ICALEPCS2011 - List of Authors (Krejcik, P.)

Paper

Title

Page

Development of Pattern Awareness Unit (PAU) for the LCLS Beam Based Fast Feedback System

954

K.H. Kim, S. Allison, D. Fairley, T.M. Himel, P. Krejcik, D. Rogind, E. Williams
SLAC, Menlo Park, California, USA

LCLS is now successfully operating at its design beam repetition rate of 120 Hz, but in order to ensure stable beam operation at this high rate we have developed a new timing pattern aware EPICS controller for beam line actuators. Actuators that are capable of responding at 120 Hz are controlled by the new Pattern Aware Unit (PAU) as part of the beam-based feedback system. The beam at the LCLS is synchronized to the 60 Hz AC power line phase and is subject to electrical noise which differs according to which of the six possible AC phases is chosen from the 3-phase site power line. Beam operation at 120 Hz interleaves two of these 60 Hz phases and the feedback must be able to apply independent corrections to the beam pulse according to which of the 60 Hz timing patterns the pulse is synchronized to. The PAU works together with the LCLS Event Timing system which broadcasts a timing pattern that uniquely identifies each pulse when it is measured and allows the feedback correction to be applied to subsequent pulses belonging to the same timing pattern, or time slot, as it is referred to at SLAC. At 120 Hz operation this effectively provides us with two independent, but interleaved feedback loops. Other beam programs at the SLAC facility such as LCLS-II and FACET will be pulsed on other time slots and the PAUs in those systems will respond to their appropriate timing patterns. This paper describes the details of the PAU development: real-time requirements and achievement, scalability, and consistency. The operational results will also be described.

Poster WEPMN032 [0.430 MB]

FRAAUST01

Development of the Machine Protection System for LCLS-I

1281

J.E. Dusatko, M. Boyes, P. Krejcik, S.R. Norum, J.J. Olsen
SLAC, Menlo Park, California, USA

Funding: U.S. Department of Energy under Contract Nos. DE-AC02-06CH11357 and DE-AC02-76SF00515
Machine Protection System (MPS) requirements for the Linac Coherent Light Source I demand that fault detection and mitigation occur within one machine pulse (1/120th of a second at full beam rate). The MPS must handle inputs from a variety of sources including loss monitors as well as standard state-type inputs. These sensors exist at various places across the full 2.2km length of the machine. A new MPS has been developed based on a distributed star network where custom-designed local hardware nodes handle sensor inputs and mitigation outputs for localized regions of the LCLS accelerator complex. These Link-Nodes report status information and receive action commands from a centralized processor running the MPS algorithm over a private network. The individual Link-Node is a 3u chassis with configurable hardware components that can be setup with digital and analog inputs and outputs, depending upon the sensor and actuator requirements. Features include a custom MPS digital input/output subsystem, a private Ethernet interface, an embedded processor, a custom MPS engine implemented in an FPGA and an Industry Pack (IP) bus interface, allowing COTS and custom analog/digital I/O modules to be utilized for MPS functions. These features, while capable of handing standard MPS state-type inputs and outputs, allow other systems like beam loss monitors to be completely integrated within them. To date, four different types of Link-Nodes are in use in LCLS-I. This paper describes the design, construction and implementation of the LCLS MPS with a focus in the Link-Node.

Slides FRAAUST01 [3.573 MB]

Paper	Title	Page
WEPMN032	Development of Pattern Awareness Unit (PAU) for the LCLS Beam Based Fast Feedback System	954
	K.H. Kim, S. Allison, D. Fairley, T.M. Himel, P. Krejcik, D. Rogind, E. Williams SLAC, Menlo Park, California, USA
	LCLS is now successfully operating at its design beam repetition rate of 120 Hz, but in order to ensure stable beam operation at this high rate we have developed a new timing pattern aware EPICS controller for beam line actuators. Actuators that are capable of responding at 120 Hz are controlled by the new Pattern Aware Unit (PAU) as part of the beam-based feedback system. The beam at the LCLS is synchronized to the 60 Hz AC power line phase and is subject to electrical noise which differs according to which of the six possible AC phases is chosen from the 3-phase site power line. Beam operation at 120 Hz interleaves two of these 60 Hz phases and the feedback must be able to apply independent corrections to the beam pulse according to which of the 60 Hz timing patterns the pulse is synchronized to. The PAU works together with the LCLS Event Timing system which broadcasts a timing pattern that uniquely identifies each pulse when it is measured and allows the feedback correction to be applied to subsequent pulses belonging to the same timing pattern, or time slot, as it is referred to at SLAC. At 120 Hz operation this effectively provides us with two independent, but interleaved feedback loops. Other beam programs at the SLAC facility such as LCLS-II and FACET will be pulsed on other time slots and the PAUs in those systems will respond to their appropriate timing patterns. This paper describes the details of the PAU development: real-time requirements and achievement, scalability, and consistency. The operational results will also be described.
	Poster WEPMN032 [0.430 MB]

FRAAUST01	Development of the Machine Protection System for LCLS-I	1281
	J.E. Dusatko, M. Boyes, P. Krejcik, S.R. Norum, J.J. Olsen SLAC, Menlo Park, California, USA
	Funding: U.S. Department of Energy under Contract Nos. DE-AC02-06CH11357 and DE-AC02-76SF00515 Machine Protection System (MPS) requirements for the Linac Coherent Light Source I demand that fault detection and mitigation occur within one machine pulse (1/120th of a second at full beam rate). The MPS must handle inputs from a variety of sources including loss monitors as well as standard state-type inputs. These sensors exist at various places across the full 2.2km length of the machine. A new MPS has been developed based on a distributed star network where custom-designed local hardware nodes handle sensor inputs and mitigation outputs for localized regions of the LCLS accelerator complex. These Link-Nodes report status information and receive action commands from a centralized processor running the MPS algorithm over a private network. The individual Link-Node is a 3u chassis with configurable hardware components that can be setup with digital and analog inputs and outputs, depending upon the sensor and actuator requirements. Features include a custom MPS digital input/output subsystem, a private Ethernet interface, an embedded processor, a custom MPS engine implemented in an FPGA and an Industry Pack (IP) bus interface, allowing COTS and custom analog/digital I/O modules to be utilized for MPS functions. These features, while capable of handing standard MPS state-type inputs and outputs, allow other systems like beam loss monitors to be completely integrated within them. To date, four different types of Link-Nodes are in use in LCLS-I. This paper describes the design, construction and implementation of the LCLS MPS with a focus in the Link-Node.
	Slides FRAAUST01 [3.573 MB]