Search

The Centre for the Clinical Application of Particles' Laser-hybrid Accelerator for Radiobiological Applications (LhARA) facility is being studied and requires simulation of novel accelerator components (such as the Gabor lens capture system), detector simulation and simulation of the ion beam interaction with cells. The first stage of LhARA will provide protons up to 15 MeV for in vitro studies. The second stage of LhARA will use a fixed-field accelerator to increase the energy of the particles to allow in vivo studies with protons and in vitro studies with heavier ions. BDSIM, a Geant4 based accelerator simulation tool, has been used to perform particle tracking simulations to verify the beam optics design done by BeamOptics and these show good agreement. Design parameters were defined based on an EPOCH simulation of the laser source and a series of mono-energetic input beams were generated from this by BDSIM. The tracking results show the large angular spread of the input beam (0.2 rad) can be transported with a transmission of almost 100% whilst keeping divergence at the end station very low (

The Muon Ionization Cooling Experiment (MICE) collaboration has developed the MICE Analysis User Software (MAUS) to simulate and analyze experimental data. It serves as the primary codebase for the experiment, providing for offline batch simulation and reconstruction as well as online data quality checks. The software provides both traditional particle-physics functionalities such as track reconstruction and particle identification, and accelerator physics functions, such as calculating transfer matrices and emittances. The code design is object orientated, but has a top-level structure based on the Map-Reduce model. This allows for parallelization to support live data reconstruction during data-taking operations. MAUS allows users to develop in either Python or C++ and provides APIs for both. Various software engineering practices from industry are also used to ensure correct and maintainable code, including style, unit and integration tests, continuous integration and load testing, code reviews, and distributed version control. The software framework and the simulation and reconstruction capabilities are described.

A Neutrino Factory (NF) could deliver precision measurements of the CP-violating phase, δ C P , to rival measurements in the quark sector. Current NF designs require muon beam cooling, which the Muon Ionisation Cooling Experiment (MICE) will demonstrate. A lower energy approach to the NF concept, using neutrinos from stored muons (nuSTORM), does not require muon cooling and can contribute significantly to neutrino physics, specifically in the area of cross-section measurements and sterile neutrino searches.

McCartney makes a valid point about the questionable effectiveness of the flu vaccine, but she provides little substantive evidence of the negative effects of vaccination.1 She quotes the 2016-17 effectiveness of 41% in adults under 65, which would have been sufficient to provide herd immunity in many recent influenza outbreaks …

Coherent Smith–Purcell (SP) radiation has already been applied as a technique to measure the longitudinal bunch profile of charged particle beams in the low to intermediate energy range. However, with the advent of the International Linear Collider and the need to develop a non-invasive method of measuring the bunch profile, it has become necessary to carry out experiments at the highest possible energies. The paper summarizes some recent work at intermediate (45 MeV) energy and presents the first observations of SP radiation from a 28.5 GeV beam at SLAC. The experimental challenges and future possibilities of coherent Smith–Purcell radiation as a longitudinal bunch profile diagnostic tool are also discussed.

During magnet commissioning in September 2015, the leads on coil M1 of the downstream spectrometer solenoid failed. The coil will not be operational for MICE Step IV. Revised optics settings for the Step IV data taking are reviewed.

The nuSTORM facility has been designed to deliver beams of electron neutrinos and muon neutrinos (and their anti-particles) from the decay of a stored muon beam with a central momentum of 3.8 GeV/c and a momentum acceptance of 10%. The facility is unique in that it will: 1. Allow searches for sterile neutrinos of exquisite sensitivity to be carried out; 2. Serve future long- and short-baseline neutrino-oscillation programs by providing definitive measurements of electron neutrino and muon neutrino scattering cross sections off nuclei with percent-level precision; and 3. Constitutes the crucial first step in the development of muon accelerators as a powerful new technique for particle physics. The document describes the facility in detail and demonstrates its physics capabilities. This document was submitted to the Fermilab Physics Advisory Committee in consideration for Stage I approval. The nuSTORM facility has been designed to deliver beams of electron neutrinos and muon neutrinos (and their anti-particles) from the decay of a stored muon beam with a central momentum of 3.8 GeV/c and a momentum acceptance of 10%. The facility is unique in that it will: 1. Allow searches for sterile neutrinos of exquisite sensitivity to be carried out; 2. Serve future long- and short-baseline neutrino-oscillation programs by providing definitive measurements of electron neutrino and muon neutrino scattering cross sections off nuclei with percent-level precision; and 3. Constitutes the crucial first step in the development of muon accelerators as a powerful new technique for particle physics. The document describes the facility in detail and demonstrates its physics capabilities. This document was submitted to the Fermilab Physics Advisory Committee in consideration for Stage I approval.

The idea of using a muon storage ring to produce a high-energy ({approx_equal} 50 GeV) neutrino beam for experiments was first discussed by Koshkarev in 1974. A detailed description of a muon storage ring for neutrino oscillation experiments was first produced by Neuffer in 1980. In his paper, Neuffer studied muon decay rings with E{sub {mu}} of 8, 4.5 and 1.5 GeV. With his 4.5 GeV ring design, he achieved a figure of merit of {approx_equal} 6 x 10{sup 9} useful neutrinos per 3 x 10{sup 13} protons on target. The facility we describe here ({nu}STORM) is essentially the same facility proposed in 1980 and would utilize a 3-4 GeV/c muon storage ring to study eV-scale oscillation physics and, in addition, could add significantly to our understanding of {nu}{sub e} and {nu}{sub {mu}} cross sections. In particular the facility can: (1) address the large {Delta}m{sup 2} oscillation regime and make a major contribution to the study of sterile neutrinos, (2) make precision {nu}{sub e} and {bar {nu}}{sub e} cross-section measurements, (3) provide a technology ({mu} decay ring) test demonstration and {mu} beam diagnostics test bed, and (4) provide a precisely understood {nu} beam for detector studies. The facility is the simplest implementation of the Neutrino Factory concept. In our case, 60 GeV/c protons are used to produce pions off a conventional solid target. The pions are collected with a focusing device (horn or lithium lens) and are then transported to, and injected into, a storage ring. The pions that decay in the first straight of the ring can yield a muon that is captured in the ring. The circulating muons then subsequently decay into electrons and neutrinos. We are starting with a storage ring design that is optimized for 3.8 GeV/c muon momentum. This momentum was selected to maximize the physics reach for both oscillation and the cross section physics. See Fig. 1 for a schematic of the facility.

Coherent Smith-Purcell (SP) radiation originating from three different gratings has been measured at End Station A, SLAC, and has been used to reconstruct the time profile of the electron bunches. The beam energy during these experiments was 28.5 GeV ($\ensuremath{\gamma}\ensuremath{\cong}55\text{ }773$) and the number of electrons in the bunch was $0.9--1.4\ifmmode\times\else\texttimes\fi{}{10}^{10}$. The spectral distribution of the radiated energy was measured by means of an array of 11 pyroelectric detectors. Typical values of the FWHM of the bunch length are about 2.5 ps, but sharper peaks with FWHM less than 2.0 ps have also been observed. The longitudinal profile also varies with accelerator conditions and can best be approximated by a superposition of 3--4 Gaussian curves. Some typical profiles are presented, together with a discussion of the limitations and strengths of coherent SP radiation as a diagnostic tool. It is concluded that SP radiation offers excellent prospects in this respect, not only in the picosecond range, but potentially in the femtosecond range as well.

We report some preliminary results of the Smith-Purcell radiation produced by the interaction of the 28.5 GeV electron beam with a ruled grating at the Stanford Linear Accelerator Center (SLAC). The objects of the experiment were to investigate the longitudinal (temporal) profile of the beam and to confirm that the radiated power was in agreement with the predictions of our surface current theory of the emission. The results are compared with those from earlier, lower, electron energy experiments and preliminary analysis indicates that our theoretical approach is valid over more than a four order range of electron energy from ~2 MeV to ~30 GeV.

