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Swap-out injection to the Advanced Photon Source Upgrade storage ring necessitates the injection of ~17 nC electron bunches at 6 GeV. To aid with machine tune-up and to measure the beam size, diagnostic imaging screens are envisaged at several locations in the beam transport line from the booster synchrotron to the storage ring. As such, it is important to determine whether the response of these screens to charge is linear. In the present work, we examine the effect of sublinear intensity quenching of a Cerium-doped Yttrium-Aluminium-Garnet scintillator screen. A 1.3 megapixel FLIR BlackFly monochrome digital camera was used to image the beam at the scintillator. At 7 GeV beam energy, over the charge densities investigated (10 fC um⁻²), an approximately 10 % reduction of the imaging intensity due to quenching of the scintillator was observed., Proceedings of the 5th North American Particle Accelerator Conference, NAPAC2022, Albuquerque, NM, USA

The Linac Extension Area at the Advanced Photon Source is a flexible beamline area for testing accelerator components and techniques. Driven by the Advanced Photon Source electron linac equipped with a photocathode RF electron gun, the Linac Extension Area houses a 12 m long beamline. The beamline is furnished with YAG screens, BPMs and a magnetic spectrometer to assist with characterization of beam emittance and energy spread. A 1.4 m long insertion in the middle of the beamline is provided for the installation of a device under test. The beamline is expected to be available soon for testing accelerator components and techniques using round and flat electron beams over an energy range 150-450 MeV. In the present work, we describe this beamline and summarise the main beam parameters., Proceedings of the 5th North American Particle Accelerator Conference, NAPAC2022, Albuquerque, NM, USA

A bunch duration monitor (BDM) was installed at the end of a synchrotron light monitor (SLM) port in the Advanced Photon Source (APS) booster synchrotron. The BDM is based on a fast Hamamatsu metal-semiconductor-metal detector with nominal rise and fall times of 30 ps. Bunch length data is especially important as the bunch charge will be raised from 3 nC, used in the existing machine, to as much as 18 nC for APS-Upgrade operation. During preliminary high-charge studies, the SLM image is observed to move over a period of minutes while the BDM signal intensity varies; the motion is likely due to thermal loading of the in-tunnel synchrotron light mirror. Work is underway to stabilize the position using a simple feedback system and motorized mirror mount, as well as a new synchrotron light mirror assembly with improved thermal load handling. The feedback system will maintain optical alignment on the BDM at an optimum position based on the SLM centroid location. The optical layout and feedback system will be presented along with preliminary bunch length data., Proceedings of the 5th North American Particle Accelerator Conference, NAPAC2022, Albuquerque, NM, USA

We propose a novel beam loss detection scheme whereby activation of deionised cooling water is used to observe elevated radiation around the APS storage ring. This is based on radioactivation of oxygen within deionised cooling water by gamma rays above 10 MeV and neutrons above 15 MeV. Losses would be detected using a gamma ray detector monitoring process water flow out of the accelerator enclosure. We anticipate that this could be used to provide a segmented, distributed loss monitor system covering the accelerator components closest to locations where radiation is generated., Proceedings of the 5th North American Particle Accelerator Conference, NAPAC2022, Albuquerque, NM, USA

Electron beam microbunching instabilities can present operational limits on the practical operation of storage ring accelerators. In the present work, we outline components of a synchrotron radiation diagnostic beamline for the Advanced Photon Source Particle Accumulator Ring operating at frequencies up to approximately 1 THz., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

A beam size monitor provides an intuitive display of the status of the beam profile and motion in an accelerator. In the present work, we outline the design of the X-ray electron beam size monitor for the Advanced Photon Source Upgrade. Components and anticipated performance characteristics of the beam size monitor are outlined., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

