A distributed beam loss monitoring system, named the optical fibre Beam Loss Monitor, has been installed at the Australian Synchrotron. Relativistic charged particles produced in beam loss events generate photons via the Cherenkov mechanism in four silica fibres that run parallel to the beam pipe and cover the majority of the accelerator's length. These photons are then guided by the fibres to detectors located outside of the accelerator tunnel. By measuring the time of flight of these photons, the locations of beam losses can be reconstructed. Based on this method a calibration was produced, mapping the time of flight to a position along the accelerator. This calibration was applied to loss signals collected on the first pass of the beam through the accelerator and the locations of prominent losses were determined. Using this system it was possible to investigate the effect, on the location and intensity of losses, in response to changes in the lattice parameters on a shot-by-shot basis. This system is now used in routine operations and has resulted in a 40 % increase in the capture efficiency of the booster ring.

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.

The Australian Synchrotron Light Source has been operating successfully since 2007 and in top-up mode since 2012, while additionally being gradually upgraded to reach a beam availability exceeding 99 %. Considering the ageing of the equipment, effort is required in order to maintain the reliability at this level. The proposed upgrade of the linac with a SLED cavity has been chosen to mitigate the risks of single point of failure and lack of spare parts. The linac is normally fed from two independent klystrons to reach 100 MeV beam energy, and can be operated in single (SBM) or multi-bunch mode (MBM). The SLED cavity upgrade will allow remote selection of single klystron operation in SBM and possibly limited MBM without degradation of beam energy and reduce down time in case of a klystron failure. The proposal for the SLED cavity upgrade is shown and the linac designs are detailed. INTRODUCTION The injector comprises a 100 MeV linac and a 3 GeV booster to enable full energy beam injection into the storage ring. The injector was upgraded later from decay to top-up mode operation to keep the storage ring at 200 mA current. Top-up has been continually running since then with an MBM injection of 0.5 mA every few minutes compared to a reinjection every 12 hours in decay mode. Alongside top-up came the need to improve reliability and mean down time for the entire facility. Improvements on the injector were more cost effective to target mean down time due to the increase in wear on the system, single point of failure and the limited lifespan of devices such as the electron tubes. Improvements on the linac were necessary with two klystrons required for operation, and a failure could take weeks, depending on missing critical spare parts. The waveguide radio frequency (RF) distribution system for the linac was modified in the first stage in 2010, to test single klystron operation to power the whole linac; albeit at a reduced final beam energy. Booster injection was successful, but booster ramping remained unsolved as a lack of control in fine field adjustments at low energy levels from below 100 MeV. The increase in klystron trips operating at higher power levels was also not satisfactory. The next stage is to add a SLED cavity to overcome the current deficiencies. This paper will outline the proposed upgrade and benefits. LINAC OVERVIEW General Specifications The 100 MeV 3 GHz linac structure is made of a 90 keV thermionic electron gun (GUN), a 500 MHz subharmonic prebuncher unit (SPB), preliminimary buncher (PBU), final buncher (FBU), and two 5 m accelerating structures. The structures are powered by two 35 MW pulsed klystrons supplied from a pulse forming network (PFN). The low level electronics include two pulsed 400W S band amplifiers to drive the klystrons, and two 500W UHF amplifiers for the GUN and SPB. The linac is based on the SLS/DLS design and was delivered by Research Instruments, formerly ACCEL, the modulators subcontracted to PPT-Ampegon, and the waveguide to SPINNER. The linac overview is shown in Figure 1, a summary of the general specifications listed in Table 1 and more details referenced to [1]. KLYSTRON 1 POS: 00000

This paper presents measurements of the GeV-scale electron beam energy for the storage rings at the synchrotron light source facilities Australian Synchrotron (AS) and SPEAR3 at SLAC. Resonant spin depolarization was employed in the beam energy measurement, since it is presently the highest precision technique and an uncertainty of order 10(-6) was achieved at SPEAR3 and AS. Using the resonant depolarization technique, the beam energy was measured at various rf frequencies to measure the linear momentum compaction factor. This measured linear momentum compaction factor was used to evaluate models of the beam trajectory through combined-function bending magnets. The main bending magnets of both lattices are rectangular, horizontally defocusing gradient bending magnets. Four modeling approaches are compared for the beam trajectory through the bending magnet: a circular trajectory, linear and nonlinear hyperbolic cosine trajectories, and numerical evaluation of the trajectory through the measured magnetic field map. Within the uncertainty of the measurement the momentum compaction factor is shown to agree with the numerical model of the trajectory within the bending magnet, and disagree with the hyperbolic cosine approximation.

