Advanced Photon Source Storage Ring Orbit Correction at 10 Hz

L. Emery

APS Operations Division, Argonne National Laboratory

Direct-current orbit correction is performed in the Advanced Photon Source (APS) with a 10-Hz iteration rate in order to eliminate short-term orbit perturbations such as those produced by insertion device (ID) gap motion. The same software can also perform steering of the photon beams at the users' request. The previous version of the full-feature feedback software ran on a workstation and was limited in speed by the APS control system network. The feedback software now runs on an input/output controller that has access to the fast dedicated network that the real-time feedback system (RTFS) uses, allowing for up to 30-Hz iteration rate. Special features will be reported, such as inclusion of x-ray beam position monitors and feed-forward compensation of frequency band overlap with the RTFS. Also described are workstation-based helper applications, such as feed-forward of ID x ray offsets on ID gap value.

Routine Achievement of 200 Nanoradian RMS Pointing Stability of Insertion Device Beams Using X-ray Beam Position Monitors

G. Decker and O. Singh

APS Operations Division, Argonne National Laboratory

Since routine operation of the Advanced Photon Source (APS) began c. 1996, the storage ring orbit correction systems have incrementally evolved to their present configuration. Most recently, insertion device x-ray beam position monitors (XBPMs) located in the beamline front ends have been incorporated into the DC global orbit correction algorithm, operated at a 10 Hz update rate. This has given the benefit of improving the DC pointing stability over a 48 h period by up to a factor of 10, to below 200 nrad rms.

This required considerable effort, performed in conjunction with other major upgrades, specifically the addition of 42 bending magnet XBPMs, 62 narrowband radio frequency (rf) BPMs (both types with all new associated data acquisition), and a timing system upgrade for the original monopulse rf BPMs. As a result, the APS is well-positioned to achieve routine 200-nrad-rms pointing stability at insertion device source points over time periods up to 48 h. The different elements describing how this is accomplished will be covered.

Direct Booster Injection Status and Plans

N. Sereno

APS Operations Division, Argonne National Laboratory

Recently, direct injection of the linac beam into the booster has been commissioned and operations crews trained. Presently, direct injection can be used to fill the storage ring in the event the particle accumulator ring (PAR) is unavailable. In the long term it is envisioned that direct injection will be used with storage ring top-up, eliminating the need for the PAR as an injector. Eventually, direct injection could also be used in an "interleaving" mode to allow simultaneous Low-Energy Undulator Test Line (free-electron laser) and top-up operation at the highest linac energies.

Presently, when using direct injection, the storage ring bunch pattern spans several buckets corresponding to the linac macropulse length. Most users can use the direct-injected beam and only users that require single bunch purity would be adversely affected. Simulations of a subharmonic radio frequency cavity in the booster indicate that nearly the complete linac macropulse can captured and single bunch purity preserved. In this poster, measurements of the existing storage ring bunch purity when using direct injection are presented. Finally, results of simulations of linac beam capture using various booster subharmonic cavity configurations are given. The subharmonic simulations will show the basic design tradeoffs involved between subharmonic cavity frequency, gap voltage, and linac macropulse length parameters.

Improvement of Storage Ring Beam Position Missteering Interlock Reliability Using Narrowband Beam Position Monitors and Digital Beam Position Limit Detectors

O. Singh, A. P. Pietryla, and L. Erwin

APS Operations Division, Argonne National Laboratory

An upgrade of the Advanced Photon Source (APS) storage ring beam position missteering interlock system for high-power insertion device beams is in progress and its status will be discussed here. The existing system hardware configuration, installed in 1995, has a number of long-standing maintenance and operations deficiencies and is prone to inducing false trips. An updated digitizing beam position limit detector was developed to interface with new narrow-band beam position monitor (BPM) electronics. This system is robust, reliable, and primarily utilizes existing hardware. Eighty new channels of narrowband radio frequency BPM electronics are presently being installed in the APS storage ring. Many of these new units will serve the dual purpose of enhancing beam stability while providing more reliable beam missteering interlock capability.

Experiment Safety Assessment System

B. Glagola1, S. Davey1, M. Wood1, M. Jamal1,2, and J. Broniarczyk1,2

1 APS Operations Division, Argonne National Laboratory
2 T.U.S.C.

The Advanced Photon Source (APS) has offered a web-based Experiment Safety Approval Form (ESAF) since 1997. This year, the ESAF system was upgraded to comply with the Department of Energy requirement that the APS approve the safety plans for all experiments.

In addition, enhancements were made to the safety information and feedback is now provided to the user population via the ESAF. Improvements were also made to the underlying code and to the ESAF graphical user interface. The ESAF system continues to make use of an ORACLE database and a web-based front end. The redesign of the system was undertaken with the assistance of APS/user beamline personnel, who compiled suggested improvements and additions to the system. The ESAF system consists of four parts: 1) administrative roles and process; 2) the ESAF for collecting experiment-related hazard information; 3) review and approval by both beamline personnel and the APS; and 4) two automatically generated reports, the Experiment Authorization Form and the Experiment Hazard Control Plan, which are posted at the beamline at the beginning of the experiment.