One of the advantages of relativistic electron beams with microbunching at UV to visible wavelengths is the potential to generate coherent optical transition radiation (COTR) at a metal foil for diagnostics purposes. A significant microbunching fraction of at least 10% is expected for the case of a seed laser at 257.5 nm copropagating with a 343-MeV electron beam through a modulator undulator (3.2 cm period) at the Linac Extension Area (LEA) at Argonne National Laboratory. Diagnostic plans have been made for the COTR based-characterization of the microbunched beam size (~100 microns), divergence (sub-mrad), microbunching fraction, spectrum, and bunch length (sub-ps), as well as coalignment of the laser pulse and electron beam as previously described**. For that case, COTR enhancements over OTR of more than seven million were calculated, and we expect a similar enhancement of coherent optical diffraction radiation (CODR). Thus, we propose the modification of the microbunching diagnostics station to support initial (CODR) experiments with beam transit through an aperture in a metal screen or near a metal edge at the second screen position of the interferometer. We would explore whether the coherence function for CODR provides a complementary beam size monitor and whether COTR and CODR interferences from the two interferometer screens provide divergence and pointing information., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

With swap-out injection and a third-harmonic bunch lengthening cavity, time domain diagnostics will be beneficial tools in for optimisation of the Advanced Photon Source Upgrade electron storage ring. In the present work, we present plans for time-domain X-ray and visible photon diagnostics for the Advanced Photon Source Upgrade. Particular emphasis is given to implementation of visible light streak cameras and X-ray bunch purity monitors as time domain photon diagnostics., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

The Advanced Photon Source Upgrade (APS-U) is a high-performance fourth-generation storage ring light source based on multibend achromat optics. As such, APS-U will require on-axis injection. The injectors will need to supply full-current bunch replacement in the ring; therefore, the injected bunch charge will be up to five times higher than what is typical for APS. A program was conducted to measure the radiation dose above the injector transport line to the APS storage ring for both normal operation conditions and controlled loss scenarios. Standard survey meters were used to record the dose. A review of the dose data identified opportunities to minimize the potential dose under normal APS-U high charge operation and fault conditions; these include improving the supplemental shielding and adding engineered controls. In addition, the dose data provide a benchmark for evaluating new radiation monitors for APS-U., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

For the APS-Upgrade, swap-out injection will require the booster to support up to 17 nC bunch charge, several times what is used in the present APS. Booster injection efficiency drops sharply at high charge, and is the present bottleneck limiting high charge transport through the injectors. Particle tracking simulations have been used to understand what causes are limiting the injection efficiency, and to guide plans for improving it. In particular, bunch length blowup in the injected beam and beam loading in the RF cavities have been identified as the biggest factors. Simulations and measurements have also been done to characterize beam properties along the booster energy ramp. So far, a bunch charge of 12 nC has been successfully extracted from the booster., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The initial observations of optical synchrotron radiation (OSR) emitted over millions of passes from a few electrons circulating in the Particle Accumulator Ring (PAR) at the Advanced Photon Source have been done with a digital CMOS camera and a synchroscan streak camera operating at 117.3 MHz. The discrete changes of integrated counts in the CMOS image region of interest are ascribed to single electron steps at ~3500 cts per electron. Circulations of a single electron at 375 MeV and at 425 MeV were demonstrated in the 12-bit digital FLIR USB3 camera images. The Hamamatsu C5680 streak camera operating at the 12th harmonic of the fundamental revolution frequency at 9.77 MHz was used to measure the zero-current bunch length from 0.5 nC circulating charge down to 10s of electrons or 10 aC. The latter cases were performed with 6-ps temporal resolution for the first time anywhere, to our knowledge. We report a preliminary effective bunch length of 276 ± 36 ps for 57 electrons (9.1 aC) stored based on a fit to a single Gaussian peak. The results will be compared to the standard zero-current model for the ring., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

Relativistic electron beams in storage rings radiate a significant fraction of beam energy per turn. As demonstrated in previous experiments, with the radiofrequency accelerating structures off, the turn-by-turn time of arrival of the electron bunch can be observed from the synchrotron radiation that it produces using a streak camera. In the present work, we present measurements of the energy loss per turn of an initially short electron bunch (~1 ps RMS) from a photocathode electron gun in the Advanced Photon Source Particle Accumulator Ring (375 MeV, 10² ns revolution period). With the streak camera synchroscan locked to the twelfth harmonic of the revolution frequency (117.3 MHz), we observe an injection transient in the horizontal direction., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