The Australian Synchrotron introduced Top-Up operations in May 2012. Upgrading the machine for Top-Up has required major developments in many of the accelerator systems. Investigations prior to the start of Top-Up operations demonstrated that the Infrared Microspectroscopy beamline was particularly sensitive to injection noise. A gating event has been implemented as part of our timing system upgrade to pause the data collection during injection. In Top-Up mode injections can happen when the gaps of insertion devices are closed. A variable vertical aperture has been installed in the BTS to scape potentially damaging electrons and protect the equipmen.

The CLIC Detector and Physics Study H. Abramowicz1, A. Abusleme2, K. Afanaciev3, G. Alexander1, N. Alipour Tehrani4, O. Alonso5,6, K.K. Andersen7, S. Arfaoui4, C. Balazs8,9, T. Barklow10, M. Battaglia11, M. Benoit4, B. Bilki12, J.-J. Blaising13, M. Boland8,14, M. Boronat5,15, I. Božović Jelisavčić16, P. Burrows17, M. Chefdeville13, R. Contino18, D. Dannheim4, M. Demarteau12, M.A. Diaz Gutierrez2, A. Diéguez5,6, J. Duarte Campderros5,19, G. Eigen20, K. Elsener4, D. Feldman21, U. Felzmann8,14, M. Firlej22, E. Firu23,

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.

This paper reports the use of neural networks for orbit correction at the Australian Synchrotron Storage Ring. The proposed system uses two neural networks in an actor-critic scheme to model a long term cost function and compute appropriate corrections. The system is entirely based on the history of the beam position and the actuators, i.e. the corrector magnets, in the storage ring. This makes the system auto-tuneable, which has the advantage of avoiding the measure of a response matrix. The controller will automatically maintain an updated BPM corrector response matrix. In future if coupled with some form of orbit response analysis, the system will have the potential to track drifts or changes to the lattice functions in ”real time”. As a generic and robust orbit correction program it can be used during commissioning and in slow orbit feedback. In this study, we present positive initial results of the simulations of the storage ring in Matlab.

We report on the development of a neural network based optimisation agent for the real-time optimisation of electron beam parameters at the Australian Synchrotron Linac. The system mimics an operator's decisions to perform an optimisation task when no prior knowledge, other than constraints on the actuators, is available. In this paper we show simulation results in a 3D search space, and give results for the real-time optimisation of the beam transmission 1 and energy spread 2 . The agent is designed to handle any number of parameters and in this study the optimisation was performed by adjusting sets of 2, 4 and 7 focusing magnets at a time. Our experimental results demonstrate very satisfactory performance, with a successful increase in transmission from 65% to 70%, in combination with a decrease in the energy spread from 1.26% to 0.80%.

The Australian Synchrotron has been open to users since April 2007. Beam availability is now consistently above 98%, with a Mean Time Between Failures (MTBF) of approximately 50 hours and a Mean Down Time (MDT) of approximately 1 hour. This paper discusses the program of activities that has been undertaken to improve beam availability, and to maximize the MTBF and reduce the MDT. BACKGROUND One of the most important Key Performance Indicators (KPI) for the Australian Synchrotron, now into its 4 th year of operations, is beam availability greater than 97%. In striving to actively improve performance and reliability in many areas, it was realised that one of the major factors in maximising availability, is implementing preventative measures and recovery procedures after an unscheduled beam loss [2]. By successfully implementing improvements in these areas, we have already managed to achieve availability > 98%, which is above our long term target (see Fig. 1).

Time resolved experiments require precision timing equipment and careful configuration of the machine and the beamline. The Australian Synchrotron has a state of the art timing system that allows flexible, real-time control of the machine and beamline timing parameters to target specific electron bunches. Results from a proof-of-principle measurement with a pulsed laser and a streak camera on the optical diagnostic beamline will be presented. The timing system was also used to fast trigger the PILATUS detector on an x-ray beamline to measure the fill pattern dependent effects of the detector. PILATUS was able to coarsely measure the fill pattern in the storage ring which implies that fill pattern intensity variations need to be corrected for when using the detector in this mode.

This article describes the development, commissioning and operation of a Fill-Pattern Monitor (FPM) for the Australian Synchrotron that measures the real-time intensity distribution of the electron bunches in the storage ring. Using a combination of an ultra-fast photodiode and a high-speed digitiser, real-time measurement of the fill-pattern at bunch-by-bunch resolution was achieved. The results compare very well with current methods of measuring the fill-pattern, such as a pick-up style detector. In addition, the FPM is fully integrated into the EPICS control system. The data provided by the FPM gives accurate RF bucket position and relative bunch currents over a wide range of stored beam currents, from 0.01mA in a single bunch to 200mA total beam current. The FPM monitors the success of an injection attempt into the storage ring and is used in a feedback loop to determine where to target the next injection. Using the FPM a beam top-up mode was successfully tested, resulting in a near constant beam current by periodic targeted injections over an 8h shift. Results are presented for dynamically topped up real-time injection, where the beam pattern was squared using an intensity-dependent injection algorithm.

