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Broadband diffractive lens (open access)

Broadband diffractive lens

Significant progress has been made toward solving the century-old problem of chromatic aberrations in diffractive optics. Our approach exploits modern materials and microfabrication technology and is very different from the purely diffractive strategy,'' which is commonly employed and which results in multiple diffractive elements separated by a finite distance. We have developed a Fresnel zone plate lens comprised of a serial stack of patterned minus-filters which allows broadband radiation to be focused (or imaged) without longitudinal or transverse chromatic aberrations. 7 refs., 4 figs.
Date: May 28, 1991
Creator: Ceglio, N. M.; Hawryluk, A. M.; London, R. A.; Seppala, L. G. (Lawrence Livermore National Lab., CA (USA)) & Gaines, D. P. (Brigham Young Univ., Provo, UT (USA))
System: The UNT Digital Library
Thermal effects and mirror surface figure requirements for a diagnostic beamline at the Advanced Light Source (open access)

Thermal effects and mirror surface figure requirements for a diagnostic beamline at the Advanced Light Source

An imaging beamline based on a Kirkpatrick-Baez mirror configuration has been designed to image the electron beam in the ALS storage ring, to measure its size and shape. The electron beam emittance will be small ({epsilon}h = 3.4 {times} 10{sup {minus}9} m rad) and the quality of the image is extremely sensitive to surface figure distortion of the mirrors. Thermal distortions and surface temperatures have been calculated for radiatively cooled mirrors of various materials in a search for a simple design which avoids water cooling. The choice of mirror material and the thermal and mechanical design is discussed. 6 refs.
Date: October 28, 1991
Creator: Warwick, T. (Lawrence Berkeley Lab., CA (United States)) & Sharma, S. (Brookhaven National Lab., Upton, NY (United States))
System: The UNT Digital Library
Advanced Light Source beam position monitor (open access)

Advanced Light Source beam position monitor

The Advanced Light Source (ALS) is a synchrotron radiation facility nearing completion at LBL. As a third-generation machine, the ALS is designed to produce intense light from bend magnets, wigglers, and undulators (insertion devices). The facility will include a 50 MeV electron linear accelerator, a 1.5 GeV booster synchrotron, beam transport lines, a 1--2 GeV storage ring, insertion devices, and photon beam lines. Currently, the beam injection systems are being commissioned, and the storage ring is being installed. Electron beam position monitors (BPM) are installed throughout the accelerator and constitute the major part of accelerator beam diagnostics. The design of the BPM instruments is complete, and 50 units have been constructed for use in the injector systems. We are currently fabricating 100 additional instruments for the storage ring. In this paper I discuss engineering fabrication, testing and performance of the beam pickup electrodes and the BPM electronics.
Date: October 28, 1991
Creator: Hinkson, J.
System: The UNT Digital Library
Water cooled metal optics for the Advanced Light Source (open access)

Water cooled metal optics for the Advanced Light Source

The program for providing water cooled metal optics for the Advanced Light Source at Berkeley is reviewed with respect to fabrication and metrology of the surfaces. Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from prototype mirrors and grating blanks will be presented, which show exceptionally low microroughness and mid-period error. We will briefly describe out improved version of the Long Trace Profiler, and its importance to out metrology program. We have completely redesigned the mechanical, optical and computational parts of the profiler system with the cooperation of Peter Takacs of Brookhaven, Continental Optical, and Baker Manufacturing. Most important is that one of our profilers is in use at the vendor to allow testing during fabrication. Metrology from the first water cooled mirror for an ALS beamline is presented as an example. The preplating processing and grinding and polishing were done by Tucson Optical. We will show significantly better surface microroughness on electroless nickel, over large areas, than has been reported previously.
Date: October 28, 1991
Creator: McKinney, W.R.; Irick, S.C. (Lawrence Berkeley Lab., CA (United States)) & Lunt, D.L.J. (Tucson Optical Research Corp., AZ (United States))
System: The UNT Digital Library
Modeling the absorption of intense, short laser pulses in steep density gradients (open access)

Modeling the absorption of intense, short laser pulses in steep density gradients

A subroutine which calculates the absorption of short pulse electromagnetic radiation in a material has been installed into the laser fusion modeling program called LASNEX. Calculational results show the necessity for NLTE physics to account for ionization, the development of non-exponential density profiles for the expanding plasma and movement of the critical point toward the surface which results in Doppler shifts of the reflected light. Comparison of calculations of local scale lengths with experiments shows not only good agreement but the correct scaling with intensity. 8 refs., 5 figs.
Date: January 28, 1991
Creator: Alley, W.E.
System: The UNT Digital Library
Catalytic studies on a novel synthesis of methanol (open access)