The Advanced Photon Source (APS) is building a fourth-generation storage ring (4GSR), replacing the present double-bend achromat lattice with a multibend achromat system thereby allowing the production of ultra-bright x-ray beams. The new lattice enables a two-order-of-magnitude reduction in horizontal beam emittance and a factor of two increase in beam current. The result is an electron beam of very high energy- and power-densities. Initial predictions suggest virtually any material struck by the undiluted electron beam will be damaged. Two experimental beam abort studies have been conducted on collimator test pieces in the present APS SR to inform the design of a fully-functional machine protection system for APS 4GSR operations at 200 mA. A comprehensive suite of diagnostics were employed during the studies The diagnostics used in these experiments are not new, but employed in different ways to obtain unique data sets. With these data sets now in hand, we are developing new numerical tools to guide collimator design., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

To best leverage the orders of magnitude average brightness increase of multi-bend achromat synchrotron radiation storage rings, ambitious beam stability requirements are imposed. One system that will be employed at the Advanced Photon Source Upgrade in support of photon beam stability will be X-ray beam position monitors. In the present work, electrical characterisation of several types of photodiodes are evaluated for potential use in X-ray beam position monitors., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

Confirmation of pm rad scale emittances from the Advanced Photon Source Upgrade electron storage ring necessitates direct measurement of the electron beam size. In the present work, we motivate design choices for the X-ray beam size monitor shielding enclosure for the Advanced Photon Source Upgrade. Particular emphasis is given to outlining design choices from the perspectives of safety, overall project construction schedule and eventual beamline operations., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

The Advanced Photon Source (APS) particle accumulator ring (PAR) was designed to accumulate linac pulses into a single bunch with a fundamental rf system, and longitudinally compress the beam with a harmonic rf system prior to injection into the booster. For APS Upgrade, the injectors will need to supply full-current bunch replacement with high single-bunch charge for swap-out in the new storage ring. Significant bunch lengthening, energy spread, and synchrotron sidebands are observed in PAR at high charge. Lower-charge dynamics are dominated by potential well distortion, while higher-charge dynamics appear to be dominated by microwave instability. Before a numerical impedance model was available, a simple circuit model was developed by fitting the measured bunch distributions to the Haissinski equation. Energy scaling was then used to predict the beam energy sufficient to raise the instability threshold to 18-20 nC. With the beam in a linear or nearly linear regime, higher harmonic radio frequency (rf) gap voltage can be used to reduce the bunch length at high charge and better match the booster acceptance., Proceedings of the North American Particle Accelerator Conference, NAPAC2019, Lansing, MI, USA

Characterizations continue of the electron beam properties of a recently installed S-band photocathode (PC) rf gun at the Advanced Photon Source Linac facility. In this case, we have utilized a low-energy spectrometer beam line located 1.3 m downstream of the gun cavity to measure the electron beam energy, energy spread, and energy jitter. The nominal energy was 6.5 MeV using a gun gradient of 110 MV/m, and the energy spread was ~17 keV when driven by a 2.5-ps rms duration UV laser pulse at the selected rf gun phase. An energy jitter of 25 keV was initially observed in the spectrometer focal plane images. This jitter was partly attributed to the presence of both the 2nd and 3rd harmonics of the 119 MHz synchronization signal provided to the phase locked loop of the drive laser oscillator. The addition of a 150-MHz low-pass filter in the 119-MHz line strongly attenuated the two harmonics and resulted in a reduced energy jitter of ~15 keV. Comparisons of the gun performance to ASTRA simulations will also be presented., Proceedings of the North American Particle Accelerator Conference, NAPAC2019, Lansing, MI, USA

Cameras can be a very useful accelerator diagnostic, particularly because an image of the beam distribution can be quickly interpreted by human operators, and increasingly can serve as an input to machine learning algorithms. We present an implementation of digital cameras for triggered photon diagnostics at the Advanced Photon Source using the areaDetector framework in the Experimental Physics and Industrial Controls System. Beam size measurements from the synchrotron light monitors in the Particle Accumulator Ring using the new architecture are presented., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

A design choice for the Advanced Photon Source Upgrade to inject into the storage ring using bunch swap out rather than off-axis accumulation means that the Advanced Photon Source injectors are required to accelerate much higher electron bunch charge than originally designed. In the present work, we outline upgrades to the current monitor and beam position monitor diagnostics for the Particle Accumulator Ring to accommodate bunch charges of 1-20 nC. Through experiments, we compare and characterize the system responses over the range of bunch charge., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

