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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Algorithms to automate gap-dependent integral tuning for the 2.8-meter long horizontal field undulator with a dynamic force compensation mechanism

A 2.8-meter long horizontal field prototype undulator with a dynamic force compensation mechanism has been developed and tested at the Advanced Photon Source (APS) at Argonne National Laboratory (Argonne). The magnetic tuning of the undulator integrals has been automated and accomplished by applying magnetic shims. A detailed description of the algorithms and performance is reported.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

The PETRA III extension

The 3{sup rd} generation low-emittance 6 GeV PETRA III facility has been substantially modified to add new beamlines. This extension project involved the complete removal and reconstruction of part of the storage ring with a double-bend achromat lattice as well as the construction of two new experimental halls. Making use of two long straight sections and a canted undulator scheme in the rebuilt arcs, up to ten new insertion device beamlines can be accommodated. In the current phase of the project, seven insertion device and one bending magnet beamline are being implemented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Magnet system optimization for segmented adaptive-gap in-vacuum undulator

Segmented Adaptive Gap in-vacuum Undulator (SAGU), in which different segments have different gaps and periods, promises a considerable spectral performance gain over a conventional undulator with uniform gap and period. According to calculations, this gain can be comparable to the gain achievable with a superior undulator technology (e.g. a room-temperature in-vacuum hybrid SAGU would perform as a cryo-cooled hybrid in-vacuum undulator with uniform gap and period). However, for reaching the high spectral performance, SAGU magnetic design has to include compensation of kicks experienced by the electron beam at segment junctions because of different deflection parameter values in the segments. Here we show that such compensation to large extent can be accomplished by using a passive correction, however, simple correction coils are nevertheless required as well to reach perfect compensation over a whole SAGU tuning range. Magnetic optimizations performed with Radia code, and the resulting undulator radiation spectra calculated using SRW code, demonstrating a possibility of nearly perfect correction, are presented.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Development of cryogenic undulators with PrFeB magnets at SOLEIL

Short period high field undulators are of interest for X-ray brilliance enhancement in synchrotron radiation applications and for compact Free Electron Lasers. Cryogenic in-vacuum undulators [1] are one of the possible solutions. At SOLEIL, PrFeB magnets were directly chosen, even if still under development at that time. Indeed, they enable to avoid the spin transition reorientation phenomenon which occurs with NdFeB magnets [2] and the magnets can be cooled down directly at 77 K. The first selected grade CR53 from Hitachi presents a remanence of 1.35 T at 293 K and 1.57 T at 77 K, with a coercivity of 1355 kA/m at 293 K and 6000 kA/m at 77 K. A 2 m long cryogenic undulator of period 18 mm was first built in-house, with a specific Hall probe bench directly installed in the final vacuum chamber. This first cryogenic undulator has been in operation on the storage ring for 4 years [3]. A second U18 cryo-ready undulator using a slightly different magnet grade with a higher coercivity and modules with magnets surrounded by two half poles for easier magnetic optimization is under construction. A third 3 m long cryo-ready undulator U15 with a period of 15 mm is under development. It will be first used for the LUNEX5 FEL [4, 5] project (COXINEL demonstration of FEL amplification with a laser wakefield acceleration [6]). The measurement bench will include a correction of the Hall probe position and angle, the field integrals will be measured with a stretched wire.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Conceptual design of front ends for the advanced photon source multi-bend achromats upgrade

The proposed Advanced Photon Source (APS) upgrade from a double-bend achromats (DBA) to multi-bend achromats (MBA) lattice with ring energy change from 7 GeV to 6 GeV and beam current from 100 mA to 200 mA poses new challenges for front ends. All front ends must be upgraded to fulfill the following requirements: 1) handle the high heat load from two insertion devices in either inline or canted configuration, 2) include a clearing magnet in the front end to deflect and dump any electrons in case the electrons escape from the storage ring during swap-out injection with the safety shutters open, 3) incorporate the next generation x-ray beam position monitors (XBPMs) into the front end to meet the new stringent beam stability requirements. This paper presents the evaluation of the existing APS front ends and standardizes the insertion device (ID) front ends into two types: one for the single beam and one for the canted beams. The conceptual design of high heat load front end (HHLFE) and canted undulator front end (CUFE) for APS MBA upgrade is presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Generation of X-Ray Radiation in Free-Electron Lasers with Two-Frequency Undulators

