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Commissioning of the advanced light source dual-axis streak camera

Description: A dual-axis camera, Hamamatsu model C5680, has been installed on the Advanced Light Source photon-diagnostics beam-line to investigate electron-beam parameters. During its commissioning process, the camera has been used to measure single-bunch length vs. current, relative bunch charge in adjacent RF buckets, and bunchphase stability. In this paper the authors describe the visible-light branch of the diagnostics beam-line, the streak-camera installation, and the timing electronics. They will show graphical results of beam measurements taken during a variety of accelerator conditions.
Date: May 1997
Creator: Hinkson, J.; Keller, R. & Byrd, J.
Partner: UNT Libraries Government Documents Department

Modeling of X-ray beamlines and devices

Description: X-ray beamlines on synchrotron sources are similar in size and complexity to beamlines at state-of-the-art neutron sources. The design principles, tools, and optimization strategies for synchrotron beamlines are also similar to those of neutron beamlines. The authors describe existing design tools for modeling synchrotron radiation beamlines and describe how these tools have evolved over the last two decades. The development of increasingly powerful modeling tools has been driven by the escalating cost and sophistication of state-of-the-art beamlines and by a world-wide race to exploit advanced synchrotron radiation sources.
Date: December 31, 1996
Creator: Ice, G.E.
Partner: UNT Libraries Government Documents Department

Advanced Light Source activity report 1996/97

Description: Ten years ago, the Advanced Light Source (ALS) existed as a set of drawings, calculations, and ideas. Four years ago, it stored an electron beam for the first time. Today, the ALS has moved from those ideas and beginnings to a robust, third-generation synchrotron user facility, with eighteen beam lines in use, many more in planning or construction phases, and hundreds of users from around the world. Progress from concepts to realities is continuous as the scientific program, already strong in many diverse areas, moves in new directions to meet the needs of researchers into the next century. ALS staff members who develop and maintain the infrastructure for this research are similarly unwilling to rest on their laurels. As a result, the quality of the photon beams the authors deliver, as well as the support they provide to users, continues to improve. The ALS Activity Report is designed to share the results of these efforts in an accessible form for a broad audience. The Scientific Program section, while not comprehensive, shares the breadth, variety, and interest of recent research at the ALS. (The Compendium of User Abstracts and Technical Reports provides a more comprehensive and more technical view.) The Facility Report highlights progress in operations, ongoing accelerator research and development, and beamline instrumentation efforts. Although these Activity Report sections are separate, in practice the achievements of staff and users at the ALS are inseparable. User-staff collaboration is essential as they strive to meet the needs of the user community and to continue the ALS's success as a premier research facility.
Date: September 1997
Partner: UNT Libraries Government Documents Department

Radial Moment Calculations of Coupled Electron-Photon Beams

Description: The authors consider the steady-state transport of normally incident pencil beams of radiation in slabs of material. A method has been developed for determining the exact radial moments of 3-D beams of radiation as a function of depth into the slab, by solving systems of 1-D transport equations. They implement these radial moment equations in the ONEBFP discrete ordinates code and simulate energy-dependent, coupled electron-photon beams using CEPXS-generated cross sections. Modified P{sub N} synthetic acceleration is employed to speed up the iterative convergence of the 1-D charged particle calculations. For high-energy photon beams, a hybrid Monte Carlo/discrete ordinates method is examined. They demonstrate the efficiency of the calculations and make comparisons with 3-D Monte Carlo calculations. Thus, by solving 1-D transport equations, they obtain realistic multidimensional information concerning the broadening of electron-photon beams. This information is relevant to fields such as industrial radiography, medical imaging, radiation oncology, particle accelerators, and lasers.
Date: July 19, 2000
Creator: Franke, Brian C. & Larsen, Edward W.
Partner: UNT Libraries Government Documents Department

A microwave beam waveguide undulator for a brilliant above 100 keV photon source.