One of the challenges of the injector for the Advanced Photon Source Upgrade (APS-U) is the measurement and monitoring of the required high charge electron beam at 6 GeV between the Booster synchrotron and the storage ring in the transport line (BTS. In APS-U charges of up to 17 nC per micropulse are specified with a beam geometrical horizontal emittance of 60 nm rad. Vertical beam sizes at the imaging station of ~80 µm (σ) are expected so system resolutions of 30 µm are warranted. A phased approach to enhance the imaging station performance has been initiated. Recently, the 20-year-old Chromox screen oriented at 45 degrees to the beam was replaced by a 100-micron thick YAG:Ce screen which gave an improved screen resolution of 10 micron(σ. However, the optical magnification of the system still needs to be increased. In addition, the high areal charge densities are expected to exceed the scintillator mechanism’s saturation threshold so an optical transition radiation (OTR) screen will be added to the station for high-charge studies. A final phase would be the use of optical diffraction radiation (ODR) as a non-intercepting, beam-size monitor during top-up injections., Proceedings of the North American Particle Accelerator Conference, NAPAC2019, Lansing, MI, USA

A particular challenge for diagnostics in diffraction limited storage ring light sources is the measurement of electron beam transverse emittances. In the present work, we present measurements and simulations of vertical electron beam emittance using high harmonics from an electromagnetic undulator in the present Advanced Photon Source storage ring. Based on these results, using simulation we motivate an undulator-based horizontal and vertical transverse emittance monitor for diffraction limited storage rings, using the Advanced Photon Source Upgrade as an example., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

We present the results of experiments intended to show the effects of beam dumps on candidate collimator materials for the Advanced Photon Source Upgrade (APS-U) storage ring (SR). Due to small transverse electron beam sizes, whole beam loss events are expected to yield dose levels in excess of 10 MGy in beam-facing components, pushing irradiated regions into a hydrodynamic regime. Whole beam aborts have characteristic time scales ranging from 100s of ps to 10s of microseconds which are either much shorter than or roughly equal to thermal diffusion times. Aluminum and titanium alloy test pieces are each exposed to a series of beam aborts of varying fill pattern and charge. Simulations suggest the high energy/power densities are likely to lead to phase transitions and damage in any material initially encountered by the beam. We describe measurements used to characterize the beam aborts and compare the results with those from the static particle-matter interaction code, MARS; we also plan to explore wakefield effects. Beam dynamics modeling, done with elegant is discussed in a companion paper at this conference. The goal of this work is to guide the design of APS-U SR collimators., Proceedings of the North American Particle Accelerator Conference, NAPAC2019, Lansing, MI, USA

Next-generation, high-performance storage ring light sources based on multibend achromat optics will require on-axis injection because of the extremely small dynamic aperture. Injectors will need to supply full-current bunch replacement in the ring with high single-bunch charge for swap-out. For upgrades of existing light sources, such as the Advanced Photon Source Upgrade (APS-U), it is economical to retain the existing injector infrastructure and make appropriate improvements. The challenges to these improvements include achieving high single-bunch charge in the presence of instabilities, beam loading, charge stability and reliability. In this paper, we discuss the rationale for the injector upgrades chosen for APS-U, as well as backup and potential alternate schemes. To date, we have achieved single-bunch charge from the injectors that doubles the original design value, and have a goal to achieve about three times the original design value., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

In order to maximise the injection efficiency from the booster synchrotron into the proposed Advanced Photon Source Upgrade storage ring, beam-based optimisation of the booster electron optical lattice is anticipated. In the present work, we present non-destructive beam size and emittance measurements using the booster synchrotron light monitor and destructive quadrupole scan emittance measurements in the booster to storage ring transport line. Destructive measurements are performed with a 0.1 mm thickness Cerium-doped Yttrium Aluminium Garnet screen. In order to characterise performance, both the beam energy at extraction (5, 6 and 7 GeV) and the bunch charge are varied., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