Simulations of Coherent Synchrotron Radiation, Longitudinal Space Charge and Errors in the Linac Coherent Light Source

N. Sereno and M. Borland

APS Operations Division, Argonne National Laboratory

The Advanced Photon Source (APS) has taken a leading role in comprehensive simulations of the Linac Coherent Light Source (LCLS), an x-ray free-electron laser (XFEL) project funded by the Department of Energy at the Stanford Linear Accelerator Center (SLAC). These on-going efforts have resulted in significant changes to the LCLS design and have brought world-wide attention to the APS for our application and development of accelerator simulation codes.

Like any XFEL, the LCLS requires very short (220 fs rms) electron bunches, which are produced by a series of magnetic compression systems. It was anticipated that coherent synchrotron radiation (CSR) in these systems might corrupt beam quality. The APS has the distinction of having discovered a CSR-driven microbunching instability in such systems. Our discovery resulted directly in a redesign of the LCLS systems. More recently, researchers at the Deutsches Elektronen Synchrotron postulated a similar, more serious instability driven by longitudinal space charge. The APS, working with researchers at SLAC, was the first to simulate this effect for an entire XFEL. We confirmed that the effect is very damaging and also evaluated a proposed cure. Finally, the APS has the distinction of being the only facility to perform comprehensive simulation of jitter effects for an XFEL, leading to refinement of jitter specifications and correction methods for the LCLS.

Recent Developments/Upgrades of the Advanced Photon Source Diagnostics Beamlines (Sector 35) and Real-Time Display of Electron Beam Images for User Operation

B. Yang1, A. Lumpkin1, N. D. Arnold2, K. Evans, Jr. 2,
S. Shoaf2, and S. Sharma2

1 APS Operations Division, Argonne National Laboratory
2 Accelerator Systems Division, Argonne National Laboratory

Sector 35 at the Advanced Photon Source (APS) is dedicated to storage ring electron beam diagnostics. The stored beam sizes are measured with pinhole cameras at bending magnet (BM) source 35-BM and diagnostics undulator source 35-ID. The electron beam divergence is measured with monochromatic beam from the undulator. To ensure easy access by the users, beam information is distributed in real time through four channels. All measured beam parameters are available as process variables. All three beam images are broadcasted through the APS closed-circuit video system and are available via the APS intranet in two different formats: through a high-resolution-graphics web page that is updated once a minute, or through a low-resolution web-video server updating at five frames per second. In August 2003, we started commissioning of a cryogenically cooled silicon monochromator, which will improve the angular resolution of the beam divergence measurements by using the third undulator harmonic radiation and allow high-speed imaging with several microradian resolutions. Preliminary commissioning data will be shown. The progress of a new pinhole camera at the BM source with resolution of 10 µm or better will also be reported.

Nonintercepting Imaging Diagnostics for the Advanced Photon Source During Storage Ring Top-Up Operations

A. H. Lumpkin1, W. J. Berg1, S. Shoaf2, and B. X. Yang1

1 APS Operations Division, Argonne National Laboratory
2 Accelerator Systems Division, Argonne National Laboratory

The recently implemented top-up operating mode of the Advanced Photon Source storage ring has motivated an emphasis on nonintercepting imaging diagnostics in the injectors. We present the upgrades to the optical synchrotron radiation (OSR) monitors on the accumulator ring and injector synchrotron, as well as plans for a new OSR monitor on a chicane dipole in the linac and for an optical diffraction radiation (ODR) monitor for the 7-GeV transport line to the storage ring. Two key issues are signal strength for a single macropulse in the chicane and discriminating key transverse information from the visible-light ODR. We also will be evaluating locations for OSR or ODR imaging in support of direct injection or interleaving operations.

Central Web Registration for All Department of Energy/Basic Energy Sciences National User Facilities at Argonne National Laboratory

S. Strasser1, M. Wood1, F. Lacap1,5, E. Kolsto2, M. Heinig1, R. Cook3, and E. Kaufmann4

1 APS Operations Division,
2 Office of Safeguards and Security,
3 Materials Science Division,
4 Office of the Director, Argonne National Laboratory
5 T.U.S.C.

The planned siting of the Center for Nanoscale Materials at Argonne National Laboratory (ANL) provided the impetus for a proposal to facilitate access for all of ANL’s Department of Energy/Basic Energy Sciences (DOE/BES) national user facilities: Advanced Photon Source, Center for Nanoscale Materials, Electron Microscopy Center, and Intense Pulsed Neutron Source. A working group consisting of representatives of these facilities, the ANL Foreign Visits and Assignments Office, and the ANL Office of the Director proposed the creation of a uniform web registration process, coupled to the creation of a central user database — the User Data Warehouse (UDW). A prospective user will be able to register electronically through the ANL Central User Interface for access to any or all of the user facilities for a single or multiple visit(s). Once a user’s information has been validated and placed in the UDW, it will be electronically transferred to the ANL Human Resources database and the ANL Foreign Visits and Assignment system, if applicable. Each facility will be able to access and download information from the UDW for further facility-specific manipulation and reporting purposes. All users will receive ANL badge numbers; user training will be recorded in ANL’s Training Management System. The prototype system should be operational by October 1, 2003. A flow chart for the entire system and web registration pages will be presented.

