110266088
The preliminary laser control system for the TRIUMF optically pumped polarized ion source
A system to provide detailed information on control parameters for the lasers used in the optically pumped polarized ion source at TRIUMF has been constructed. The authors describe the overall structure of the system and give details of the instrumentation used. Test and control programs to operate some of the devices and implement a slow spin-flipping operation have been developed and run on the workstation. During initial tests laser beam positions were found to be more stable than expected, and the requirement for controlling mirror motors and beam position detectors has been dropped from the final system. Laser frequency drift was less in the temperature-controlled laser room than in initial tests. >
61175398
VAX Q-bus to CAMAC systems crate interface for long CAMAC branches
The TRIUMF Central Control System (CCS) was to be upgraded to use Q-bus-based VAXs. The CCS consists of multiple computers interfaced to a CAMAC Executive Crate with long parallel branches containing multiple pairs of differential branch extenders (DBE). The Creative Electronics System SCI 2280 systems crate interface used for the Q-bus VAX requires the CAMAC operation to complete synchronously with the Q-bus cycle in less than the Q-bus timeout period. This translates to a maximum branch length of about 150 meters containing three pairs of DBEs, which was not adequate. A Q-bus-to-SCI 2280 interface was built to allow CAMAC cycles to be decoupled, when desired, from the Q-bus cycles. When cycles are decoupled, completion of the CAMAC part can be ascertained by testing flags in the interface. The interface design and operation are described and the results of tests using a VAX 3500 are given.<<ETX>>
54602717
Experience with the TRIUMF Main Tank Vacuum Control System
The TRIUMF Main Tank Vacuum Control System was upgraded in 1984. The earlier system, which consisted of a collection of hardwired relay logic boxes housed in three standard instrumentation racks, was replaced with a compact and flexible microprocessor-based control system. The user interface, previously distributed over the three racks, was consolidated into a single hardwired control and mimic panel. Since 1984, the Main Tank Vacuum System has undergone a series of changes in configuration and vacuum pumping hardware with necessary changes being implemented in the control system logic. Corresponding changes to the user interface were sometimes difficult to implement and in time exhausted the spare input/output capacity which had been built in to the panel. The availability of inexpensive personal computers with adequate graphics capability and the ease of modifying, or adding to a programmable user interface precipitated the retirement of the hardwired panel and its replacement by a PC-based graphics user interface. System configuration, safety considerations, the hardware and the software implementation using the 'C' programming language are described. The evolution of the control system and its performance, both over the years and in adapting to the vacuum system changes, are discussed.<<ETX>>
107947607
RECENT DEVELOPMENTS IN THE TRIUMF CONTROL SYSTEM
The principle ideas and underlying architecture of the TRIUMF Central Control System have not changed since its commissioning in 1974. As described elsewhere 1,2,3 the system consists of a number of Data General minicomputers which communicate using a proprietary Data General parallel direct memory access interprocessor bus, and which share access to a common multiported memory containing a limited descriptive data base of device addresses and pointers to acquisition and conversion routines (Figure 1). The most important idea of the TRIUMF Control System design, and one which has in large measure determined the manner of its evolution, is the use of the executive crate, by means of which all central system computers share direct and immediate access to the entire seven parallel branch CAM.4C system, which in turn interfaces all accelerator devices and most of the main Control Room console devices. Expansion of the Control System to date has been realized on one hand by the addition of CAM.4C crates, and on the other by the addition of minicomputers to the executive crate interface. With the use of active extenders. the executive crate has been extended to three CAMAC crates. and could in principle clcctrically support as many as 1500 sources. In practice, this number is limited to a.bout 30 sources by bandwidth considerations, and to even fewer by the geographical requirement that sources be located physically within about 50 ft. (I/O bus length limitation) of the executive crate. This paper describes three recent developments in the TRIIJMF system whose designs have been influenced by its multisourced architecture. These are:
137947355
Fabrication and Installation of Radio Frequency System for K500 Superconducting Cyclotron at Kolkata
122930946
Holographic dark energy model with linearly varying deceleration parameter and generalised Chaplygin gas dark energy model in Bianchi type-I universe
The paper deals with a spatially homogeneous and anisotropic Bianchi type-I universe filled with two minimally interacting fluids; matter and holographic dark energy components. The nature of the holographic dark energy for Bianchi type-I space time is discussed. An exact solution to Einstein’s field equations in Bianchi type-I line element is obtained using the assumption of linearly varying deceleration parameter. Under the suitable condition, it is observed that the anisotropy parameter of the universe approaches to zero for large cosmic time and the coincidence parameter increases with increasing time. We established a correspondence between the holographic dark energy models with the generalised Chaplygin gas dark energy model. We also reconstructed the potential and dynamics of the scalar field which describes the Chaplygin cosmology. Solution of the field equations shows that a big rip type future singularity will occur for this model. It has been observed that the solutions are compatible with the results of recent observations.
119541770
Local currents for a deformed algebra of quantum mechanics with a fundamental length scale
We explore some explicit representations of a certain stable deformed algebra of quantum mechanics, considered by R Vilela Mendes, having a fundamental length scale. The relation of the irreducible representations of the deformed algebra to those of the (limiting) Heisenberg algebra is discussed, and we construct the generalized harmonic oscillator Hamiltonian in this framework. To obtain local currents for this algebra, we extend the usual nonrelativistic local current algebra of vector fields and the corresponding group of diffeomorphisms, modelling the quantum configuration space as a commutative spatial manifold with one additional dimension.
119062307
Comments on the renormalizability of the Broken Phase in Noncommutative Scalar Field Theory
We study the noncommutative 4 theory with spontaneously broken global O(2) symmetry in 4 dimensions. We demonstrate the renormalizability at one loop. This does not require any choice of ordering of the fields in the interaction terms. It involves regulating the ultraviolet and infrared divergences in a manner consistent with the Ward identities.
59390087
A Grid job monitoring system
This paper presents a web-based Job Monitoring framework for individual Grid sites that allows users to follow in detail their jobs in quasi-real time. The framework consists of several independent components : (a) a set of sensors that run on the site CE and worker nodes and update a database, (b) a simple yet extensible web services framework and (c) an Ajax powered web interface having a look-and-feel and control similar to a desktop application. The monitoring framework supports LSF, Condor and PBS-like batch systems. This is one of the first monitoring systems where an X.509 authenticated web interface can be seamlessly accessed by both end-users and site administrators. While a site administrator has access to all the possible information, a user can only view the jobs for the Virtual Organizations (VO) he/she is a part of. The monitoring framework design supports several possible deployment scenarios. For a site running a supported batch system, the system may be deployed as a whole, or existing site sensors can be adapted and reused with the web services components. A site may even prefer to build the web server independently and choose to use only the Ajax powered web interface. Finally, the system is being used to monitor a glideinWMS instance. This broadens the scope significantly, allowing it to monitor jobs over multiple sites.