Catalytic studies on a novel synthesis of methanol

Catalytic studies on a new method for methanol synthesis from CO and H{sub 2} in a slurry reactor are described. This reaction proceeds through the carbonylation of methanol to methyl formate in the liquid phase followed by hydrogenolysis of methyl formate to two molecules of methanol; the net result is the reaction of CO with H{sub 2} to give methanol. Moderate temperatures and pressures (100--160{degrees}C, 50--65 atm) are used. Reaction rates using mixed catalysts comprised of an alkali methoxide and Cu-chromite are presented. It seems likely that Cu-chromite maintains the activity of the alkali methoxide catalyst. A mixed catalyst comprised of potassium methoxide and Cu-chromite was found to be the most active under the reaction conditions used. Evidence is provided for an interaction between the alkali methoxide and Cu-chromite. 27 refs., 6 figs., 2 tabs.
Date: June 28, 1991
Creator: Palekar, V.M.; Tierney, J.W. & Wender, I.
System: The UNT Digital Library
Advanced Light Source Beam Position Monitor (open access)

Advanced Light Source Beam Position Monitor

The Advanced Light Source (ALS) is a synchrotron radiation facility nearing completion at LBL. As a third-generation machine, the ALS is designed to produce intense light from bend magnets, wigglers, and undulators (insertion devices). The facility will include a 50 MeV electron linear accelerator, a 1.5 GeV booster synchrotron, beam transport lines, a 1--2 GeV storage ring, insertion devices, and photon beam lines. Currently, the beam injection systems are being commissioned, and the storage ring is being installed. Electron beam position monitors (BPM) are installed throughout the accelerator and constitute the major part of accelerator beam diagnostics. The design of the BPM instruments is complete, and 50 units have been constructed for use in the injector systems. We are currently fabricating 100 additional instruments for the storage ring. In this paper I discuss engineering fabrication, testing and performance of the beam pickup electrodes and the BPM electronics.
Date: October 28, 1991
Creator: Hinkson, J.
System: The UNT Digital Library
Thermal effects and mirror surface figure requirements for a diagnostic beamline at the Advanced Light Source (open access)

Thermal effects and mirror surface figure requirements for a diagnostic beamline at the Advanced Light Source

An imaging beamline based on a Kirkpatrick-Baez mirror configuration has been designed to image the electron beam in the ALS storage ring, to measure its size and shape. The electron beam emittance will be small ({epsilon}h = 3.4 {times} 10{sup {minus}9} m rad) and the quality of the image is extremely sensitive to surface figure distortion of the mirrors. Thermal distortions and surface temperatures have been calculated for radiatively cooled mirrors of various materials in a search for a simple design which avoids water cooling. The choice of mirror material and the thermal and mechanical design is discussed. 6 refs.
Date: October 28, 1991
Creator: Warwick, T. & Sharma, S.
System: The UNT Digital Library
Water cooled metal optics for the Advanced Light Source (open access)

Water cooled metal optics for the Advanced Light Source

The program for providing water cooled metal optics for the Advanced Light Source at Berkeley is reviewed with respect to fabrication and metrology of the surfaces. Materials choices, surface figure and smoothness specifications, and metrology systems for measuring the plated metal surfaces are discussed. Results from prototype mirrors and grating blanks will be presented, which show exceptionally low microroughness and mid-period error. We will briefly describe out improved version of the Long Trace Profiler, and its importance to out metrology program. We have completely redesigned the mechanical, optical and computational parts of the profiler system with the cooperation of Peter Takacs of Brookhaven, Continental Optical, and Baker Manufacturing. Most important is that one of our profilers is in use at the vendor to allow testing during fabrication. Metrology from the first water cooled mirror for an ALS beamline is presented as an example. The preplating processing and grinding and polishing were done by Tucson Optical. We will show significantly better surface microroughness on electroless nickel, over large areas, than has been reported previously.
Date: October 28, 1991
Creator: McKinney, W. R.; Irick, S. C. & Lunt, D. L. J.
System: The UNT Digital Library
The new BNL polarized negative ion source (open access)

The new BNL polarized negative ion source

A new ground state source of negative hydrogen ions with polarized nuclei ({rvec H}{sup {minus}}) is being developed at BNL. Extensive developmental research has been aimed at improving each element of ({rvec H}{sup {minus}}) production: cold H{degrees} beam, spin selection and focusing magnets, and ionizer. These elements have recently been integrated into a source. A first test with the accommodator nozzle cooled only to liquid nitrogen temperatures resulted in 5 {mu}A of H{sup {minus}}. Tests at liquid helium temperatures are now beginning. 7 refs., 1 fig.
Date: August 28, 1991
Creator: Hershcovitch, A. I.; Alessi, J. G.; DeVito, B. & Kponou, A. E.
System: The UNT Digital Library