Description: For generation of photons above 100-keV with a magnetic field strength in the range 0.2-0.5 Tesla, an undulator wavelength {lambda}{sub u} shorter than 5 mm may be needed with beam in the Advanced Photon Source (APS) storage ring. A microwave beam waveguide undulator system has been investigated for generation of such light. The waveguide structure consists of two parallel reflector surfaces that can be derived from an elliptically cylindrical waveguide. The structure can support deflecting TE{sub m0} modes with very low microwave loss. A microwave ring resonator circuit employing the beam waveguide is considered to construct an undulator with the above requirement. Microwave properties of the beam waveguide structure have been investigated, and the design criteria for a microwave undulator are discussed.
Date: April 19, 1999
Creator: Kang, Y. W.
Partner: UNT Libraries Government Documents Department

Improving measurement quality assurance for photon irradiations at Department of Energy facilities. Final technical report

Description: For radiation-instrument calibration to be generally acceptable throughout the US, direct or indirect traceability to a primary standard is required. In most instances, one of the primary standards established at NIST is employed for this purpose. The Department of Energy Laboratory Accreditation Program (DOELAP) is an example of a program employing dosimetry based on the NIST primary photon-, beta particle- and neutron-dosimetry standards. The NIST primary dosimetry standards for bremsstrahlung were first established in the 1950s. They have been updated since then on several occasions. In the 1970s, Technical Committee 85 of the International Standards Organization (ISO) started its work on establishing sets of internationally acceptable, well-characterized photon beams for the calibration of radiation-protection instruments. It is the intent of this paper to make a detailed comparison between the current NIST and the most up-to-date ISO techniques. At present, 41 bremsstrahlung techniques are specified in ISO 4037 while NIST supports a total of 32 techniques. Given the existing equivalences, it makes sense to try to extend the NIST techniques to cover more of the ISO Narrow Spectrum and High Air-Kerma Rate Series. These extensions will also allow the possibility for use of ISO beam techniques in future revisions of the DOELAP standard, which has been suggested by DOE. To this end, NIST was funded by DOE to procure material and make adaptations to the existing NIST x-ray calibration ranges to allow NIST to have the capability of producing all the ISO bremsstrahlung techniques. The following sections describe the steps that were taken to achieve this.
Date: May 1, 1996
Partner: UNT Libraries Government Documents Department

The calibration and characterization of a research x-ray unit

Description: The proper characterization of an X-ray unit is necessary for the utilization of the source as a dosimetry calibration standard. Upon calibration, the X-ray unit can be used for X-ray calibrations of survey, diagnostic, and reference-class, instruments and for X-ray irradiations of personnel dosimeters. It was the goal of this research to provide the Radiation Calibration Laboratory at Oak Ridge National Laboratory with a characterized research X-ray unit that could be used in reference dosimetry. The energy spectra were characterized by performing half value layer measurements and by performing a spectral analysis. Two spectral reconstruction techniques were investigated and compared. One involved using a previously determined detector response matrix and a backstripping technique. The other reconstruction technique was developed for this research using neural computing. A neural network was designed and trained to reconstruct measured X-ray spectra from data collected with a high- purity germanium spectroscopy system. Five X-ray beams were successfully characterized and found to replicate the ANSI N13.11 and the National Institute of Standards Technology X-ray beam codes. As a result, these prepared X-ray beams have been used for reference dosimetry. It has been shown that a neural network can be used as a spectral reconstruction technique, which contributes less error to the lower energy portion of the spectrum than other techniques.
Date: June 1, 1996
Creator: Johnson, C.M.
Partner: UNT Libraries Government Documents Department


Description: Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is ...
Date: May 1, 1999
Creator: FOERSTER,C.
Partner: UNT Libraries Government Documents Department

High resolution soft x-ray bending magnet beamline 9.3.2 with circularly polarized radiation capability at the Advanced Light Source

Description: Bending magnet beamline 9.3.2 at the Advanced Light Source (ALS) was designed for high resolution spectroscopy in the soft x-ray energy region, covering a range from 30 eV to 1500 eV with three gratings. The monochromator itself is a standard fixed included angle 55 m spherical grating monochromator and was originally used at the Stanford Synchrotron Radiation Laboratory (SSRL) as a prototype for later insertion device based monochromators for the ALS. For operations at the ALS, the toroidal pre-mirror used at SSRL to vertically focus onto the entrance slit and horizontally focus onto the exit slit was replaced by two separate crossed mirrors (Kirkpatrick-Baez configuration). Circularly polarized radiation is obtained by inserting a water-cooled movable aperture in front of the vertically focusing mirror to allow selecting the beam either above or below the horizontal plane. To maintain a stable beam intensity through the entrance slit, the photocurrent signals from the upper and lower jaws of the entrance slit are utilized to set a feedback loop with the vertically deflecting mirror Piezoelectric drive. The beamline end station has a rotatable platform (through 60{degree}) that accommodates two experimental chambers, enabling the synchrotron radiation to be directed to either one without breaking vacuum.
Date: August 1, 1995
Creator: Hussain, Z.; Heimann, P.A.; McKinney, W.; Padmore, H.A.; Huff, W.R.A.; Kellar, S.A. et al.
Partner: UNT Libraries Government Documents Department


Description: Geological specimens are often complex materials that require different analytical methods for their characterization. The parameters of interest may include the chemical composition of major, minor and trace elements. The chemical compounds incorporated in the minerals, the crystal structure and isotopic composition need to be considered. Specimens may be highly heterogeneous thus necessitating analytical methods capable of measurements on small sample volumes with high spatial resolution and sensitivity. Much essential information on geological materials can be obtained by using ion or photon beams. In this chapter we describe the principal analytical techniques based on particle accelerators, showing some applications that are hardly possible with conventional methods. In particular, the following techniques will be discussed: (1) Synchrotron radiation (SR) induced X-ray emission (SRIXE) and particle-induced X-ray emission (PEE) and other ion beam techniques for trace element analysis. (2) Accelerator mass spectrometry (AMS) for ultra sensitive analysis of stable nuclides and long-lived radionuclides. In most of the cases also the possibilities of elemental and isotopic analysis with high resolution will be discussed.
Date: November 1998
Creator: Torok, Sz. B.; Jones, K. W. & Tuniz, C.
Partner: UNT Libraries Government Documents Department

Initial diagnostics commissioning results for the Advanced Photon Source (APS)

Description: Principal diagnostics systems have been installed and nearly all have been commissioned on the subsystems of the Advanced Photon Source (APS) facility. Data have been obtained on beam position, beam profile, current, beam loss rate, and synchrotron radiation monitors on both injector rings and most recently the main 7-GeV storage ring. Results for the 150- to 450-MeV electron beams in the accumulator ring, up to 7 GeV in the injector synchrotron, and 4.5 to 7 GeV in the SR will be presented.
Date: July 1, 1995
Creator: Lumpkin, A.; Patterson, D. & Wang, X.
Partner: UNT Libraries Government Documents Department

Initial tests of the dual-sweep streak camera system planned for APS particle-beam diagnostics

Description: Initial tests of a dual-sweep streak system planned for use on the Advanced Photon Source (APS) have been performed using assets of the Argonne Wakefield Accelerator (AWA) facility. The short light pulses from the photoelectric injector drive laser in both the visible ({lambda}=496 nm, {Delta}t{approximately}1.5 ps (FWHM)), and the ultraviolet ({lambda}=248 nm, {Delta}t{approximately}5 ps (FWHM)) were used. Both a UV-visible S20 photocathode streak tube and a UV-to-x-ray Au photocathode streak tube were tested. Calibration data with an etalon were also obtained. A sample of dual-sweep streak data using optical synchrotron radiation on the APS injector synchrotron is also presented.
Date: July 1, 1995
Creator: Lumpkin, A.; Yang, B.; Gai, W. & Cieslik, W.
Partner: UNT Libraries Government Documents Department

An Accelerator Control Middle Layer Using MATLAB

Description: Matlab is an interpretive programming language originally developed for convenient use with the LINPACK and EISPACK libraries. Matlab is appealing for accelerator physics because it is matrix-oriented, provides an active workspace for system variables, powerful graphics capabilities, built-in math libraries, and platform independence. A number of accelerator software toolboxes have been written in Matlab -- the Accelerator Toolbox (AT) for model-based machine simulations, LOCO for on-line model calibration, and Matlab Channel Access (MCA) to connect with EPICS. The function of the MATLAB ''MiddleLayer'' is to provide a scripting language for machine simulations and on-line control, including non-EPICS based control systems. The MiddleLayer has simplified and streamlined development of high-level applications including configuration control, energy ramp, orbit correction, photon beam steering, ID compensation, beam-based alignment, tune correction and response matrix measurement. The database-driven Middle Layer software is largely machine-independent and easy to port. Six accelerators presently use the software package with more scheduled to come on line soon.
Date: May 15, 2005
Creator: Portmann, Gregory J.; Corbett, Jeff & Terebilo, Andrei
Partner: UNT Libraries Government Documents Department

Three-body Forces in Photoreactions on 3He

Description: We have measured the three-body photobreakup of {sup 3}He with the tagged photon beam and the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility, in the photon energy range between 0.35 GeV and 1.55 GeV. This measurement constitutes a wide-ranging survey of two- and three-body processes in the gamma{sup 3}He {yields} ppn reaction channel, thanks to the high statistics and large kinematic coverage obtained with the CLAS. Total and partially integrated differential cross sections for the full ppn data set and for selected kinematics were extracted and are compared to theoretical predictions of Laget (up to 1.0 GeV). At low photon energies, the calculations are generally in fair agreement with the data. The comparison shows evidence of strong contributions of three-body absorption mechanisms, especially in the star kinematics, a symmetric configuration of the three final-state nucleons. Mostly the effects of two-body absorption mechanisms are se en, as expected, in the pp-pair-breakup kinematics, where the neutron does not participate in the reaction. The quasi-two-body breakup shows angular distributions consistent with preliminary gamma{sup 3}He --> pd results, extracted from our experiment. The ratio of cross sections for the star configuration and for the two-body kinematics, shows a maximum for three-body effects at a photon energy of about 0.5 GeV, corresponding to a reduced photon wavelength of 0.4 fm. The 4pi-integrated cross section is in excellent agreement with previous experimental results from DAPHNE up to 800 MeV; no previous results have been obtained above this energy.
Date: February 1, 2003
Creator: Niccolai, Silvia
Partner: UNT Libraries Government Documents Department

Thermo-mechanical optimization of photon shutter 1 for APS front ends

Description: Photon shutter 1 (PS1) is one of the most critical elements on the front end of the beamlines at the Advanced Photon Source (APS) now under construction at Argonne National Laboratory (ANL). The PS1 uses an enhanced heat transfer tube developed at ANL. Due to large thermal loads on these components, inclined geometry is used in the design to spread the footprint of the x-ray beam. Even then, thermal loads are very critical. To address the thermal and thermo-mechanical issues, analytical studies have been applied to a simplified model of the shutter tube. The maximum temperature and maximum effective stress have been parametrically studied. Results for maximum temperatures and stresses are obtained and compared with the available strength/fatigue data for the materials proposed for the shutter design.
Date: July 28, 1992
Creator: Nian, H.L.T.; Kuzay, T.M. & Sheng, I.C.A.
Partner: UNT Libraries Government Documents Department

Introduction to the measurement of noise with application to particle accelerator beam stabilization.

Description: One of the most important figures of merit for a synchrotron radiation source, once specified beam intensity and energy have been achieved, is charged particle beam stability. While a significant effort has been expended at the Advanced Photon Source (APS) to reduce or eliminate undesirable sources of beam motion, it will be necessary to employ active feedback to stabilize the user photon beams to the very stringent levels required. This becomes especially important when one considers that transverse beam stability is generally quoted as a fraction of beam dimensions. Since source brightness tends to be inversely proportional to these transverse dimensions, it should be evident that x-ray beamline users in general will support any and all efforts to reduce the transverse charged particle beam dimensions. The obvious corollary to this is that coincident with emittance reduction efforts must come improvements in our ability to both measure and correct the particle beam trajectory. Presently, there are at least two active proposals at the APS for reducing both horizontal and vertical emittance. A simple change in lattice functions gives a factor of two reduction in horizontal and vertical beam emittance, while a machine studies program focusing on the correction of horizontal-vertical coupling will allow a reduction of vertical emittance by a factor of 100 or more. The Advanced Photon Source presently operates with the design natural emittance of 8.2 nm-rad, and without coupling correction, the vertical emittance is approximately 3% of this value. The APS design value for coupling is 10%. Given the design lattice functions, the effect of horizontal-vertical coupling on insertion device source beam size is shown in Table 1. Presently, the most stringent requirement on rf beam position monitors (RFBPMs) is derivable from the vertical orbit stability specification, namely, that the vertical charged particle beam trajectory must be stable ...
Date: December 21, 1998
Creator: Decker, G.
Partner: UNT Libraries Government Documents Department

Demonstration of electronic pattern switching and 10x pattern demagnification in a maskless micro-ion beam reduction lithography system

Description: A proof-of-principle ion projection lithography (IPL) system called Maskless Micro-ion beam Reduction Lithography (MMRL) has been developed and tested at the Lawrence Berkeley National Laboratory (LBNL) for future integrated circuits (ICs) manufacturing and thin film media patterning [1]. This MMRL system is aimed at completely eliminating the first stage of the conventional IPL system [2] that contains the complicated beam optics design in front of the stencil mask and the mask itself. It consists of a multicusp RF plasma generator, a multi-beamlet pattern generator, and an all-electrostatic ion optical column. Results from ion beam exposures on PMMA and Shipley UVII-HS resists using 75 keV H+ are presented in this paper. Proof-of-principle electronic pattern switching together with 10x reduction ion optics (using a pattern generator made of nine 50-{micro}m switchable apertures) has been performed and is reported in this paper. In addition, the fabrication of a micro-fabricated pattern generator [3] on an SOI membrane is also presented.
Date: May 31, 2002
Creator: Ngo, V.V.; Akker, B.; Leung, K.N.; Noh, I.; Scott, K.L. & Wilde, S.
Partner: UNT Libraries Government Documents Department

Vacuum ring exit chamber temperatures due to wiggler beam heating

Description: A study was made to determine the effects of a shift in the electron orbital plane and resulting displacement of the wiggler photon beam striking the inner surface of the existing vacuum chamber outer wall. The wiggler beam/vacuum chamber geometry is shown. 7 figures.
Date: January 1, 1984
Creator: Sharma, S. & Ulc, S.
Partner: UNT Libraries Government Documents Department

Practical applications of coherent transition radiation

Description: The predictable nature of transition radiation (TR) emissions has been demonstrated under a wide variety of experimental conditions. The reliable character of TR allows the design of specific practical applications that use emissions from the optical to the x-ray spectral regions. Applications often can be enhanced by the spatial coherence of TR, and some have become highly developed. New applications may be developed through the use of other related radiation mechanisms. 20 refs., 3 figs.
Date: October 2, 1987
Creator: Moran, M.J.
Partner: UNT Libraries Government Documents Department

Theoretical studies on the beam position measurement with button-type pickups in APS

Description: The response of electrostatic button-type pickups for the measurement of the transverse position of charged particle beams was investigated and analytical formulae were obtained for the signal as a function of time t and the coordinates of the beam and the electrodes. The study was done for beam pipes of circular and elliptic cross sections, for rectangular and nonrectangular electrodes, and for several cases of longitudinal beam profiles. The numerical results show good agreement with the analytical results, except that the presence of the photon beam channel and the antechamber causes finite offset ({approximately}20 {mu}m) of the electrical center in the horizontal direction. Time domain analysis indicates that the error in the measurement of the beam position using circular electrodes as compared to rectangular ones was found to be less than 100 {mu}m per 1 cm of beam excursion from the center of the beam pipe for the case of APS storage ring vacuum chamber. 5 refs., 4 figs.
Date: January 1, 1991
Creator: Chung, Y.
Partner: UNT Libraries Government Documents Department

Reduction of X-BPM systematic errors by modification of lattice in the APS storage ring.

Description: With recent developments, X-ray beam position monitors (BPMs) are capable of making accurate photon position measurements down to the sub-micron level. The true performance of X-ray beam position monitors when installed on insertion device beamlines is, however, severely limited due to the stray radiation traveling along the beamline that contaminates the insertion device photons. The stray radiation emanates from upstream and downstream dipole magnet fringe fields, from steering correctors, and from sextupoles and quadrupoles with offset trajectories. While significant progress has been made at the APS using look-up tables derived from translation stage scans to compensate for this effect, performance of ID X-BPMs to date is at the 10 to 20 micron level. A research effort presently underway to address this issue involves the introduction of a chicane into the accelerator lattice to steer the stray radiation away from the X-ray BPM blades. A horizontal parallel translation of the insertion device allows only ID photons and radiation from two nearby correctors to travel down the beamline, simplifying the radiation pattern considerably. A detailed ray tracing analysis has shown that stray radiation gets displaced by up to 2 cm horizontally at the X-BPM locations so that it can be easily masked. Results from such a modified lattice, implemented for one of the insertion devices, are reported here.
Date: April 20, 1999
Creator: Decker, G.
Partner: UNT Libraries Government Documents Department

Rat mammary carcinogenesis following neutron- or x-radiation

Description: From effects of neutron irradiation upon cell function; Neuherberg, F. R. Germany (20 Oct 1973). Sprague-Dawley female rats, 61 to 63 days of age, were given a single dose of either 0.10, 0.40, 1.6, or 6.4 rads of 0.43-MeV neutrons, or 28, 56, or 85 rads of 250-kVp x rays, or no radiation in a single experiment. The interim results, either in terms of percent of rats with mammary neoplasia or mean number of mammary neoplasms per rat, at the end of 14 months after irradiation, indicate that 0.10 to 0.40 neutron rads was followed by a mammary neoplastic response much like that following 28 xray rads. The mammary neoplastic response to either 6.4 neutron rads or 56 to 85 x-ray rads was similar. Thus the RBE for neutrons for the induction of mammary neoplasia in the SpragueDawley rat is much larger at low neutron doses than at high doses. (auth)
Date: January 1, 1973
Creator: Shellabarger, C.J.; Kellerer, A.M.; Rossi, H.H.; Goodman, L.J.; Brown, R.D.; Mills, R.E. et al.
Partner: UNT Libraries Government Documents Department

Stage III dislocation pinning in silver resulting from gamma irradiation

Description: A brief summary of the history of research in the fields of radiation damage, point defects, and dislocation effects is presented. Theory and previous experiments are discussed. Apparatus capable of continuously measuring changes in the elastic modulus and internal friction during gamma irradiation over the temperature range from <4 deg K to well above room temperature is described. A novel hollow-cylinder sample geometry permits use of a source strength of only 1 Ci. Survey experiments over a wide temperature range and isothermal irradiations above room temperature are discussed. Results are explained in terms of the KoehlerGranato- Luecke vibrating-string dislocation model and the Thompson- Buck- Huntington- Barnes defect-dislocation interaction model. Consistent results are obtained under the assumptions of wide dislocation splitting and the presence of two dislocation components. Long-range migration appears to-occur first in Stuge I in silver. The activation energy for the observed Stage III annealing is about 0.48 eV. The responsible defect is most likely the single interstitial atom. Pipe diffusion is necessary to explain the results. The trapping efficiency of dislocations could not be determined because of the presence of more than one dislocation component. (27 figures, 9 tables, 157 references) (DLC)
Date: November 14, 1973
Creator: Van Konynenburg, R.A.
Partner: UNT Libraries Government Documents Department

Echo-seeding options for LCLS-II

Description: The success of LCLS has opened up a new era of x-ray sciences. An upgrade to LCLS is currently being planned to enhance its capabilities. In this paper we study the feasibility of using the echo-enabled harmonic generation (EEHG) technique to generate narrow bandwidth soft x-ray radiation in the proposed LCLS-II soft x-ray beam line. We focus on the conceptual design, the technical implementation and the expected performances of the echo-seeding scheme. We will also show how the echo-seeding scheme allows one to generate two color x-ray pulses with the higher energy photons leading the lower energy ones as is favored in the x-ray pump-probe experiments.
Date: September 14, 2010
Creator: Xiang, Dao
Partner: UNT Libraries Government Documents Department