We present results of recent studies of new materials designed for the additive manufacturing of accelerating structures for dielectric laser accelerators (DLAs). Demonstration of a stand-alone practical DLA requires innovation in design and fabrication of efficient laser accelerator structures and couplers. Many complicated three-dimensional structures for laser acceleration (such as a long woodpile structure with couplers) are difficult to manufacture with conventional microfabrication technologies. LANL has a large effort focused on developing new materials and techniques for additive manufacturing. The materials for DLA structures must have high dielectric constant (larger than 4), low loss in the infrared regime, high laser damage threshold, and be able to withstand the electron beam damage. This presentation will discuss the development of novel infrared dielectric materials that are of interest for laser acceleration and are compatible with additive manufacturing, as well as recent advances in additive manufacturing of dielectric woodpile structures using a Nanoscribe direct laser-writing 3D printer., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

8th International Particle Accelerator Conference, IPAC 2017, Copenhagen, Denmark, 14 May 2017 - 19 May 2017 ; 2520-2525(2017). doi:10.18429/JACoW-IPAC2017-WEYB1, Dielectric laser acceleration of electrons has recently been demonstrated with significantly higher accelerating gradients than other structure-based linear accelerators. Towards the development of an integrated 1 MeV electron accelerator based on dielectric laser accelerator technologies, development in several relevant technologies is needed. In this work, recent developments on electron sources, bunching, accelerating, focussing, deflecting and laser coupling structures are reported. With an eye to the near future, components required for a 1 MeV kinetic energy tabletop accelerator producing sub-femtosecond electron bunches are outlined., Published by JACoW, Geneva, Switzerland

In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances*. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed., Proceedings of the 4th International Beam Instrumentation Conference, IBIC2015, Melbourne, Australia

We demonstrate experimentally that damage threshold fluence (DTF) for fused silica changes with the number of femtosecond laser (10Hz 600Hz, 655 fs, 800nm) shots. Based on the experimental data we were able to develop a model which indicates that the change in DTF varies with number of shots logarithmically (ln^{p}) up to a critical value. Above this value, DTF approaches an asymptotic value. Both DTF for a single shot and the asymptotic value as well as the critical value where this happens are extrinsic parameters dependent on the configuration (repetition rate, pressure and geometry near or at the surface). Indications are that the power of this dependence (p) is an intrinsic parameter independent of the configuration., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Recent experimental demonstrations of dielectric laser-driven accelerator structures offer a path to the miniaturisation of accelerators. In order to accelerate particles to higher energies using a staged sequence of accelerating structures, integrating compatible micrometre-scale transverse deflecting structures into these accelerators is necessary. Using simulations, the present work outlines the design and optimisation of a fused-silica laser-driven grating deflecting structure for relativistic electron beams. Implications for device fabrication and experiments are outlined., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

Using optical electromagnetic fields in dielectric microstructures, we can realize higher-energy accelerator systems in a more compact, low-cost form than the current state-of-the-art. Dielectric, laser-driven accelerators (DLA) have recently been demonstrated using fused silica structures to achieve about an order-of-magnitude increase in accelerating gradient over conventional RF structures.* We leverage higher damage thresholds of silicon over metals and extensive micromachining capability to fabricate structures capable of electron acceleration. Our monolithic structure, the buried grating, consists of a grating formed on either side of a long channel via a deep reactive ion etch (DRIE).** The grating imposes a phase profile on an incoming laser pulse such that an electron experiences a net change in energy over the course of each optical cycle. This results in acceleration (or deceleration) as electrons travel down the channel. We have designed and fabricated such structures and begun testing at the SLAC National Accelerator Laboratory. We report on the progress toward demonstration of acceleration in these structures driven at 2um wavelength., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

The X-band FEL collaboration is currently designing an X-ray free-electron laser based on X-band acceleration technology. Due to the higher accelerating gradients achievable with X-band technology, a X-band normal conducting linac can be shorter and therefore potentially cost efficient than what is achievable with lower frequency structures. This cost reduction of future FEL facilities addresses the growing demand of the user community for coherent X-rays. The X-band FEL collaboration consists of 12 institutes and universities that jointly work on the preparation of design reports for the specific FEL projects. In this paper, we report on the on-going activities, the basic parameter choice, and the integrated simulation results. We also outline the interest of the X-band FEL collaboration to use the electron linac CALIFES at CERN to test FEL concepts and technologies relevant for the X-band FEL collaboration., Proceedings of the 37th International Free Electron Laser Conference, FEL2015, Daejeon, Republic of Korea

