Science needs are pushing the development of MHz-class repetition-rate linac-based facilities generating high-brightness electron beams. The successful lower repetition-rate RF gun schemes cannot be scaled up to MHz rates. At LBNL, we developed the VHF-Gun, a room-temperature RF gun designed for CW operation and high-brightness beam performance.

The APEX electron source at LBNL combines highrepetition-rate and high beam brightness typical of photoguns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity is being installed, and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.

The Advanced Photoinjector Experiment (APEX) at the Lawrence Berkeley National Laboratory is dedicated to the development of a high-brightness high-repetition rate (MHz-class) electron injector for x-ray free-electron laser (FEL) and other applications where high repetition rates and high brightness are simultaneously required. The injector is based on a new concept rf gun utilizing a normal-conducting (NC) cavity resonating in the VHF band at 186 MHz, and operating in continuous wave (cw) mode in conjunction with high quantum efficiency photocathodes capable of delivering the required charge at MHz repetition rates with available laser technology. The APEX activities are staged in three phases. In phase 0, the NC cw gun is built and tested to demonstrate the major milestones to validate the gun design and performance. Also, starting in phase 0 and continuing in phase I, different photocathodes are tested at the gun energy and at full repetition rate for validating candidate materials to operate in a high-repetition rate FEL. In phase II, a room-temperature pulsed linac is added for accelerating the beam at several tens of MeV to reduce space charge effects and allow the measurement of the brightness of the beam from the gun when integrated in an injector scheme. The installation of the phase 0 beam line and the commissioning of the VHF gun are completed, phase I components are under fabrication, and initial design and specification of components and layout for phase II are under way. This paper presents the phase 0 commissioning results with emphasis on the experimental milestones that have successfully demonstrated the APEX gun capability of operating at the required performance.

The APEX project aims to the construction of a high brightness high repetition rate photo-injector at LBNL. In its first phase a 750 keV electron bunch is produced at a maximum repetition rate of 1 MHz, with an adjustable charge per bunch spanning the pC-to-nC region. A load lock system is foreseen to test different cathodes without the need of breaking the vacuum and the downstream diagnostic is used to characterize the photo-emitted beam brightness. In the initial phase the main effort is directed toward the measurement of photocurrent, dark current, thermal emittance and electron beam kinetic energy. In a successive phase, diagnostic for full 6D phase space characterization of space charge dominated beams will be added to the beamline. We report and discuss the present diagnostic beamline layout, first beam measurements and future upgrades. OVERVIEW The APEX electron beam parameter space is summarized in Table 1. The project has been conceived as an R&D on MHz-class photo-injectors, particularly toward the possible application as driver for high repetition rate FELs [1]. A CW 187 MHz normal conducting rf-gun has been specifically designed and constructed for this purpose [2]. The low frequency and the peculiar design allow the power density on the walls to be within 25 W/cm 2 when running in CW at full power (100kW), and at the same time to sustain an adequate accelerating field (20 MV/m) at the cathode, a key parameter for high brightness beams generation. Furthermore, the low rf frequency allow to open big slots on the cavity walls without disturbing the field, that are used to increase the vacuum conductivity and make the system compatible with very high vacuum performances ( 10 �12 Torr) [2]. Such a system, together with a load lock system is therefore a perfect environment to testing highly reactive cathode materials, with high quantum efficiencies and limited lifetimes. As photocathode laser an Ytterbium-doped fiber laser system provides 700 nJ pulses at 1 MHz (0.7 W) at a wavelength of 1060 nm and pulse width of about 600 fs FWHM. Second and fourth harmonic are generated (respectively 250 and 80 nJ) and transported to the cathode, for different work function materials. Transverse and longitudinal pulse shaping allows for different electron beam densities and aspect ratios. The wide range of measurable beam parameters make

The APEX project at the Lawrence Berkeley National Laboratory is devoted to the development of a high repetition rate (MHz-class) electron injector for X-ray FEL applications. The injector is based on a new concept photo-gun, utilizing a normal conducting 186 MHz (VHF) RF cavity operating in CW mode in conjunction with high quantum efficiency photo-cathodes able to deliver the required repetition rates with available laser technology. The APEX activities are staged in phases. In Phases 0 and I, the electron photo-gun is constructed, tested and several different photo-cathodes, such as multialkali antimonides, cesium telluride [1], and diamond amplifiers [2], are tested at full repetition rate. In Phase II, a pulsed linac is added for accelerating the beam at several tens of MeV to prove the high brightness performance of the gun when integrated in an injector scheme. APEX is located in an existing area with a radiation shielding configuration limiting the repetition rate at Phase II energies down to several Hz. Based on funding availability, after Phase II the program could also include testing of new undulator technologies and FEL studies. The status of Phases 0 and I, in the initial experimental phase, is described together with plans and activities for Phase II and beyond.

