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in creator/contributor: "DiGennaro, R."

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Multilayer mirrors as power filters in insertion device beamlines

The power-filtering capabilities of multilayer band-pass x-ray mirrors relative to total reflection low-pass mirrors is presented. Results are based on calculations assuming proposed wiggler sources on the upcoming generation of low energy (1.5 GeV) and high energy (7.0 GeV) synchrotron radiation sources. Results show that multilayers out-perform total reflection mirrors in terms of reduction in reflected power by roughly an order of magnitude, with relatively small increases in total absorbed … more

Date: August 1, 1988

Creator: Kortright, J. B. & DiGennaro, R. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A directly cooled grating substrate for ALS (Advanced Light Source) undulator beam lines

Design analyses using finite element methods are presented for thermal distortion of water-cooled diffraction grating substrates for a potential application at the LBL Advanced Light Source, demonstrating that refinements in cooling channel configuration and heat flux distribution can significantly reduce optical surface distortion with high heat loads. Using an existing grating substrate design, sensitivity of tangential slope errors due to thermal distortion is evaluated for a variety of ther… more

Date: August 1, 1989

Creator: DiGennaro, R. & Swain, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A water-cooled mirror system for synchrotron radiation

This paper describes the design and performance of a directly-cooled soft x-ray mirror system which has been developed at Lawrence Berkeley Laboratory for synchrotron radiation beam lines in which mirror thermal distortion must be minimized for acceptable optical performance. Two similar mirror systems are being built: the first mirror has been installed and operated at the National Synchrotron Light Source on the X-17T mini-undulator beam line and will be moved to the permanent X-1 beam line w… more

Date: June 1, 1987

Creator: DiGennaro, R.; Gee, B.; Guigli, J.; Hogrefe, H.; Howells, M. & Rarback, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The SNS RFQ Commissioning

LBNL has built for the Spallation Neutron Source (SNS) project a 402.5 MHz RFQ that is designed to accelerate up to 60 mA H{sup -} from 65 keV to 2.5 MeV [1]. A one millisecond pulse length at 60 Hz provides a 6% duty factor. The RFQ has now been built, conditioned at full duty factor and tested with beam. This paper will present results from the final installation, tuning and beam commissioning. Beam measurements include acceleration and transport efficiencies and transverse emittances. The LE… more

Date: August 16, 2002

Creator: Ratti, A.; Ayers, J.; Doolittle, L.; DiGennaro, R.; Gough, R.A.; Hoff, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ion-source and LEBT issues with the front-end systems for the Spallation Neutron Source

The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project are being built by Berkeley Lab and will deliver a pulsed 40-mA H{sup -} ion beam at 2.5 MeV energy to the subsequent Drift-Tube Linac. The FES accelerator components comprise an rf driven, volume-production, cesium-enhanced, multi-cusp Ion Source; an electrostatic Low-Energy Beam Transport (LEBT) that includes provisions for transverse focusing, steering, and beam chopping; an RFQ accelerator; and a Medium-Energy Beam T… more

Date: September 1, 2001

Creator: Keller, R.; Cheng, D.; DiGennaro, R.; Gough, R. A.; Greer, J.; Leung, K. N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The LBL 55-meter spherical grating monochromator at SSRL (Stanford Synchrotron Radiation Laboratory)

The Lawrence Berkeley Laboratory 55-m spherical grating monochromator (SGM) beamline is located as a branch line of the 54-pole wiggler/undulator at the Stanford Synchrotron Radiation Laboratory (SSRL). It was designed and constructed by LBL's Center for X-Ray Optics and the engineering staff of LBL's Advanced Light Source with the cooperation and assistance of the research group of David Shirley at LBL and the staff of SSRL. The main goals of the project were to test the SGM concept and to dev… more

Date: August 1, 1989

Creator: McKinney, W.R.; Howells, M.R.; Lauritzen, T.; Chin, J.; DiGennaro, R.; Fong, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Progress with the SNS front-end systems

The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project have been described in detail elsewhere [1]. They comprise an rf-driven H{sup {minus}} ion source, electrostatic LEBT, four-vane RFQ, and an elaborate MEBT. These systems are planned to be delivered to the SNS facility in Oak Ridge in June 2002. This paper discusses the latest design features, the status of development work, component fabrication and procurements, and experimental results with the first commissioned beam… more

Date: May 1, 2001

Creator: Keller, R.; Abraham, W.; Ayers, J. J.; Cheng, D. W.; Cull, P.; DiGennaro, R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Soft x-ray imaging with 35 period undulator at the NSLS

Prior to the Phase II shutdown at the National Synchrotron Light Source (NSLS) in March 1987, a 10-period mini-undulator was used for soft x-ray imaging on the temporary X-17T beamline for six months. During this brief period we gained considerable experience in the use of undulator radiation for high brightness applications, including the use of high power optics, and position feedback. We commissioned a new scanning microscope using high resolution zone plates, and a fast laser interferometer… more

Date: January 1, 1988

Creator: Buckley, C.; Rarback, H.; Alforque, R.; Shu, D.; Ade, H.; Hellman, S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Weak Lensing from Space I: Instrumentation and Survey Strategy

A wide field space-based imaging telescope is necessary to fully exploit the technique of observing dark matter via weak gravitational lensing. This first paper in a three part series outlines the survey strategies and relevant instrumental parameters for such a mission. As a concrete example of hardware design, we consider the proposed Supernova/Acceleration Probe (SNAP). Using SNAP engineering models, we quantify the major contributions to this telescope's Point Spread Function (PSF). These P… more

Date: April 23, 2003

Creator: Rhodes, Jason; Refregier, Alexandre; Massey, Richard; Albert, Justin; Bacon, David; Bernstein, Gary et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

SNAP Near Infrared Detectors

The SuperNova/Acceleration Probe (SNAP) will measure precisely the cosmological expansion history over both the acceleration and deceleration epochs and thereby constrain the nature of the dark energy that dominates our universe today. The SNAP focal plane contains equal areas of optical CCDs and NIR sensors and an integral field spectrograph. Having over 150 million pixels and a field-of-view of 0.34 square degrees, the SNAP NIR system will be the largest yet constructed. With sensitivity in t… more

Date: July 29, 2002

Creator: Tarle, G.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

SNAP Satellite Focal Plane Development

The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to a… more

Date: July 7, 2003

Creator: Bebek, C.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Baltay, C. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

SNAP Telescope

The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applic… more

Date: July 29, 2002

Creator: Lampton, Michael L.; Akerlof, C. W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

SNAP Focal Plane

The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square-degree field sensitive in the visible and near-infrared wavelength regime. We describe the requirements for the instrument suite and the evolution of the focal plane design to the present concept in which all the instrumentation--visible and near-infrared imagers, spectrograph, and star guiders--share one common focal plane.

Date: July 29, 2002

Creator: Lampton, Michael L.; Kim, A.; Akerlof, C. W.; Aldering, G.; Amanullah, R.; Astier, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department