The possibility of creating an x-ray laser with a two-frequency undulator with the help of the phenomenological model of a single-pass free-electron laser (FEL) that takes into account the beam characteristics and the undulator field is studied. The model is used to analyze the FEL dynamics, and the simulation results are compared with the experimental data. The advantages of using a two-frequency undulator in the single-pass FEL and the possibility of generating powerful x-ray radiation in it are demonstrated. The evolution of power of higher-harmonic generation in the FEL and the bunching coefficient at wavelengths of these harmonics are studied. The possibility of their further amplification until saturation in a cascade FEL matched to higher harmonics of the two-frequency undulator is demonstrated.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Multicascade X-Ray Free-Electron Laser with Harmonic Multiplier and Two-Frequency Undulator

The feasibility of generation of powerful x-ray radiation by a cascade free-electron laser (FEL) with amplification of higher harmonics using a two-frequency undulator is studied. To analyze the FEL operation, a complex phenomenological single-pass FEL model is developed and used. It describes linear and nonlinear generation of harmonics in the FEL with seed laser that takes into account initial electron beam noise and describes all main losses of each harmonic in each FEL cascade. The model is also calibrated against and approved by the experimental FEL data and available results of three-dimensional numerical simulation. The electron beam in the undulator is assumed to be matched and focused, and the dynamics of power in the singlepass FEL with cascade harmonic multipliers is investigated to obtain x-ray laser radiation in the FEL having the shortest length, beam energy, and frequency of the seed laser as low as possible. In this context, the advantages of the two-frequency undulator used for generation of harmonics are demonstrated. The evolution of harmonics in a multicascade FEL with multiplication of harmonics is investigated. The operation of the cascade FEL at the wavelength λ = 1.14 nm, generating ~30 MW already on 38 m with the seed laser operating at a wavelength of 11.43 nm corresponding to the maximal reflectivity of the multilayered mirror MoRu/Be coating is investigated. In addition, the operation of the multicascade FEL with accessible seed UVlaser operating at a wavelength of 157 nm (F2 excimer UV-laser) and electron beam with energy of ~0.5 GeV is investigated. X-ray radiation simulated in it at the wavelength λ ~ 3.9 nm reaches power of ~50 MW already at ~27 m, which is by two orders of magnitude shorter than 3.4 km of the x-ray FEL recently put into operation in Europe.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

The analysis of Raman scattering in a free-electron laser with a rectangular hybrid wiggler

A one dimensional theory of the stimulated Raman backscattering process in a free electron laser with rectangular hybrid wiggler (RHW) is analyzed. The dispersion relation in the rest frame of the electron beam and also a formula for the lab-frame spatial growth rate are derived. A numerical computation of the growth rate for RHW is conducted and a comparison with that for coaxial hybrid wiggler is made away from the resonance. The growth rate is found larger for the rectangular wiggler than for the coaxial wiggler. A much narrower magnetoresonance associated with the third spatial harmonic is also obtained compared to the first one.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Compact scanning transmission x-ray microscope at the photon factory

We report the design and performance of a compact scanning transmission X-ray microscope developed at the Photon Factory. Piezo-driven linear stages are used as coarse stages of the microscope to realize excellent compactness, mobility, and vibrational and thermal stability. An X-ray beam with an intensity of ∼10{sup 7} photons/s was focused to a diameter of ∼40 nm at the sample. At the soft X-ray undulator beamline used with the microscope, a wide range of photon energies (250–1600 eV) is available. The microscope has been used to research energy materials and in environmental sciences.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Laser wakefield accelerated electron beam monitoring and control

We will discuss our participation in the ImPACT project, which has as one of its goals the development of an ultra-compact electron accelerator using lasers (< 1 GeV, < 10 m) and the generation of an x-ray beam from the accelerated electrons. Within this context we will discuss our investigation into electron beam monitoring and control. Since laser accelerated electrons will be used for x-ray beam generation combined with an undulator, we will present investigation into the possibilities of the improvement of electron beam emittance through cooling.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

The FERMI seeded-FEL facility: Status and perspectives

The FERMI Free Electron Laser (FEL) in Trieste, Italy operates in the extreme ultraviolet and soft x rays (EUV-SXR) wavelength range delivering high-fluence, stable, ultra-short pulses. Its unique design based on a seeded scheme and on tunable undulators allows unprecedented control of pulse parameters such as wavelength, phase, polarization, synchronization, pulse duration and implementation of multi-color FEL schemes. Both FEL-1 and FEL-2 lines with nominal wavelength range 100–20 nm and 20–4 nm, respectively, are open to users. We report on the unique features of FERMI, in particular those that have evolved beyond the original design, and on their application to pioneering experiments. We also present the upgrades that are planned to further expand the capabilities of this unique light source.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