A high-repetition rate (MHz-class), high-brightness electron beam photo-gun is under construction at Lawrence Berkeley National Laboratory in the framework of the Advanced Photo-injector EXperiment (APEX). The injector gun is based on a normal conducting 187 MHz RF cavity operating in CW mode. In its first operational phase it will deliver short bunches (∼1 to tens of picoseconds) with energy of 750 keV, and bunch charges ranging from 1 pC to 1 nC. Different high efficiency cathode materials will be tested, and the beam quality will be studied as a function of parameters as charge, initial bunch length and transverse size, focusing strength. Both the laser and electron beam diagnostics have been designed to assure the needed flexibility. In particular a high-resolution electron diagnostic section after the photo-gun provides the necessary dynamic range for scanned beam parameters: energy and energy spread, charge and current, transverse and longitudinal phase spaces, slice properties. The photo-gun electron beam diagnostic layout is presented, and the hardware choices, resolution and achievable dynamical ranges are also discussed.

GM/CA-CAT at Sector 23 of the Advanced Photon Source (APS) is an NIH funded facility for crystallographic structure determination of biological macromolecules by X-ray diffraction. A second-generation Berkeley automounter is being integrated into the beamline control system at the 23BM experimental station. This new device replaces the previous all-pneumatic gripper motions with a combination of pneumatics and XYZ motorized linear stages. The latter adds a higher degree of flexibility to the robot including auto-alignment capability, accommodation of a larger capacity sample Dewar of arbitrary shape, and support for advanced operations such as crystal washing, while preserving the overall simplicity and efficiency of the Berkeley automounter design.

The HEXAGONE balloon‐borne spectrometer has flown on 22 May 1989. HEXAGONE is a high resolution gamma‐ray spectrometer and consists of an array of twelve cooled germanium detectors. One of the observed targets was the Galactic Center and its vicinity (field of view 19° at 511 keV) and it was seen during 6.3 hours. The 511 keV annihilation line was observed with a flux of (8.88±2.67)×10−4 γcm−2 s−1, a width 1.09+1.38, −1.09 keV and its centroid at 511.54±0.38 keV. The results are consistent with an upper limit of 8.3×104 K for the temperature of the annihilation medium of the positrons.The HEXAGONE balloon‐borne spectrometer has flown on 22 May 1989. HEXAGONE is a high resolution gamma‐ray spectrometer and consists of an array of twelve cooled germanium detectors. One of the observed targets was the Galactic Center and its vicinity (field of view 19° at 511 keV) and it was seen during 6.3 hours. The 511 keV annihilation line was observed with a flux of (8.88±2.67)×10−4 γcm−2 s−1, a width 1.09+1.38, −1.09 keV and its centroid at 511.54±0.38 keV. The results are consistent with an upper limit of 8.3×104 K for the temperature of the annihilation medium of the positrons.

We report on the development of high-sensitivity and compact Compton imaging systems built of large and position-sensitive Si(Li) and HPGe detectors. The primary goal of this effort is to provide improved capabilities in the passive detection of nuclear materials for homeland security. Our detectors are implemented in double-sided strip configuration, which—along with digital signal processing—provides energies and three-dimensional position information of individual γ-ray interactions. γ-Ray tracking algorithms then determine the scattering sequence of the γ-ray, which in turn allows us—employing the Compton scattering formula—to reconstruct a cone of possible incident angles and ultimately an image. This Compton imaging concept enables large-field-of-view γ-ray imaging without the use of a heavy collimator or aperture. The intrinsically high-energy resolution of the detectors used, the excellent position resolution we have demonstrated, both combined with the high efficiency of large-volume detectors is the basis for high Compton imaging sensitivity. These capabilities are being developed to identify and localize potential threat sources and to potentially increase the sensitivity in detecting weak sources out of the midst of natural, medical, or commercial sources. γ-ray imaging provides a new degree of freedom to distinguish between spatial and temporal background fluctuations and compact threat sources.

As part of the annual Advanced Light Source (ALS) andStanford Synchrotron Radiation Laboratory (SSRL) Users' Meeting inOctober of this year, the macromolecular crystallography staff at bothsynchrotrons held a joint hands-on workshop to address automation issuesin crystal mounting and data collection at the beamline. This paperdescribes the ALS portion of the workshop, while the accompanying paperreviews the SSRL workshop.

Semiconductor foundries need to have a single, standard mask preparation procedure to deal with the large number of designs they receive. This data is typically of two sorts; the random logic over which they have little control of how the design intent is represented; and cells from dense arrays such as memory, often with design rule violations, whose OPC correction needs to be precisely optimized to achieve best yield and device performance. Occasionally the input data will contain sub-resolvable notches and extensions, which while not violating DRC specifications, would, if filled, result in DRC violations. This may be due to a non DFM aware automated layout tool, or a designer aggressively trying to minimize circuit density. In practice it is worthwhile to clean up these notches to ease OPC correction. Doing this should not result in printability errors as these notches typically represent a more complex curved design intent that cannot be accurately represented due to the restrictions imposed by the limited number of polygon edge directions available for layout. Similarly, memory cell layouts often have significant implied curvature. These may only be corrected properly if the OPC target point is defined precisely for each individual segment. In general, letting the OPC correction engine correct a layout defined by a realistic, curved target shape gives better quality corrections with greater process window. The challenge for the OPC engineer working in a foundry is therefore to determine a clean-up methodology for incoming data and to correctly apply the design intent, where necessary, from the original pre-cleanup data. A programmable OPC engine gives the user flexibility in optimizing the set of rules embedded in the OPC cleanup and correction recipes. These embed within them the algorithms to interpret the rounding on the desired silicon image not only for line-ends and corners of random logic but also the more complex curved silicon images and tolerances required by memory cells.

