM.

DESIGN OF THE SNS NORMAL CONDUCTING LINAC RF CONTROL SYSTEM. PDF Author:
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Category :
Languages : en
Pages : 6

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The Spallation Neutron Source (SNS) is in the process of being, designed for operation in 2004. The SNS is a 1 GeV machine consisting of both a normal-conducting and super-conducting linac as well as a ring and target area The linac front end is a 402.5 MHz RFQ being developed by Lawrence Berkeley Lab. The DTL, being developed at Los Alamos National Laboratory, is also a copper structure operating at 402.5 MHz, with an 805 MHz CCL structure downstream of it. The expected output energy of the DTL is 87 MeV and that of the CCL is 185 MeV. The RF control system under development for the linac is based on the Low Energy Demonstration Accelerator's (LEDA) control system with some new features. This paper will discuss the new design approach and its benefits. Block diagrams and circuit specifics will be addressed. The normal conducting RF control system will be described in detail with reference to the super-conducting control system when appropriate.

Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 782

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Construction and Operation of the Spallation Neutron Source (TN, NY, IL, NM)

Construction and Operation of the Spallation Neutron Source (TN, NY, IL, NM) PDF Author:
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ISBN:
Category :
Languages : en
Pages : 726

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