Silicon woodpile photonic crystals provide a base structure that can be used to build a three-dimensional dielectric waveguide system for high-gradient laser-driven acceleration. A new woodpile waveguide design that hosts a phase synchronous, centrally confined accelerating mode with ideal Gaussian transverse profile is proposed. Comparing with previously discovered silicon woodpile accelerating modes, this mode shows advantages in better beam loading and higher achievable acceleration gradient. Several travelling-wave coupler design schemes developed for multi-cell RF cavity accelerators are adapted to the woodpile accelerator coupler design based on this new accelerating mode. A forward-wave-coupled, highly efficient silicon woodpile accelerator is achieved. Simulation shows high efficiency of over 70% of the drive laser power coupled to this fundamental woodpile accelerating mode, with less than 15% backward wave excitation. The estimated acceleration gradient, when the coupler structure is driven at the damage threshold fluence of silicon at its operating 1.506 um wavelength, can reach roughly 185 MV/m., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

Further reduction of betatron coupling and vertical dispersion in the storage ring of the Australian Synchrotron Light Source has resulted in the achievement of a beam vertical emittance that is now dominated by the intrinsic quantum effects. This paper will detail the key elements in achieving a vertical emittance at the quantum limit and results achieved., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

As is widely recognized, fourth generation Light Sources are based on FELs driven by Linacs. Soft and hard X-ray FEL facilities are presently operational at several laboratories, SLAC (LCLS), Spring-8 (SACLA), Elettra-Sincrotrone Trieste (FERMI), DESY (FLASH), or are in the construction phase, PSI (SwissFEL), PAL (PAL-XFEL), DESY (European X-FEL), SLAC (LCLS II), or are newly proposed in many laboratories. Most of the above mentioned facilities use NC S-band (3 GHz) or C-band (6 GHz) linacs for generating a multi-GeV low emittance beam. The use of the C-band increases the linac operating gradients, with an overall reduction of the machine length and cost. These advantages, however, can be further enhanced by using X-band (12 GHz) linacs that operate with gradients twice that given by C-band technology. With the low bunch charge option, currently considered for future X-ray FELs, X-band technology offers a low cost and compact solution for generating multi-GeV, low emittance bunches. The paper reports the ongoing activities in the framework of a collaboration among several laboratories for the development and validation of X-band technology for FEL based photon sources.

This paper summarizes the physics potential of the CLIC high-energy e+e- linear collider. It provides input to the Snowmass 2013 process for the energy-frontier working groups on The Higgs Boson (HE1), Precision Study of Electroweak Interactions (HE2), Fully Understanding the Top Quark (HE3), as well as The Path Beyond the Standard Model -- New Particles, Forces, and Dimensions (HE4). It is accompanied by a paper describing the CLIC accelerator study, submitted to the Frontier Capabilities group of the Snowmass process.

A new arrangement for the synchrotron radiation interferometer was proposed - as far as is known, it is unique in the world. The Young’s-type interferometer is composed of two independent and optically identical paths, each with a single slit on a motorised translating stage. These two single slit patterns are interfered to produce a double slit diffraction pattern. This arrangement permits rapid scanning of the profile of fringe visibility as a function of slit separation. The interferometer was used on two beamlines at the Australian Synchrotron, the optical diagnostic and infrared beamlines. The interferometer was used to measure the coherence of the photon beam created by the electron beam source, for normal and low emittance couplings. A large change in fringe visibility was observed, proving the experimental arrangement. The interferometer was validated in the measurement of the width of a hard-edged single slit, akin to Thompson and Wolf’s diffractometer. Optical simulations and measurements inform proposed modifications to the optical diagnostic beamline, so as to implement the interferometer as a regular diagnostic tool., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

Preliminary plans are presented for a sub-Angstrom wavelength XFEL at the Australian Synchrotron light source site. The design is based around a 6 GeV x-band linac from the CLIC Project. One of the motivations for the design is to have an XFEL co-located on the site with existing storage ring based synchrotron light source. The desire and ability of the Australian photon science community to win beamtime on existing XFELs has lead to this design study to plan for a future machine in Australia. The technology choice is also driven by the Australian participation in the CLIC Collaboration and the local HEP community., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany