The SNS control system communication network will take advantage of new, commercially available network switch features to increase reliability and reduce cost. A standard structured cable system will be installed. The decreasing cost of network switches will enable SNS to push the edge switches out near the networked devices and to run high-speed fiber communications all the way to the edge switches. Virtual Local Area Network VLAN) technology will be used to group network devices into logical subnets while minimizing the number of switches required. Commercially available single-board computers with TCP/IP interfaces will be used to provide terminal service plus remote power reboot service.
The fast extraction kicker system is one of the most important accelerator components, whose inner structure will be the main source of the impedance in the RCS. It is necessary to understand the kicker impedance before its installation into the tunnel. The conventional and improved wire methods are employed for the benchmarking impedance measurement results. The simulation and measurements confirm that the window-frame ferrite geometry and the end plate are the important structures causing the coupling impedance. The total impedance of the eight modules systems is determined by the scaling la…
In the rapid cycling synchrotron of the China Spallation Neutron Source, the anti-correlated painting was adopted for the design scheme of the injection system. In the beam commissioning, with the optimization of the anti-correlated painting,the injection beam loss has been well controlled and the injection efficiency has exceeded 99%. Combined with other aspects of adjustments, the beam power on the target has reached 50 kW smoothly. In this paper, we have studied the injection optimization in the beam commissioning. Compared to the simulation results of the design scheme, the transverse beam…
A coasting hadron beam with an elliptical transverse profile, uniform charge density, and small transverse four-dimensional (4D) emittance could improve accelerator performance in several contexts. A phase space painting method to generate such a distribution is being tested in the Spallation Neutron Source (SNS) accumulator ring. A critical component of these efforts is to measure the 4D emittance of the beam during accumulation. The 4D emittance can be reconstructed from measured beam profiles in two ways: in the multi-optics method, the optics between a reconstruction and measurement locati…
As a part of the ongoing XIIth plan project titled "R&D activities for high energy proton linac based spallation neutron source", the work on physics design of various subsystems of the injector linac and accumulator ring has been taken up at RRCAT, Indore. For the 1 GeV H- injector linac, physics design studies of individual systems have been completed, and the end to end beam dynamics simulation studies have been performed to ensure that the stringent beam dynamics criteria are satisfied for the optimized lattice. Physics design studies to optimize the linear lattice of the accumulator ring …
We describe the Fundamental Neutron Physics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.
We discuss the possibility to build a neutron target for nuclear reaction studies in inverse kinematics utilizing a storage ring and radioactive ion beams. The proposed neutron target is a specially designed spallation target surrounded by a large moderator of heavy water (D$_2$O). We present the resulting neutron spectra and their properties as a target. We discuss possible realizations at different experimental facilities.
We report on our efforts to optimize the geometry of neutron moderators and converters for the TRIUMF UltraCold Advanced Neutron (TUCAN) source using MCNP simulations. It will use an existing spallation neutron source driven by a 19.3 kW proton beam delivered by TRIUMF's 520 MeV cyclotron. Spallation neutrons will be moderated in heavy water at room temperature and in liquid deuterium at 20 K, and then superthermally converted to ultracold neutrons in superfluid, isotopically purified $^4$He. The helium will be cooled by a $^3$He fridge through a $^3$He-$^4$He heat exchanger. The optimization …
The power of the proton beam of a high-power spallation neutron source generally ranges from 100 kW to several MW. The distribution of the power density of the beam on the target is critical for the stable operation of the high-power spallation target. This study proposes a beam monitoring method that involves restoring the image of a high-power proton beam spot on a target based on the principle of pinhole imaging by using the back-streaming of secondary neutrons from the spallation target. Fast and indirect imaging of the beam spot can be achieved at a distance of tens of meters from the tar…
Progress on the 140 KV, 10 Megawatt Peak, 1 Megawatt Average Polyphase Quasi-Resonant Bridge, Boost Converter/Modulator for the Spallation Neutron Source (SNS) Klystron Power System
The reliability of the mercury spallation target is mission-critical for the neutron science program of the spallation neutron source at the Oak Ridge National Laboratory. We present an inverse uncertainty quantification (UQ) study using the Bayesian framework for the mercury equation of state model parameters, with the assistance of polynomial chaos expansion surrogate models. By leveraging high-fidelity structural mechanics simulations and real measured strain data, the inverse UQ results reveal a maximum-a-posteriori estimate, mean, and standard deviation of $6.5\times 10^4$ ($6.49\times 10…
A fast-switching, high-repetition-rate magnet and power supply have been developed for and operated at TRIUMF, to deliver a proton beam to the new ultracold neutron (UCN) facility. The facility possesses unique operational requirements: a time-averaged beam current of 40~$μ$A with the ability to switch the beam on or off for several minutes. These requirements are in conflict with the typical operation mode of the TRIUMF cyclotron which delivers nearly continuous beam to multiple users. To enable the creation of the UCN facility, a beam-sharing arrangement with another facility was made. The b…
A proposed Very Cold Neutron Source (VCNS) would operate with 4 ms long pulses at 5 Hz and 1 GeV. The energy per pulse would be 300 kJ, much higher than the Spallation Neutron Source (33 kJ/pulse) or the present IPNS (0.3 kJ/pulse), and the peak power on target would be 75 MW. This paper discusses ideas for the VCNS target and examines the possibility of conducting target tests at an 8-GeV proton linear accelerator which is being studied for construction at Fermilab.
European Spallation Source will be the brightest neutron source in the world. It is being built in Lund, Sweden. Over 120 superconducting cavities will be installed in the facility, each regulated by an individual LLRF control system. To reduce the risk associated with testing the systems on real cavities a Cavity Simulator was designed. It reproduces the behaviour of superconducting cavities used in the medium and high beta sections of ESS's Linac. The high power RF amplifier and piezo actuators parameters are also simulated. Based on the RF drive and piezo control signals the Cavity Simulato…
A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper
This conceptual design report provides a detailed account of the European Spallation Source neutrino Super Beam (ESS$ν$SB) feasibility study. This facility has been proposed after the measurements reported in 2012 of a relatively large value of the neutrino mixing angle $θ_{13}$, which raised the possibility of observing potential CP violation in the leptonic sector with conventional neutrino beams. The measured value of $θ_{13}$ also privileges the $2^{nd}$ oscillation maximum for the discovery of CP violation instead of the more typically studied $1^{st}$ maximum. The sensitivity at this $2^…
The mercury constitutive model predicting the strain and stress in the target vessel plays a central role in improving the lifetime prediction and future target designs of the mercury targets at the Spallation Neutron Source (SNS). We leverage the experiment strain data collected over multiple years to improve the mercury constitutive model through a combination of large-scale simulations of the target behavior and the use of machine learning tools for parameter estimation. We present two interdisciplinary approaches for surrogate-based model calibration of expensive simulations using evolutio…
