Euclid TechLabs, LLC, Solon, Ohio, USA
ANL, Argonne, USA
CERN, Geneva, Switzerland
In the past decade, tremendous efforts have been put into the development of the CLIC Power Extraction and Transfer Structure (PETS), and significant progress has been made. However, one concern remains the manufacturing cost of the PETS, particularly considering the quantities needed for a TeV machine. A dielectric-based wakefield power extractor in principle is much cheaper to build. A low surface electric field to gradient ratio is another big advantage of the dielectric-loaded accelerating/decelerating structure. We are currently investigating the possibility of using a cost-effective dielectric-based wakefield power extractor as an alternative to the CLIC PETS. We designed a 12 GHz dielectric-based power extractor which has a similar performance to CLIC PETS with parameters 23 mm beam channel, 240 ns pulse duration, 135 MW output per structure using the CLIC drive beam. In order to study potential rf breakdown issues, as a first step we are building a 11.424 GHz dielectric-based power extractor scaled from the 12 GHz version, and plan to perform a high power rf test using the SLAC 11.424 GHz high power rf source.
ANL, Argonne, USA
Recently, a grazing-incidence insertion device x-ray beam position monitor (GRID-XBPM) was proposed for the intense x-ray beam from the future APS undulators [*]. By combining the function of limiting aperture with the XBPM, it increases the power-bearing capacity of the XBPM and, at the same time, eliminates the problem of relative alignment of the two critical components in the beamline. Furthermore, by imaging the hard x-ray fluorescence footprint on the collimator, the XBPM is immune to the soft x-ray background, and its accuracy is improved at larger gap settings. In addition to these advantages, the GRID-XBPM can also be implemented to measure center-of-mass of the x-ray fluorescence footprint when pinhole-camera-like optics are used for position readout*. This offers a solution for long-standing XBPM design issues for elliptical undulators, which have a donut-shaped power distribution. In this work, we report design progress for the GRID-XBPM for the high-power elliptically polarized undulator planned for the APS intermediate energy x-ray (IEX) beamline. Computer simulation of its performance and experimental tests from a scale model system will also be presented.
* B.X. Yang, G. Decker, S. H. Lee, and P. Den Hartog, Beam Instrumentation Workshop, Santa Fe, 2010, to be published.
BNL, Upton, Long Island, New York, USA
ANL, Argonne, USA
Case Western Reserve University, Center for Synchrotron Biosciences, Upton, New York, USA
LANL, Los Alamos, New Mexico, USA
SBU, Stony Brook, New York, USA
Stony Brook University, Stony Brook, USA
Modern synchrotrons are capable of significant per-pulse x-ray flux, and time resolved pulse-probe experiments have become feasible. These experiments provide unique demands on x-ray monitors, as the beam position, flux and arrival time all potentially need to be recorded for each x-ray pulse. Further, monitoring of “white” x-ray beam position and flux upstream of beamline optics is desirable as a diagnostic of the electron source. We report on a diamond quadrant monitors which provide beam monitoring for a variety of applications, for both white and monochromatic beams. These monitors have a position resolution of 20 nm for a stable beam, are linear in flux over at least 11 orders of magnitude, and can resolve beam motion shot-by-shot at repetition rates up to 6.5 MHz.
LBNL, Berkeley, California, USA
The Advanced Light Source (ALS) at Berkeley Lab is one of the earliest 3rd generation light sources. Over the years substantial upgrades have been implemented to keep the facility at the forefront of soft x-ray sources. The most recent one is a multi-year upgrade, that includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade, which will reduce the horizontal emittance from 6.3 to 2.2 nm. This will result in a brightness increase by a factor of three for bend magnet beamlines and at least a factor of two for insertion device beamlines and will keep the ALS competitive with newer sources.
PAL, Pohang, Kyungbuk, Republic of Korea
In order to meet the domestic Korean synchrotron user’s requirements demanding high beam stability and extended photon energies, PLS-II upgrade program has been launched in January 2009 through a 3-year project plan. PLS-II storage ring is newly designed a modified achromatic version of Double Bend Achromat (DBA) to achieve almost twice as many straight sections as the current PLS (TBA) with a design goal of the natural emittance of 5.8 nm·rad, 3.0 GeV beam energy and 400 mA beam current. In the PLS-II, the top-up injection using full energy linac of 3.0 GeV beam energy will be routinely operated for higher stable photon beam as well and therefore the production of hard x-ray undulator radiation of 8 to13 keV is anticipated to allow for more competitive scientific research activities namely x-ray bio-imaging and protein crystallography.
