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A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from ~0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

A 0.27 meV-bandwidth monochromator for 21.5 keV synchrotron radiation demonstrates exceptional stability using cryogenic stabilization and active feedback control., A high-resolution silicon monochromator suitable for 21.541 keV synchrotron radiation is presented that produces a bandwidth of 0.27 meV. The operating energy corresponds to a nuclear transition in 151Eu. The first-of-its-kind, fully cryogenic design achieves an energy-alignment stability of 0.017 meV r.m.s. per day, or a 100-fold improvement over other meV-monochromators, and can tolerate higher X-ray power loads than room-temperature designs of comparable resolution. This offers the potential for significantly more accurate measurements of lattice excitation energies using nuclear resonant vibrational spectroscopy if combined with accurate energy calibration using, for example, high-speed Doppler shifting. The design of the monochromator along with its performance and impact on transmitted beam properties are presented.

Computer simulations using a continuous change in particle energy are an important tool in improving the performance at the final stage of the Linac Coherent Light Source (LCLS) undulator line. Changes in the particle energy cause the break length between undulator segments to no longer be optimized. Radiation losses less than 0.1%/undulator segment can be easily compensated by adjustment of an undulator deflection parameter K. For higher losses, up to 0.4%, adjustment of K can still be compensated, but careful optimization is required. Compensating for losses greater than 0.4% requires tapering of the field within the undulator segment. The LCLS undulator segments are in mass production at this time. The first two undulators for the LCLS project were delivered to the APS magnetic measurement facility. They have already been tuned, and meet all requirements for the LCLS free-electron laser (FEL). The final results of this tuning will be presented, with emphasis on the FEL-specific requirements. A systematic zero shift in the Sentron [ 〈http://www.sentron.ch/〉 . [1] ] 2-axis Hall probe was discovered, which required correction in order to obtain the proper field integrals.

The design of a new hybrid-type undulator with a fixed gap of 6.4 mm, a period of 30 mm and a length of 3.4 m is presented. The fractional variations in deflection parameter K between segments of 130.4-m-long undulator line for the Linac Coherent Light Source (LCLS) must be ⩽1.5×10−4. Major design features and their choices are discussed. Lessons learned while working with this prototype are critical for successful project execution. Although the prototype undulator met all of the LCLS specifications, development continued in order to simplify the system. A canted-pole geometry was adopted, which allows the K value to be changed by lateral translation of the entire undulator segment. The prototype undulator was subsequently modified to test the canted-pole concept. Magnetic measurements demonstrated that the undulator with canted poles meets all LCLS specifications and is more cost effective to implement.

A full-length 30-mm-period prototype undulator segment has been constructed for the Linac Coherent Light Source (LCLS) project. It is a 3.42-m-long planar permanent magnet hybrid device with a fixed gap near 6.35 mm. The magnetic structure was assembled from a set of 500 magnets that were purchased from Shin-Etsu. A subset of the magnets was measured in a Helmholtz coil system to check the accuracy of the vendor's measurements of the magnetic moments. A specially designed half-period fixture was used for Hall probe measurements of the magnetic field of all the magnet blocks. The magnets were sorted based on the vendor's data of the total magnetic moment and our measurements of the field integrals. The trajectory calculated from Hall probe measurements of the assembled device was within the specified tolerance (deviation

The Low-Energy Undulator Test Line (LEUTL) at the Advanced Photon Source, Argonne National Laboratory, is intended to demonstrate the basic operation of a SASE-based free-electron laser. Goals include comparison of experimental results With theoretical predictions and scaling laws, identification of problems relevant to fourth-generation light source construction and operation and the means of addressing them, the development of operational and diagnostic techniques to optimize SASE FEL performance and increase repeatability from run to run. and performance of initial pioneering experiments capable of exploiting the unique properties of the laser. The basic layout and operational philosophy of the LEUTL experiment is presented. A summary of past results, including saturation, is reviewed, and a description of recent results is presented. We conclude with future plans, which include pressing to shorter wavelengths and incorporating user experiments into the LEUTL experimental program. (Less)

Currently, a Linac Coherent Light Source (LCLS) prototype undulator is under construction. The prototype is a 3.4-m-long hybrid-type undulator with fixed gap of 6 mm. The period length is 30 mm and the number of poles is 226. For this undulator, 450 NdFeB magnet blocks are used. This project does not have demanding requirements for multipole component errors, but the field strength at x =0 should be as precise as possible to provide proper particle steering and phase errors. The first set of magnetic blocks has been measured. The strength and direction of magnetization of the magnet blocks are measured using a Helmholtz coil system. In addition to this, Hall probe measurements are performed for magnet blocks while they are mounted in a specially designed cassette with vanadium-permendur poles. The magnet blocks will be sorted using these data to minimize errors. Computer simulations show that magnets may be sorted in decreasing strengths with little or no additional tuning of the undulators.

The Advanced Photon Source self-amplified spontaneous emission (SASE) free-electron laser (FEL) uses diagnostics between undulator sections to characterize the light and the electron beam. These diagnostics enable z-dependent measurements of the exponential growth of the radiation and of the microbunching. The original diagnostics were designed for visible light. To enable measurements down to 265 nm, UV-enhanced cameras and fused-silica lenses have been installed. We have now designed a diagnostics suite that will enable us to continue measurements down to 50 nm using reflective optics and back-illuminated CCD cameras operating in vacuum. We describe the enhancements to the diagnostics for operation in the UV and VUV.

A short prototype (847-mm-long) of an Insertion Device (ID) with the dynamic compensation of ID magnetic forces has been designed, built, and tested at the Advanced Photon Source (APS) of the Argonne National Laboratory. The ID magnetic forces were compensated by the set of conical springs placed along the ID strongback. Well-controlled exponential characteristics of conical springs permitted a very close fit to the ID magnetic forces. Several effects related to the imperfections of actual springs, their mounting and tuning, and how these factors affect the prototype performance has been studied. Finally, series of tests to determine the accuracy and reproducibility of the ID magnetic gap settings have been carried out. Based on the magnetic measurements of the ID Beff, it has been demonstrated that the magnetic gaps within an operating range were controlled accurately and reproducibly within ±1 μm. Successful tests of this ID prototype led to the design of a 3-m long device based on the same concept. The 3-m long prototype is currently under construction. It represents R&D efforts by the APS toward APS Upgrade Project goals as well as the future generation of IDs for the Linac Coherent Light Source (LCLS).

Exponential growth of self-amplified spontaneous emission at 530 nm was first experimentally observed at the Advanced Photon Source low-energy undulator test line in December 1999. Since then, further detailed measurements and analysis of the results have been made. Here, we present the measurements and compare these with calculations based on measured electron beam properties and theoretical expectations.

Three vacuum chambers for the VUV SASE FEL undulator sections at the TESLA Test Facility (TTF) were designed, built, tested and installed. Each chamber is 4.5 m long and of 11.5 mm thick. The inner diameter of the beam pipe is 9.5 mm. The rectangular chamber pro"le with a width of 128 mm is used to integrate beam position monitors and steerers. This is needed to provide a good overlap between the electron and the photon beam over the entire undulator length. The chambers are built in an aluminum extrusion technology developed for the insertion device vacuum chambers of the Advanced Photon Source. After manufacturing, special processing was performed to reach low outgassing rates ((1]10~11mbar) l/s) cm2) and particle-free chambers. Mounting of the chambers at TTF were performed under clean room conditions better class 100. ( 2000 Elsevier Science B.V. All rights reserved.

A self-amplified spontaneously emitting (SASE) free-electron laser (FEL) for the visible-to-ultraviolet spectral range is under construction at the Advanced Photon Source at Argonne National Laboratory. The amplifier part of the FEL consists of twelve identical 2.7-m-long sections. Each section includes a 2.4-m-long, 33-mm-period hybrid undulator, a quadrupole lens, and a set of electron beam and radiation diagnostics equipment. The undulators will operate at a fixed magnetic gap (approx. 9.3 mm) with K=3.1. The electron beam position will be monitored using capacitive beam position monitors, YAG scintillators with imaging optics, and secondary emission detectors. The spatial distribution of the photon beam will be monitored by position sensitive detectors equipped with narrow-band filters. A high-resolution spectrograph will be used to observe the spectral distribution of the FEL radiation.

A Low-Energy Undulator Test Line (LEUTL) is under construction at the Advanced Photon Source (APS). Its purpose is to fully characterize innovative, future-generation undulators, and to act as a test line in pursuit of generating coherent radiation at wavelengths down to a few tens of nanometers. The line will use a high-brightness RF electron gun as its source and the APS linac to accelerate these electrons up to >650 MeV. This beam will then be directed through undulators located in a new 50 m long enclosure. In addition, there is an end station external to the radiation environment which will house the equipment necessary to directly study the light generated by the beam and undulator system. At present, the new enclosures are complete, the electron rf gun is installed and operational, and a part of the necessary transport line is installed. A prototypical undulator cell, suitable for testing the requirements of single-pass free-electron laser operation, is near completion and will be installed during the winter shutdown of 1998. This paper will describe the LEUTL project and, in particular, its capabilities for exploring the self-amplified spontaneous emission process.

We present a pulsed-magnet system that enables x-ray single-crystal diffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closed-cycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to $\sim 30$ T with a zero-to-peak-field rise time of $\sim$2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle ($\sim 23.6^\circ$) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets, and offers a practical solution for preserving optical access in future higher-field pulsed magnets., Comment: Accepted for publication in Rev. Sci. Instrum

In the present work the SR beam lines at the TNK are described. Two types of SR beam lines are considered: for radiation from strong-field superconducting wigglers in the 0.2–5 A wavelength range and for radiation from bending magnets, undulators and multipole wigglers in the 5–2000 A range.

Modern SR sources are dedicated for a wide use of bright and intense radiation from insertion devices. Here the description, the conceptual design and the parameters of a multipole wiggler and an undulator are given for a new storage ring TNK for microelectronics applications.

A general presentation on the main storage ring of the Zelenograd Technological Research Center is given. The TNK SR source is intended to create a basis for the industrial realization of advanced X-ray lithographic technology. A modern analytical center for materials science will be established, based on the TNK facility.

The use of circularly polarized radiation is advantageous for the study of magnetic materials using x‐ray scattering techniques. The APS is an ideal source of x‐ray radiation for such studies. We present a description of the elliptical multipole wiggler (EMW) [S. Yamamoto, H. Kawata, H. Kitamura, and M. Ando, Phys. Rev. Lett. 62, 2672 (1989)] to be constructed at the APS. This device has been chosen for reasons of tunability and special polarization properties. This insertion device is capable of producing circularly polarized x rays on axis. The EMW period will be λu=16 cm, the number of full strength poles in the hybrid structure is 31, and the device length is 2.8 m. The hybrid magnetic structure produces a peak vertical magnetic field with Ky=14 and the electromagnet provides horizontal magnetic field with Kx=1–2. The frequency of the horizontal field change is up to 10 Hz. The beamline will consist of three stations operating in tandem with only one station receiving x rays at any one time. The three...

A design of a special synchrotron radiation absorber for the storage ring VEPP-4M is presented. The density of the synchrotron radiation power on the absorber surface is up to 500 W/mm 2 . The absorber is made from a beryllium plate, brazed inside to the copper vacuum chamber, which is intensively water-cooled from outside.

A vacuum system for the Advanced Photon Source elliptical multipole wiggler (EMW) that will operate at a pressure of 10−9 Torr with a storage ring current of 100 mA at 7.0 GeV has been designed and is being fabricated. The major part of the system is a stainless steel chamber with a 66.6 mm by 19.6 mm rectangular cross section. The length of the vacuum chamber is 3100 mm, and the wall thickness is 1.2 mm. Two versions of the vacuum chamber will be produced: with and without distributed nonevaporable getter (NEG) pumping. The version with NEG pumping will have slides on the top and bottom walls to accommodate sintered plates available from SAES. To activate these plates, the entire vacuum chamber will be baked from the outside up to a temperature of 350° C–450 °C. Provision for the baking is included in the design of the vacuum system, its support, and in the EMW itself. The complexity introduced into the design by the need for external activation of the NEG plates is eliminated in the design of the second...

Today, many bright photon beams in the ultraviolet and x-ray wavelength range are produced by insertion devices installed in specially designed third-generation storage rings. There is the possibility of producing photon beams that are orders of magnitude brighter than presently achieved at synchrotron sources, by using self-amplified spontaneous emission (SASE). At the Advanced Photon Source (APS), the low-energy undulator test line (LEUTL) free-electron laser (FEL) project was built to explore the SASE process in the visible through vacuum ultraviolet wavelength range. While the understanding gained in these experiments will guide future work to extend SASE FELs to shorter wavelengths, the APS FEL itself will become a continuously tunable, bright light source. Measurements of the SASE process to saturation have been made at 530 and 385 nm. A number of quantities were measured to confirm our understanding of the SASE process and to verify that saturation was reached. The intensity of the FEL light was me...

The first undulator radiation has been extracted from the Advanced Photon Source (APS). The results from the characterization of this radiation are very satisfactory. With the undulator set at a gap of 15.8 mm (K=1.61), harmonics as high as the 17th were observed using a crystal spectrometer. The angular distribution of the third-harmonic radiation was measured, and the source was imaged using a zone plate to determine the particle beam emittance. The horizontal beam emittance was found to be 6.9 {plus_minus} 1.0 nm-rad, and the vertical emittance coupling was found to be less than 3%. The absolute spectral flux was measured over a wide range of photon energies, and it agrees remarkably well with the theoretical calculations based on the measured undulator magnetic field profile and the measured beam emittance. These results indicate that both the emittance of the electron beam and the undulator magnetic field quality exceed the original specifications.

A general presentation on the main storage ring of the SRS complex SIBERIA is given. The facility will consist of the 2.5 GeV electron ring SIBERIA-2 with 12 straight sections to accomodate insertion devices. The magnetic lattice is optimized to achieve high btightness of SR. A low horizontal emittance of 7.65×10 −6 cm rad is obtained.

The storage ring Siberia-1 was put into operation as a dedicated source of synchrotron radiation at the Kurchatov Institute (Moscow) in 1983. It was designed and built at the Institute of Nuclear Physics (Novosibirsk) [1]. The critical wavelength of the radiation from the bending magnets with an electron beam in the Siberia-1 of E = 450 MeV is λc = 61 A. This radiation has been used for experiments since 1985. In May 1985 the radiation with λc = 21 A was obtained from a three-pole superconducting snake. The maximum field on the beam orbit is 4.3 T. In the present paper the design of the snake magnet and its arrangement in the storage ring are presented as well as the results of the stand test and of the study concerning the influence of the snake on the particle motion in the storage rings.

In the last decade researches dealing with the creation of technology for X-ray lithography and for appropriate production equipment have been performed in many countries. The basic aim of these works is to provide a mass production of inexpensive devices with submicron structures (0.7-0.1 μm). Bringing X-ray lithographic technology into commercial practice necessitates to design and build a dedicated SR source for the electronic industry. The use of superconducting bending magnets with 40–70 kG field strength enables the storage ring circumference to be reduced by a factor of 2–5 and the injection energy by a factor of 3—4 as compared to the conventional designs of storage rings. In the present paper we consider a storage ring which was designed for a maximum energy of 600 MeV, with 60 kG field strength in its bending magnets and 10 m circumference. The critical SR wavelength is 8.6 A. The electrons are injected into the storage ring at 50–60 MeV and the maximum stored current is assumed to be equal to 0.3 A.

The paper deals with two projects of compact superconducting storage rings for industrial production of integrated circuits (IC) using x‐ray lithography within the 8‐ to 20‐A wavelengths range. The azimuthally symmetric superconducting storage ring Siberia‐AS at an energy of 600 MeV is a superconducting analog of VEP‐1, one of the earliest storage rings in the world intended for the purposes of high‐energy physics. Unlike the conventional design, no iron yoke is used in the storage ring under consideration to form the magnetic field at the equilibrium orbit and to close the return magnetic flux—this is performed by some inner and outer superconducting windings. Such a scheme enables the size of the storage ring to be substantially reduced (a cylinder of 2 m in diameter and 2 m long), and as a result, its weight decreases, too (about 10 tons). The eight‐magnet storage ring Siberia‐SM is of four‐order symmetry so that the periodicity element comprises two rectangular magnets and three lenses. Its basic comp...

A polarimeter for soft X-rays and VUV radiation is described. Two Bragg reflectors at 45° incidence angle are used in the polarimeter. Multilayer mirrors with a suitable period and number of layers are chosen as reflectors. The polarimeter was tested on VEPP-2M storage ring with SR from a bending magnet and from the helical undulator.

A new Rowland monochromator with a fixed output slit, which operates according to the grazing‐incidence scheme, is described. The device is notable for the capability to change the Rowland radius within 1–3 m. The monochromator was tested using synchrotron radiation from the storage ring VEPP‐2M.

Two types of electromagnetic undulators are described. The first one has 33.5 periods with a length of 10 cm and a magnetic field amplitude of 5.3 kG. The other, developed for future FEL experiments, has 39.5 periods with 7 cm length and a magnetic field amplitude of 55 kG.