At the deep Subwavelength process nodes, the use of the aggressive optical proximity correction (OPC) and resolution enhancement techniques (RET) is fostering an exponential increase in output database size causing the CPU time required for mask tape-out to increase significantly. This sets up challenging scenarios for integrated device manufacturers (IDMs), and Foundries. For integrated device manufacturers (IDMs), this can impact the time-to-market for their products where even a few days delay could have a huge commercial impact and loss of market window opportunity. For foundries, a shorter turnaround time provides a competitive advantage in their demanding market, too slow could mean customers looking elsewhere for these services; while a fast turnaround may even command a higher price. With FAB turnaround for a CMOS process around 20-30 days, a delay of several days in mask tapeout would contribute a significant fraction to the total time to deliver prototypes. Unlike silicon processing, masks tape-out time can be decreased by applying a combination of extra computing resources and enhancements in the OPC tool like Fracture Friendly OPC (FFOPC) . Mask tape-out groups are taking advantage of the ever-decreasing hardware cost and increasing power of commodity processors. The significant distributability inherent in some commercial Mask Synthesis software can be leveraged to address this critical business issue. Different implementations have different fractions of the code that cannot be parallelized and this affects the efficiency with which it scales, as is described by Amdahl's law. Very few are efficient enough to allow the effective use of 100's of processors, enabling run times to drop from days to only minutes. What follows is a cost aware methodology to quantify the scalability of this class of software, and thus act as a guide to estimating the optimal investment in terms of hardware and software licenses.

Summary tem, where automated data processing and structure solving software can influence the data collection pro- High-throughput data collection for macromolecular cess (e.g., crystal ranking and data collection strategycrystallographyrequiresanautomatedsamplemount- determination). (iv) Due to the high efficiency of the ing and alignment system for cryo-protected crystals system, the experimenter can evaluate a large pool ofthat functions reliably when integrated into protein- samples and select the best crystal from the set. This crystallography beamlines at synchrotrons. Rapid enables collection of higher quality data. (v) Mountingmounting and dismounting of the samples increases and dismounting of crystals can be done reliably reduc- the efficiency of the crystal screening and data collec- ing risk to crystals due to manual handling. (vi) System-tion processes, where many crystals can be tested for aticstudies ofexperimentalprotocolscan beperformed the quality of diffraction. The sample-mounting sub- in a manner and amount that would be impractical forsystem has random access to 112 samples, stored

Author(s): Sauter, Nicholas K.; Cork, Carl W.; Grosse-Kunstleve, Ralf W.; Taylor, John R.; Earnest, Thomas N.; Adams, Paul D. | Abstract: Structural genomics programs and drug discovery efforts that investigate large sets of crystalline samples are placing increased demands on synchrotron beamlines. To facilitate high-throughput work, beamlines 5.0.1, 5.0.2, and 5.0.3 at the ALS have been equipped with robotic arms [Structure (2004) 12:537-545] to transfer cryocooled samples to the goniometer. High-level graphical controls allow the user to conduct experiments with minimal input, while much of the work is performed by underlying software modules. The AutoScreen module rapidly evaluates 96 samples, centering each cryoloop on the beam position by analyzing videomicrographs. Two diffraction snapshots are acquired for each crystal, and then the Lawrence Berkeley Indexing Toolbox (LABELIT) autoindexes the diffraction pattern and determines the Bravais symmetry. LABELIT implements new methods to treat three common failure modes experienced during indexing: 1) non-primitive basis, 2) incorrect beam center, and 3) faulty symmetry. Correcting these problems allows images to be indexed rapidly without the need for interactive visual inspection. An AutoCollect module is now under development to deduce and set the optimal data collection parameters, while an AutoProcess module will reduce the diffraction data in real time and determine the space group. We anticipate that these tools will increase experimental efficiency for both individual users and large-scale efforts alike.

High-throughput data collection for macromolecular crystallography requires an automated sample mounting and alignment system for cryo-protected crystals that functions reliably when integrated into protein-crystallography beamlines at synchrotrons. Rapid mounting and dismounting of the samples increases the efficiency of the crystal screening and data collection processes, where many crystals can be tested for the quality of diffraction. The sample-mounting subsystem has random access to 112 samples, stored under liquid nitrogen. Results of extensive tests regarding the performance and reliability of the system are presented. To further increase throughput, we have also developed a sample transport/storage system based on "puck-shaped" cassettes, which can hold sixteen samples each. Seven cassettes fit into a standard dry shipping Dewar. The capabilities of a robotic crystal mounting and alignment system with instrumentation control software and a relational database allows for automated screening and data collection to be developed.