FZJ, Jülich, Germany
BNL, Upton, Long Island, New York, USA
At each injection and extraction period of RHIC operation, the beam frequency will be sweeping across a wide range, and some of the harmonics will cross the frequency of the 56MHz SRF cavity. To avoid cavity excitation during these periods, a fundamental damper was designed for the quarter-wave resonator to heavily detune the cavity. The power extracted by the fundamental damper should be compliant with the cooling ability of the system at all stages. In this paper, we discussed the power output from the fundamental damper when it is fully extracted, inserted, and during its movement.
Fermilab, Batavia, USA
Yale University, Physics Department, New Haven, CT, USA
Euclid TechLabs, LLC, Solon, Ohio, USA
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
* A. Kanareykin, et al, IPAC 2010, p. 3987
** S. Kazakov, et al, “Fast Ferroelectric Phase Shifter Design For ERLs,” 45th ICFA Beam Dynamics Workshop, 2009
*** S. Kazakov, et al, PAC2007, p. 599.
Fermilab, Batavia, USA
Muons, Inc, Batavia, USA
In order to make use of ferrite and/or garnet materials in the phase and frequency locked magnetron, for which Muons, Inc., received a Phase II award, materials must be tested in two orthogonal magnetic fields. One field is from the biasing field of the magnetron, the other from the biasing field used to control the ferrite within the anode structure of the magnetron. A test fixture was built and materials are being tested to determine their suitability. The status of those material tests are reported on in this paper.
Muons, Inc, Batavia, USA
ANL, Argonne, USA
Muons, Inc, Batavia, USA
CLASSE, Ithaca, New York, USA
SLAC, Menlo Park, California, USA
Superconducting RF (SRF) systems typically contain resonances at unwanted frequencies, or higher order modes (HOM). For storage ring and linac applications, these higher modes must be damped by absorbing them in ferrite and other lossy ceramic materials. Typically, these absorbers are brazed to substrates that are often located in the drift tubes adjacent to the SRF cavity. These HOM absorbers must have broadband microwave loss characteristics and must be thermally and mechanically robust, but the ferrites and their attachments are weak under tensile and thermal stresses and tend to crack. Based on prior work on HOM loads for high current storage rings and for an ERL injector cryomodule, a HOM absorber with improved materials and design is being developed for high-gradient SRF systems. This work will use novel construction techniques (without brazing) to maintain the ferrite in mechanical compression. Attachment techniques to the metal substrates will include process techniques for fully-compressed ferrite rings. Prototype structures will be fabricated and tested for mechanical strength under thermal cycling conditions.
Texas A&M University, College Station, Texas, USA
A design is being developed to prototype for a dipole for this purpose: a block-coil dipole with 13 T short- sample field, 11 T working field, and 6 cm aperture. The dipole is a natural application of the high-field dipole strategy developed at Texas A&M, using simple pancake windings, flux-plate suppression of low-field multipoles, and bladder preloading. A short model dipole is planned.
Fermilab, Batavia, USA
Muons, Inc, Batavia, USA
A helical cooling channel (HCC) is a new technique proposed for six-dimensional (6D) cooling of muon beams. To achieve the optimal cooling rate, the high field section of HCC need to be developed, which suggests using High Temperature Superconductors (HTS). This paper updates the parameters of a YBCO based helical solenoid (HS) model, describes the fabrication of HS segments (double-pancake units) and the assembly of six-coil short HS model with two dummy cavity insertions. Three HS segments and the six-coil short model were tested. The results are presented and discussed.
BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, USA
LBNL, Berkeley, California, USA
An alternate structure for the 120mm Nb3Sn quadrupole magnet is presently under development for use in the upgrade for LHC at CERN. The design aims to build on existing technology developed in LARP with the LQ and HQ magnets and to further optimize the features required for operation in the accelerator. The structure includes features for maintaining mechanical alignment of the coils to achieve the required field quality. It also includes a helium containment vessel and provisions for cooling with 1.9k helium. The development effort includes the assembly of a six inch model to verify required coil load is achieved. Status of the R&D effort and an update on the magnet design, including its incorporation into the design of a complete one meter long cold mass is presented.
