Thomas J McManamy

SNS target tests at the LANSCE-WNR in 2001 – Part I☆

Testing of mercury filled targets in an 800 MeV proton beam was conducted at the Los Alamos Neutron Science Center-Weapons Neutron Research (LANSCE-WNR) facility on two occasions in 2001. The objective for the first test campaign was to investigate if target vessel cavitation damage could occur under transient pressure conditions much like the Spallation Neutron Source (SNS) target. Such an investigation was inspired after mechanical tests conducted by a Japan Atomic Energy Research Institute (JAERI/KEK) team revealed cavitation pitting in a mercury container having comparable pressure wave intensity. The first WNR test confirmed cavitation damage with 200 proton pulses on each of two test targets. As a result, concerns arose that the lifetime of the SNS target could be seriously limited. A second test campaign was then prepared and conducted to investigate if alternate target materials or geometries could reduce or eliminate the damage. Tested materials included Stellite, Nitronic-60 as well as 316LN stainless steel (the baseline SNS target material) that was cold worked and surface hardened. Theories that the original test target geometry caused the damage were checked with tests using thick beam windows and a target with a non-axisymmetric shape. This paper describes the test program and covers target preparation, irradiation conditions, post-test decontamination and an overview of the examinations performed. J.D. Hunn covers the detailed description of the metallurgical examinations in another paper here at IWSMT-5.

The Second Target Station at the ORNL Spallation Neutron Source

After the Spallation Neutron Source (SNS) construction project was completed in June, 2006, development of plans to construct a second target station (STS) at SNS began. These plans have evolved to the establishment of a reference concept for a STS and associated neutron beam instruments, and the evaluation of the expected performance for this station, all of which have been documented in a White Paper. Based on this White Paper, the Department of Energy has approved development of a detailed conceptual design leading to a construction project for the STS. The STS reference design is based on pulse stealing from the 60 Hz SNS accelerator system, with one pulse of every three going to the STS and the other two going to the first target station. The STS would operate in long-proton-pulse mode with no pulse compression in the accumulator ring, and would be optimized for production of intense beams of cold neutrons. The reference concept for the STS and the estimated performance for this concept will be discussed

Target Systems Overview for the Spallation Neutron Source

The purpose and requirements of target systems as well as the technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the Spallation Neutron Source, are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis, and planned hardware research and development program are also described.

Targets for high-intensity particle production

The high-powered target development efforts at ORNL for the Spallation Neutron Source and the muon collider/neutrino factory are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges.

Ultracold neutron turbine for the advanced neutron source

Abstract The paper describes a design for an ultracold neutron turbine source which has been developed for the planned Advanced Neutron Source at Oak Ridge. An “S”-shaped neutron guide transports very cold neutrons from a horizontal Cold Source to the turbine location. For the design neutron velocity of 40 m/s, this guide approaches the efficiency of a straight guide, while it filters strongly against neutrons with velocities above 60 m/s. The proposed turbine is designed for operation at a peripheral velocity of 20 m/s. This design speed, slower than that of existing turbines, has been chosen to minimize the effect of the circular turbine motion. The lower speed, coupled with the use of 58 Ni as the turbine blade material, allows a significant increase in performance with fewer blades.

The National Spallation Neutron Source target station: a general overview

The technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the National Spallation Neutron Source (NSNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis and the planned hardware research and development program are also described.

The Spallation Neutron Source Beam Commissioning and Initial Operations

The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

Development of High Powered Target Systems for the Spallation Neutron Source and the Muon Collider/Neutrino Factory

The purpose and requirements of the Spallation Neutron Source (SNS) and the target area of the Muon Collider/Neutrino Factory are presented. Parts of the technologies that are being utilized to design these facilities are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges.