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An intensity interferometer for soft x-rays (open access)

An intensity interferometer for soft x-rays

We designed and built an intensity interferometer to characterize the spatial coherence of a soft x-ray undulator beam. The beam source size and shape can be determined from the measured coherence function. The instrument is 400 mm long and is mounted on a standard 204-mm diameter flange. This compact design is readily adaptable to other beamlines with sources of sufficient spectral brightness. Details of the interferometer design and performance are presented. We anticipate that when this technique is mature, it will provide a useful diagnostic for high brightness x-ray beams.
Date: July 15, 1994
Creator: Yang, L.; McNulty, I. & Gluskin, E.
System: The UNT Digital Library
Performance of a high resolution, high flux density SGM undulator beamline at the ALS (open access)

Performance of a high resolution, high flux density SGM undulator beamline at the ALS

The performance of ALS beamline 7.0 is described. This is an integrated system for delivering radiation from a 5cm period undulator to spectroscopy and microscopy experiments across the range of photon energies from 60eV to 1200eV. The beamline is engineered to deliver the highest possible flux, with negligible deformation of the optic surfaces due to heating. Two experiment stations are served with rapid interchangeability. We report on the measured operational parameters, the resolution and flux delivered, and the refocus of the light into a small spot at the experiment.
Date: July 15, 1994
Creator: Warwick, T.; Heimann, P.; Mossessian, D.; McKinney, W. & Padmore, H.
System: The UNT Digital Library
Experimental characterization of ALS undulator radiation (open access)

Experimental characterization of ALS undulator radiation

The radiation from the 5 cm period undulator at the Advanced Light Source (ALS) has been characterized using a transmission grating spectrometer. Spectral and angular distributions of radiation were measured for deflection parameter K values between 0.45 and 2.12 at low storage ring current (0.1--0.5 mA). From the calibration of the spectrometer, the absolute flux density of the undulator harmonics has been determined together with the spectral linewidth. The electron the beam emittance was determined by analyzing the angular distribution of the red-shifted fundamental. Comparison has been made with radiation calculations based upon the measured magnetic field data of the undulator. Including field errors, electron beam emittance and energy spread, good agreement is found between theoretically and experimentally determined harmonic widths and peak brightness.
Date: July 15, 1994
Creator: Heimann, P.; Mossessian, D.; Warwick, A.; Gullikson, E.; Wang, C.; Marks, S. et al.
System: The UNT Digital Library
Performance of photon position monitors and stability of undulator beams at the Advanced Light Source (open access)

Performance of photon position monitors and stability of undulator beams at the Advanced Light Source

Position monitors are implemented in three undulator beamlines at the ALS. Their performance has been studied carefully on one of these lines and is reviewed. The monitors work as expected and show the ALS to be an exceptionally stable source of synchrotron radiation.
Date: July 15, 1994
Creator: Warwick, T.; Andresen, N.; Portmann, G. & Jackson, A.
System: The UNT Digital Library
Two portable parallel tridiagonal solvers (open access)

Two portable parallel tridiagonal solvers

Many scientific computer codes involve linear systems of equations which are coupled only between nearest neighbors in a single dimension. The most common situation can be formulated as a tridiagonal matrix relating source terms and unknowns. This system of equations is commonly solved using simple forward and back substitution. The usual algorithm is spectacularly ill suited for parallel processing with distributed data, since information must be sequentially communicated across all domains. Two new tridiagonal algorithms have been implemented in FORTRAN 77. The two algorithms differ only in the form of the unknown which is to be found. The first and simplest algorithm solves for a scalar quantity evaluated at each point along the single dimension being considered. The second algorithm solves for a vector quantity evaluated at each point. The solution method is related to other recently published approaches, such as that of Bondeli. An alternative parallel tridiagonal solver, used as part of an Alternating Direction Implicit (ADI) scheme, has recently been developed at LLNL by Lambert. For a discussion of useful parallel tridiagonal solvers, see the work of Mattor, et al. Previous work appears to be concerned only with scalar unknowns. This paper presents a new technique which treats …
Date: July 15, 1994
Creator: Eltgroth, P. G.
System: The UNT Digital Library
Phase transformations and phase relations in Ti{sub 50}Pd{sub (50-x)}TM{sub x} alloys (open access)

Phase transformations and phase relations in Ti{sub 50}Pd{sub (50-x)}TM{sub x} alloys

The effect of transition metal (TM) substitution for Pd in Ti{sub 5O}Pd{sub (50-x}TM{sub x} alloys with x between 5 and 37.5 at.% and TM = V, Cr, Mn and Fe are being characterized by transmission electron microscopy and First-Principles Alloy Theory modeling. The goal is to obtain detailed structural information related to the ternary phase relations and transformations that are necessary for effective shape-memory alloy development. Thus far, the authors have found that the tend to have pseudobinary eutectoid-like configurations with a terminal TiPd and a non-close-packed long period ordered structure type crystal structure) based on the stoichiometry Ti{sub 2}PdTM. The systems exhibit a conventional martensitic transformation, as well as a new type of displacive transformation that shear-modulates B2 to produce a periodically distorted, but non-close-packed metastable product phase.
Date: July 15, 1994
Creator: Schwartz, A. J.; Sluiter, M. H.; Harmon, B. N. & Tanner, L. E.
System: The UNT Digital Library
A hybrid vehicle evaluation code and its application to vehicle design (open access)

A hybrid vehicle evaluation code and its application to vehicle design

This report describes a hybrid vehicle simulation model, which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates interactively, with all the vehicle information stored in data files. The code calculates fuel economy for three driving schedules, time for 0-96 km/h at maximum acceleration, hill climbing performance, power train dimensions, and pollution generation rates. This report also documents the application of the code to a hybrid vehicle that operates with a hydrogen internal combustion engine. The simulation model is used for parametric studies of the vehicle. The results show the fuel economy of the vehicle as a function of vehicle mass, aerodynamic drag, engine-generator efficiency, flywheel efficiency, and flywheel energy and power capacities.
Date: July 15, 1994
Creator: Aceves, S. M. & Smith, J. R.
System: The UNT Digital Library
Determination of halogens in a petroleum product by ion chromatography (open access)

Determination of halogens in a petroleum product by ion chromatography

A rapid, high-performance ion chromatography (HPIC) method with isocratic separation and the anion self-regenerating suppressor (in the chemical suppression mode, specifically for the determination of fluoride, chloride, bromide, and iodide in a petroleum product) is discussed. This is a proposed new method for a production laboratory within the Analytical Services Organization at the Oak Ridge Y-12 Plant.
Date: July 15, 1994
Creator: Tucker, H.L.
System: The UNT Digital Library