We report on measurements of picosecond bunch lengths and the energy-z correlation of the bunch with a high energy electron test beam to the A-line and end station A (ESA) facilities at SLAC. The bunch length and the energy-Z correlation of the bunch are measured at the end of the linac using a synchrotron light monitor diagnostic at a high dispersion point in the A-line and a transverse RF deflecting cavity at the end of the linac. Measurements of the bunch length in ESA were made using high frequency diodes (up to 100 GHz) and pyroelectric detectors at a ceramic gap in the beamline. Modelling of the beam's longitudinal phase space through the linac and A-line to ESA is done using the 2-dimensional tracking program LiTrack, and LiTrack simulation results are compared with data. High frequency diode and pyroelectric detectors are planned to be used as part of a bunch length feedback system for the LCLS EEL at SLAC. The LCLS also plans precise bunch length and energy-Z correlation measurements using transverse RF deflecting cavities.

Four hitherto undescribed endodeoxyribonucleases, temporarily designated A(1), A(2), A(3), and B, have been isolated from E. coli K-12. Each requires Mg(++) and is not stimulated by ATP or S-adenosylmethionine. A(3) is strongly inhibited by Fe(+++) and weakly inhibited by ATP, S-adenosylmethionine, and DPN, whereas B is inhibited by caffeine. Each can be purified free of exonuclease or DNA-3'-phosphatase. A(1) (molecular weight approximately 72,000) cleaves single-stranded, circular fd DNA to form 3'-hydroxyl termini and introduces nicks and breaks in the closed, double-stranded replicative form DNA of fd (fd RFI). A(2) (molecular weight approximately 46,000) cleaves fd DNA and introduces nicks and breaks in RFI, forming 3'-hydroxyl- and 5'-phosphoryl termini. A(3) (molecular weight approximately 38,000) cleaves fd DNA to form 3'-hydroxyl termini and introduces only nicks in fd RFI. Irradiation of the RFI with ultraviolet light markedly increases the rate of hydrolysis by A(3). B appears to form 3'-phosphoryl termini with fd DNA, but its characterization is highly preliminary due to its instability.

Various workers in recent years have found that the Gouy-Chapman theory of the diffuse electrical double layer provides useful predictions of swelling behavior of certain 2:1 clays in dilute solutions. Calcium-saturated montmorillonite was apparently an exception. It swelled appreciably in dilute CaCl2 solutions, but much less than predicted by theory, and to an extent depending on previous compression history. Earlier swelling studies with calcium montmorillonite were repeated with similar (but not identical) results. In addition, specimens with various histories of compression were examined by X-ray diffraction methods. Every specimen showed [001] spacings of ., regardless of degree of compression or reswelling. Analysis of the . diffraction peaks by literal use of the Scherrer equation indicated that in uncompressed material (prepared by resin exchange from the sodium form) packets, or "tactoids" averaging about 4.5 montmorillonite particles each, produced the diffracted beam. The indicated number of particles increased irreversibly to about 8 as the maximum pressure experienced by a specimen increased to 100 atm. These results suggest that volume changes of compressed specimens were not associated with elastic bending of montmorillonite particles. Literal use of the Scherrer equation permits estimation of average spacing between tactoids from water content data. The slope of curves relating this spacing to pressure were surprisingly close to that predicted by application of double-layer equations, but large "dead volume" corrections must be applied if this is to be taken as evidence that swelling in calcium montmorillonite is in reasonable agreement with double-layer theory. It is concluded that the lowest energy state for calcium montmorillonite in dilute CaCI2 is represented by a single "crystal" with [001] spacing. Where attainment of this ordered state is prevented by imperfect orientation, swelling can occur, and is not incompatible with osmotic repulsion inherent in the diffuse doublelayer model. View complete article To view this complete article, insert Disc 2 then click button8

WARKENTIN et al. 1, following up earlier work of Schofield2, Bolt and Miller3, and others, showed that swelling pressures developed by suspensions of sodium montmorillonite on an ultra filter could be predicted satisfactorily from a diffuse ion layer model based on classical Gouy–Chapman theory. Warkentin et al. also reported results of preliminary experiments with calcium montmorillonite for which the same model appeared to be inappropriate. A significant result was the decrease in magnitude of reswelling observed as the peak pressure applied to the sample increased. They concluded that forces not taken into account in the calculation must be present. Recently, Aylmore and Quirk4, Greacen5 and others have published discussions of these results which may now require reconsideration in view of further studies of calcium montmorillonite swelling.