How We Do Business at the Advanced Photon Source

G. Banks, C. Y. Yao, G. Decker, and R. Klaffky

APS Operations Division, Argonne National Laboratory

The Advanced Photon Source (APS) storage ring is a third-generation dedicated x-ray synchrotron radiation user facility, which has been in operation since 1996. We report the organization of the operations team, machine performance, operation modes, user beam schedule, user interaction, and other aspects of APS.

Automated Operation of the Advanced Photon Source Linac

S. Pasky1, R. Soliday1, M. Borland1, J. Stein2, and R. Koldenhoven2

1 APS Operations Division, Argonne National Laboratory
2 Accelerator Systems Division, Argonne National Laboratory

In recent years many changes have been made to the Advanced Photon Source (APS) linear accelerator (linac) to support multiple tasks. The primary purpose of the linac is to provide beam to fill the APS storage ring, which is done using thermionic cathode radio frequency (rf) guns. At the same time, we provide support for research projects, including a new facility that will be used for future operator training and testing of injector components. With each task requiring a different lattice and timing configuration, while at the same time using common rf systems, the complexity of operations has increased significantly, with even greater demands being made on reliability and performance. In addition, personnel safety and equipment protection concerns have become more complex. We approached these challenges by developing three new subsystems: a highly automated linac operation using APS's Procedure Execution Manager software; a new interlock system based on programmable logic controllers; and an automated S-band rf switching system.

Floor Coordinators: The First Line of User Support

W. Wesolowski and K. Beyer

APS Operations Division, Argonne National Laboratory

The floor coordinators represent the Advanced Photon Source (APS) as the point of contact for the day-to-day activities of beamline personnel. Floor coordinators have primary responsibility for oversight of beamline operations. They must provide high-quality technical support, understand all safety subsystems, and effectively communicate with the user community and APS/Argonne National Laboratory support groups. The floor coordinators are strategically located in offices directly adjacent to the APS experiment hall. Their scientific backgrounds are varied to better represent the diverse scientific research performed at APS. The floor coordinators are present on site 24/7 during user runs (beam available for experimentation) and are on call 24/7/365. Although assigned to specific locations in the experiment hall, floor coordinators must be familiar with the entire facility in order to perform their duties. Up-to-date documentation for each beamline is maintained in display cabinets at the end of each sector. Floor coordinators are adept at using the Experimental Physics and Industrial Control System software that is employed to monitor, control, and troubleshoot APS systems. Floor coordinators are intimately involved with the management of shielding configuration-controlled components, working closely with Health Physics and the radiation scientist. Configuration-controlled components are administratively maintained, documented, and repeatedly verified whenever work is performed upon them and prior to each user run. Additionally, the floor coordinators are responsible for the liquid-nitrogen distribution system, which delivers nitrogen to the individual beamlines. In summary, the floor coordinators facilitate user requests and seek out solutions to user problems.

Advanced Photon Source Experiment Hall / Laboratory-Office Module Data Network Upgrade

W. McDowell and K. Sidorowicz

APS Operations Division, Argonne National Laboratory

The Advanced Photon Source (APS) experiment hall/laboratory office module (LOM) data network is in the process of being upgraded to improve its overall capacity, speed, and reliability. Previously, the central network switch, a Cisco 6509, had a supervision card capable of 65 Gbits/s. This switch is being upgraded with a new supervision card capable of 720 Gbits/S. Each LOM has a switch/router. Previously the switch was a Cisco 5500 consisting of 1 Supervisor Card, 5 - 24 port 10/100 ports (24/cat, 1-APS), 3 Gigabit backplane, 1 active Gbyte uplink, 1 standby Gbyte uplink, and redundant power supplies. The patch panels in the network closet supported 10/100 Mbits/S. These switches have been upgraded to a Cisco 4507R consisting of 2 supervisor cards (to provide redundancy), a 64-Gigabit backplane, 2 active Gbit uplinks (to provide redundancy + 4 Gbit/S full duplex), 1 standby Gbit uplink (to provide redundancy), and redundant power supplies. The patch panels in the network closet have been upgraded to support 10/100/1000 M Bit/S. This now provides 4 Gbit fiber ports/beamline and 30 10/100/1000MBit/S ports/beamline. In addition to the backbone upgrades, wireless networking is being added to the LOMs and experiment hall areas. The wireless network allows the APS community to access APS network services and the internet via their laptop computers without having to plug in to the network. Each LOM pentagon has a wireless access point and the experiment hall has access points mounted on the wall of the mechanical mezzanine. The wireless system uses the 802.11b standard. The APS has installed a Vocera system that allows voice communication with people wearing a Vocera device (a small receiver/transmitter) over the APS 802.11b wireless network for transport. Using voice prompts, Vocera instantly connects users to the people they need, thereby reducing phone tag, overhead paging, or the need to physically search for a person. This improves the responsiveness of groups responding to user needs.