RadiaBeam, Santa Monica, USA
BNL, Upton, Long Island, New York, USA
Advanced Design Consulting, Inc, Lansing, New York, USA
BNL, Upton, Long Island, New York, USA
National Synchrotron Light Source-II (NSLS-II) project is currently under construction. Procurement of various insertion devices (IDs) has begun. IDs in the project baseline scope include six 3.5m long damping wigglers (DWs) with 100mm period, two 2.0m Elliptically Polarizing Undulator (EPU) with 49mm period, two 3.0m-20mm period IVUs and one 1.5m-21mm IVU. Recently a special device for inelastic X-ray scattering beamline has been added to the collection of baseline devices. This is a special wide pole IVU with 22mm period for a long straight section. Three pole wigglers with 28mm gap and peak field over 1T will be utilized for NSLS bending magnet users. Examples of R&D work for future devices are: 1) Development of in-vacuum magnetic measurement system (IVMMS), 2) Use of new type of magnet such as PrFeB for improved performance on cryo-permanent magnet undulator (CPMU), 3) Development of closed loop He gas refrigerator with a linear motor actuator, 4) Adaptive gap undulator (AGU) 5) Various field measurement technique improvement. Design features of the baseline devices, ID-Magnetic Measurement Facility and the future plans for NSLS-II ID activities are described.
ANL, Argonne, USA
Extruded aluminum vacuum chambers are commonly used in the storage rings of synchrotron facilities. For 18 years the APS has designed and fabricated vacuum chambers made from extruded aluminum for use with insertion devices at the APS and for use at other facilities including BESSY II, the Swiss Light Source (SLS), the Canadian Light Source (CLS), the TESLA Test Facility (TTF), and the European Synchrotron Radiation Facility (ESRF). Most recently extruded aluminum chambers were developed for LCLS with a 0.5-mm wall thickness along the entire 3.8-meter length. Surface roughness for the LCLS vacuum chamber interior was reduced, on average, to less than 300 nm through an abrasive flow polishing technique. Currently under development is an extruded aluminum chamber for the superconducting undulator at the APS. So far, 120 vacuum chambers have been produced with these methods. Results of the development, construction, and manufacturing of extruded aluminum vacuum chambers with small vertical apertures and thin walls are presented. The design, technological challenges, and positive and negative experiences are discussed.
ANL, Argonne, USA
The Advanced Photon Source is planning [*] to produce a short-pulse x-ray beam by way of rf deflecting cavities that locally impose a y'-t correlation on the stored beam at an insertion device. SPring-8 recently proposed [**] a variation on this scheme whereby the deflecting cavities impose a local y-t correlation on the stored beam. In one case the chirp is in the angle coordinate and in the other case the position coordinate. They both use slits to pass through a "short" portion of the photon beam. The practical limitations for the two schemes are discussed and compared, such as photon source size and angular divergence, storage ring apertures, and slit transmission.
* A. Nassiri et al., these proceedings
** T. Fujita et al., Proc. of IPAC10, p. 39
BNL, Upton, New York, USA
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of maintaining three long straights with large horizontal beta function while providing the other 12 long straights with smaller horizontal beta function to optimize the brightness of insertion devices. Our study considers the possible linear lattice solutions as well as characterizing the nonlinear dynamics. Results are reported on optimizations of dynamic aperture required for good injection efficiency and adequate Touschek lifetime.
BNL, Upton, New York, USA
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of installing additional quadrupoles at the center of selected long straight sections in order to provide two low-beta source locations for undulators. The required modification to the linear lattice is discussed as well as the preservation of adequate dynamic aperture required for good injection efficiency and adequate Touschek lifetime.
BNL, Upton, Long Island, New York, USA
Both In-Vacuum Undulators (IVU) and Cryogenic Permanent Magnet Undulators (CPMU), each important to third generation light sources, are best characterized in their operating environment. To create a precise Hall probe map of an IVU/CPMU (IVU hereafter), an In-Vacuum Magnetic Measurement (IVMM) System is proposed. Point-by-point measurement of field and trajectory error at operating conditions informs corrective tuning. A novel design concept for a universal IVMM System has been developed and explored. The IVMM seals to the rectangular UHV-flange of the IVU and shares its common vacuum space. Moreover, a modular design permits a range of IVU of varying magnetic length to be mapped with a single IVMM System, and is thus cost effective when multiple IVU of different configuration are planned. Here we review aspects of the modular IVMM design concept.