The Australian Synchrotron is now a fully commissioned synchrotron light source providing beam for users [1]. With the facility now fully operational, the next major advancement in machine operations will be top-up mode. The advantages of running in a dynamic top-up mode are well documented by other third generation light sources (see for examples references [2, 3, 4]) ; in broad terms it leads to a better quality beam for some users, and better experimental results. An overview will be given of the top-up runs that have been conducted and the instrumentation that was used. It has been demonstrated that top-up operation is possible, however improvements in injection efficiency and beam stability during injection are required before this can become a routine mode of operation.

The Australian synchrotron's Storage Ring is equipped with a full compliment of 98 Libera electron beam position processors from I-tech (EBPPs) [1]. The EBPPs are capable of measuring beam position data at turn-by-turn (TBT) rates and have long history buffers. TBT data from the EBPPs has been used to determine the linear optics of the storage ring lattice using techniques developed at other facilities. This is a useful complement to other methods of determining the linear optics such as LOCO. Characteristics of the EBPPs such as beam current dependence have been studied during commissioning and will also be presented.

Danfysik has delivered a full-energy turn-key injection system for the Australian Synchrotron. The system consists of a 100 MeV linac, a low-energy transfer beamline, a 130 m circumference 3-GeV booster, and a high energy transfer beamline. The booster lattice was designed to have many cells with combined-function magnets (dipole, quadrupole and sextupole fields) in order to reach a very small emittance. The injection system has been commissioned and shown to deliver a beam with an emittance of less than 30 nm, and currents in single- and multi-bunch mode in excess of 0.5 and 5 mA, respectively, fulfilling the performance specifications. The repetition frequency is 1 Hz. Results from the commissioning of the system will be presented.

This paper will give an overview of the Australian Synchrotron Project (ASP) storage ring and injection system [1]. The ASP storage ring is a 3 GeV machine with 14 identical cells and a circumference of 216 m. The unit cell is based on a Double Bend Achromat (DBA) structure. The present design of the magnet lattice and the results of simulations pertaining to the storage ring performance are presented. The facility is expected to be in operation by March 2007 [2].

This article describes the development, commissioning and operation of a Fill-Pattern Monitor (FPM) for the Australian Synchrotron that measures the real-time intensity distribution of the electron bunches in the storage ring. Using a combination of an ultra- fast photo diode and a high-speed digitizer, real-time measurement of the fill-pattern at bunch-by-bunch resolution was achieved. The results compare very well with current methods of measuring the fill-pattern, such as a pick-up style detector. In addition, the FPM is fully integrated into the EPICS control system. The data provided by the FPM gives accurate RF bucket position and bunch current over a wide range of currents, from 0.01 mA in a single bunch to 200 mA total beam current. The FPM monitors the success of an injection attempt into the storage ring and is used on a feedback loop to determine where to target the next injection. Using the FPM a beam top-up mode was successfully tested, resulting in a near constant beam current by periodic targeted injections over an 8 hour shift. Results are presented for dynamically topped up real-time injection, where the beam pattern was squared using an intensity- dependent injection algorithm.

Studies using a single high charge electron bunch have been conducted at the Australian Synchrotron to charac- terise the impedance of the machine at various stages of commissioning and insertion device configuration. This paper will present the results of these studies and show the time evolutionof machineimpedancewith increasingnum- ber of insertion devices. OVERVIEW The Australian Synchrotron is a 3rd generation light source facility located in Melbourne, Australia. Commis- sioning was conducted in 2006, with beamline operations commencing in April 2007. The 3 GeV storage ring is 216 metres in circumference and can store a beam of up to 200 mA current. A design overview can be found in (1). The first phase of beamline development consists of 9 initial beamlines, 5 of which are currently in operation and the other 4 are in late stages of construction. Of these 9 beam- lines, 6 will use insertion devices (IDs), 3 being In-Vacuum Undulators (IVUs). Both kinds of insertion devices require specialised vacuum chambers and their inclusion has an ef- fect on the impedance of the storage ring. The single bunch studies presented in this paper were conducted at various times over the last year, as the storage ring became more and more populated with insertion devices.

The Australian Synchrotron upgraded its user mode from decay mode to top-up mode in May 2012. To monitor the beam charge passing through the accelerator systems at key transfer points the transmission efficiency system has been upgraded. The original system could only measure the efficiency of the booster to storage ring injection. The new one calculates intermediate efficiencies between six points along the injection system, from the electron gun to the booster-to-storage ring transfer line. This is helpful to diagnose in real-time shot-to-shot the performance of the pulsed magnets, ramped magnets and ramped RF systems and their associated triggers. A software-based injection efficiency interlock has also been introduced, that can inhibit the gun when the machine settings are not optimal. This article details the architecture of the injection efficiency system and lists the improvements on the machine that have been carried out to obtain high quality data.