FLASH2: Operation, beamlines, and photon diagnostics

FLASH2, a major extension of the soft X-ray free-electron laser FLASH at DESY, turns FLASH into a multi-user FEL facility. A new undulator line is located in a separate accelerator tunnel and driven additionally by the FLASH linear accelerator. First lasing of FLASH2 was achieved in August 2014 with simultaneous user operation at FLASH1. The new FLASH2 experimental hall offers space for up to six experimental end stations, some of which will be installed permanently. The wide wavelength range spans from 4-60 nm and 0.8 nm in the 5{sup th} harmonic and in the future deep into the water window in the fundamental. While this is of high interest to users, it is challenging from the beamline instrumentation point of view. Online diagnostics - which are mostly pulse resolved - for beam intensity, position, wavelength, wave front, and pulse length have been to a large extent developed at FLASH(1) and have now been optimized for FLASH2. Pump-probe facilities for XUV-XUV, XUV optical and XUV-THz experiments will complete the FLASH2 user facility.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

EPU correction scheme study at the CLS

The Canadian Light Source (CLS) Quantum Materials Spectroscopy Center (QMSC) beamline will employ a novel double period (55 mm, 180 mm) elliptically polarizing undulator (EPU) to produce photons of arbitrary polarization in the soft X-ray regime. The long period and high field of the 180 mm period EPU will have a strong dynamic focusing effect on the storage ring electron beam. We have considered two partial correction schemes, a 4 m long planar array of BESSY-II style current strips, and soft iron L-shims. In this paper we briefly consider the implementation of these correction schemes.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Properties of the insertion devices for PETRA III and its extension

DESY presently operates 14 independent insertion device (ID) beamlines at its 6 GeV storage ring PETRA III. Besides the 2 m long standard undulators U29 and U32, several special IDs of up to 5 m length have been installed to meet the experimental requests for high energy X-rays, elliptically polarized light, and a higher degree of coherence. Two additional half octants of the ring have recently been reconstructed, in order to extend the experimental capabilities at PETRA III. The straight sections also allow for installation of IDs of 2 m or 5 m length. This article gives an overview of the ID key parameters, the spectral properties and the brilliance of the current undulators installed at PETRA III. It also presents the characteristics of some of the upcoming special IDs, like in-vacuum and short undulators.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Data analysis of photon beam position at PLS-II

In the third generation light source, photon beam position stability is critical issue on user experiment. Generally photon beam position monitors have been developed for the detection of the real photon beam position and the position is controlled by feedback system in order to keep the reference photon beam position. In the PLS-II, photon beam position stability for front end of particular beam line, in which photon beam position monitor is installed, has been obtained less than rms 1μm for user service period. Nevertheless, detail analysis for photon beam position data in order to demonstrate the performance of photon beam position monitor is necessary, since it can be suffers from various unknown noises. (for instance, a back ground contamination due to upstream or downstream dipole radiation, undulator gap dependence, etc.) In this paper, we will describe the start to end study for photon beam position stability and the Singular Value Decomposition (SVD) analysis to demonstrate the reliability on photon beam position data.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Project to renew the undulators at the photon factory

At the 2.5-GeV Photon Factory (PF) storage ring, we recently constructed four new undulators known as U#02-2, U#13, SGU#15, and U#28 for BL02, BL13, BL15, and BL28, respectively. SGU#15 is an in-vacuum undulator with a period length of 17.6 mm. The other three undulators are elliptically polarizing undulators (EPUs) for the vacuum ultraviolet and soft X-ray (VUV-SX) light sources to obtain various polarization states. We constructed these new undulators by fiscal 2013 and step by step installed them in the PF ring. We describe the details of the construction of these new undulators in this report.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Status of the LCLS-II undulators

The new free electron laser facility Linear Coherent Light Source II (LCLS-II) under construction at SLAC National Accelerator Laboratory will use planar variable gap undulators of hybrid type for the production of free electron laser (FEL) radiation. The LCLS-II will include two FELs with two separate rows of undulators to generate soft and hard x-rays. The soft x-rays will be produced by undulators with 39 mm period length (SXR) and the hard x-rays will be produced by undulators with 26 mm period length (HXR). Both the SXR and the HXR undulators are 3.4 m long and they use a common support structure and frame. In total 21 SXR and 32 HXR undulators will be produced by Lawrence Berkeley National Laboratory in collaboration with SLAC National Accelerator Laboratory. A full-scale prototype with 32 mm period length, called HXU, has been assembled at Lawrence Berkeley National Laboratory (LBNL). The present status of the design, prototyping, and pre-series production of the SXR and HXR undulators are presented in this paper together with the first results from measurements on the full scale HXU prototype.

43 PARTICLE ACCELERATORS↗