29 research outputs found
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Information-Control Software for Handling Serial Devices in an EPICS Environment
No full textEach accelerator control system has a variety of measurement devices. One of the most common types of instrument interfaces used for their control is a serial (RS-232) bus. It is inexpensive and adequate for relatively simple measurement and control devices such as switchers, amplifiers, voltmeters, and stepper motors. Since the RS-232 specification is very broad and does not require uniformity above the basic communication protocol level, one of the major problems associated with the use of RS-232 is that a fundamental understanding of the details of each device's command protocol is required. This makes writing reliable control software difficult and also hampers efforts to design effective, generic troubleshooting methods for RS-232. This paper presents software developed at Jefferson Lab to handle serial devices in a generic manner. The software is based on the EPICS toolkit and uses a 3-tier architecture which includes a common serial driver at the bottom, a top-level protocol to specify individual device commands in a generic manner, and a mid-level of software to glue the two together
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Correction of the Chromaticity up to Second Order for MEIC
No full textThe proposed electron collider lattice exhibits low β- functions at the Interaction Point (IP) (βx∗100mm − βy∗ 20 mm) and rather large equilibrium momentum spread of the collider ring (δp/p = 0.00158). Both features make the chromatic corrections of paramount importance. Here the chromatic effects of the final focus quadruples are cor- rected both locally and globally. Local correction features symmetric sextupole families around the IP, the betatron phase advances from the IP to the sextupoles are chosen to eliminate the second order chromatic aberration. Global interleaved families of sextupoles are placed in the figure-8 arc sections, and non-interleaved families at straight sec- tion making use of the freely propagated dispersion wave from the arcs. This strategy minimizes the required sex- tupole strength and eventually leads to larger dynamic aper- ture of the collider. The resulting spherical aberrations induced by the sextupoles are mitigated by design; the straight and arc sections optics features an inverse identity transformation between sextupoles in each pair
BEAM EMITTANCE MEASUREMENT TOOL FOR CEBAF OPERATIONS
No full textAbstract A new software tool was created at Jefferson Lab to measure the emittance of the CEBAF electron beams. The tool consists of device control and data analysis applications. The device control application handles the work of wire scanners and writes their measurement results as well as the information about accelerator settings during these measurements into wire scanner data files. The data analysis application reads these files and calculates the beam emittance on the basis of a wire scanner data processing model. Both applications are computer platform independent but are mostly used on LINUX PCs recently installed in the accelerator control room. The new tool significantly simplifies beam emittance measurement procedures for accelerator operations and contributes to a very high availability of the CEBAF machine for the nuclear physics program at Jefferson Lab
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Spin Rotator Optics for MEIC
No full textA unique design feature of a polarized Medium Energy Electron-Ion Collider (MEIC) based on CEBAF is its 'Figure-8' storage rings for both electrons and ions, which significantly simplifies beam polarization maintenance and manipulation. While electron (positron) polarization is maintained vertical in arcs of the ring, a stable longitudinal spin at four collision points is achieved through solenoid based spin rotators and horizontal orbit bends. The proposed MEIC lattice was developed in order to preserve a very high polarization (more than 70%) of the electron beams injected from the CEBAF machine. The otherwise coupled beam trajectory due to solenoids used in the spin rotators was decoupled by design. Aspin matching technique needs to be implemented in order to enhance quantum self-polarization and minimize depolarization effects
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PLC Support Software at Jefferson Lab
No full textSeveral Automation Direct (DirectNet) Programmable Logic Controllers (PLCs) have been integrated into the accelerator control system at Jefferson Lab. The integration is based on new software that consists of three main parts: a PLC driver with a state machine control block, a device support module, and a common serial driver. The components of new software and experience gained with the use of this software for beam dump systems at Jefferson Lab are presented
A versatile trigger and synchronization module with IEEE1588 capabilities and EPICS support.
No full textEvent timing and synchronization are two key aspects to improve in the implementation of distributed data acquisition (dDAQ) systems such as the ones used in fusion experiments. It is also of great importance the integration of dDAQ in control and measurement networks. This paper analyzes the applicability of the IEEE1588 and EPICS standards to solve these problems, and presents a hardware module implementation based in both of them that allow adding these functionalities to any DAQ. The IEEE1588 standard facilitates the integration of event timing and synchronization mechanisms in distributed data acquisition systems based on IEEE 803.3 (Ethernet). An optimal implementation of such system requires the use of network interface devices which include specific hardware resources devoted to the IEE1588 functionalities. Unfortunately, this is not the approach followed in most of the large number of applications available nowadays. Therefore, most solutions are based in software and use standard hardware network interfaces. This paper presents the development of a hardware module (GI2E) with IEEE1588 capabilities which includes USB, RS232, RS485 and CAN interfaces. This permits to integrate any DAQ element that uses these interfaces in dDAQ systems in an efficient and simple way. The module has been developed with Motorola's Coldfire MCF5234 processor and National Semiconductors's PHY DP83640T, providing it with the possibility to implement the PTP protocol of IEEE1588 by hardware, and therefore increasing its performance over other implementations based in software. To facilitate the integration of the dDAQ system in control and measurement networks the module includes a basic Input/Output Controller (IOC) functionality of the Experimental Physics and Industrial Control System (EPICS) architecture. The paper discusses the implementation details of this module and presents its applications in advanced dDAQ applications in the fusion community
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Ion polarization in the MEIC figure-8 ion collider ring
No full textThe nuclear physics program envisaged at the Medium-energy Electron-Ion Collider (MEIC) currently being developed at the Jefferson Lab calls for collisions of 3-11 GeV/c longitudinally polarized electrons and 20-100 GeV/c, in equivalent proton momentum, longitudinally/ transversely polarized protons/ deuterons/ light ions. We present a scheme that provides the required ion polarization arrangement in the MEIC's ion collider ring
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High-Level Application Framework for LCLS
No full textA framework for high level accelerator application software is being developed for the Linac Coherent Light Source (LCLS). The framework is based on plug-in technology developed by an open source project, Eclipse. Many existing functionalities provided by Eclipse are available to high-level applications written within this framework. The framework also contains static data storage configuration and dynamic data connectivity. Because the framework is Eclipse-based, it is highly compatible with any other Eclipse plug-ins. The entire infrastructure of the software framework will be presented. Planned applications and plug-ins based on the framework are also presented
