Student Abstracts: Computer Science at SLAC

Evaluation of the use and maintenance of E.P.I.C.S. extension tools at the Stanford Linear Accelerator Center. ROGER BAKER (Calif. State Univ. Bakersfield, Bakersfield, CA 93301) RON CHESTNUT (Stanford Linear Accelerator Center, Stanford, CA 94025) .
Industrial control software development and maintenance at DOE High Energy Physics Laboratories understandably consumes a vast amount of man-hours. Many of these Laboratories have a number of systems in common with each other, and even with industry. For this reason, the EPICS collaboration was born, to reduce the amount of duplicate work being done at various research centers. The base distribution of EPICS has been thoroughly evaluated and critiqued, but the particulars of the maintenance cycle, specifically for the extensions, or add-on tools, has barely been addressed. This project has addressed the specific issues related to installation, maintenance, and upgrade of small, but extremely useful, extensions to the EPICS distribution. We concerned ourselves mainly with use testing, code modification, and software compatibility issues in a collaborative software development environment. Finally, it is our hope, that we have shown the effectiveness of such a development environment, and illustrated ways in which it may be improved, and used as a template for future cooperation.

Development of A XAS Utilities Resource Page Using The JavaScript Programming Language. TIMOTHY CHEERS (Morehouse College, Atlanta, GA 30314-3773) MATTHEW LATIMER (Stanford Linear Accelerator Center, Stanford, CA 94025) .
Researchers performing X-ray Absorption Spectroscopic experiments have an allotted amount of time to collect their data. Most of this time is consumed from having to convert the analyzed data from a photoelectron wave vector (k) to energy (eV) in order to collect this information. Since a k to eV calculator is not readily available, researchers must work endlessly converting the data in order to check for the various other elements that may be found in a sample. Also, the VAX software used in collecting data is incompatible with general PCs. Coding the program to allow compatibility with general PCs may suffer from too many errors. JavaScript, which is a web based programming code integrated into HTML (Hypertext Mark-Up Language), has the ability of being viewable in web browsers enabled with JavaScript software. It is possible to use the JavaScript programming code to construct an X-ray Absorption Spectroscopic Web Resource Page that would be applicable through all computers.

BaBar Database Monitoring and Java. MICHAEL GHEBREBRHAN (Florida A&M Univ., Tallahassee, FL 32307) ADEYEMI ADESANYA (Stanford Linear Accelerator Center, Stanford, CA 94025) .
Knowing BaBar's database growth rate would be of use to collaborators around the world which is why a program to display the data was written. The graph displayed the size of the database in real time, plotting the size in terabytes as a function of time. Using Java, a platform-independent language suited for the internet, a visual can be construct allowing researchers around the world to view the grow of the databases. Java was chosen because executables written in it are platform independent requiring only its Runtime Environment. Since Java is an object-oriented language the approach used was to split important functions into classes with the top most class displaying the graph. At first, though, the solution was considered to be to write a separate application to format the data in a useable way and then have an applet call the application to run when needed and obtain the formatted data. This failed because security restrictions posed on applets prevent them from running executables over a host com puter. The second and successful approach was to create objects that when fitted together produced a graph. Though a program was written to display the graph, the rigorous security, especially in browsers, features makes it difficult to implement classes in a variety of ways. Future programs may include more detailed information of the databases such as information distribution.

Monitoring of the data acquisition of BaBar to search for sources of dead time problems. ANNA HURST (Union College, Schenectady, NY 12308) STEFFEN LUITZ (Stanford Linear Accelerator Center, Stanford, CA 94025) .
There is sometimes unexplained dead time in the data acquisition system of BaBar. It is important to identify the source of this dead time in order to eliminate the problem and avoid loss of data. Some areas of the data acquisition system are already well monitored, but one area that is not is the logging manager. Two programs were developed using Portable Channel Access (PCA). One monitored the amount of network traffic entering and leaving the logging manager. The other monitored the status of the logging manager. Preliminary runs of the programs showed that they could run for periods of several days without crashing and that the results they gave corresponded with the same data retrieved with other system monitoring methods. At this time, no unexplained dead time has occurred and therefore no conclusions about the sources of the dead time can be drawn. The programs will be in continued use to search for the source should a dead time problem occur.

Characterizing Beam Losses and Irradiation of Beam Line Components for SLAC Experiment E158. JUANITA LEE (North Carolina Agricultural and Technical State University, Greensboro, NC 27411) DR. MIKE WOODS (Stanford Linear Accelerator Center, Stanford, CA 94025) .
Experiment E158 will make the first measurement of parity violation in Moller scattering. The experiment is a fixed target experiment in End Station A. The experiment operates with very intense electron beams and is attempting to measure a small (10-7) physics asymmetry. It is important to minimize beam losses and this paper makes a study of such losses in a recent engineering run. Some recommendations are made for preparing for the physics run in 2002.

Design of an Orbit Control Graphic User Interface in MATLAB. SABRINA TURNER (University of Maryland Baltimore County, Baltimore, MD 21250) JEFF CORBETT (Stanford Linear Accelerator Center, Stanford, CA 94025) .
The research done by the SSRL part of SLAC deals with the radiation produced by the electrons that are traveling in the storage ring SPEAR. SPEAR is a large electron storage ring that is 234 meters in circumference. This electron beam needs to be steered somehow. So, as the electron beam travels along the ring, Beam Position Monitors (BPMs) detect the position of the beam and Corrector Magnets are used to deflect the beam so it travels in a circle around the ring. When the electron beam makes contact with a magnet, the electron beam emits high-frequency radiation that turns out to be quite useful for scientific purposes. The intense x-ray radiation can be used by chemists, biologists, geologists and other scientists to x-ray materials. Currently there is a program written in FORTRAN that controls the electron beam. A new program had been written in MATLAB to control the electron. This software has many advantages over the older program including a graphical user interface to control the position of the electron beam. The graphical interface and linear algebra behind it will make it easier for the scientists using the beam to do their research. In order to make this program efficient, flow charts were made for all of the functions and function calls in the program so that multiple unnecessary calls to a function are not made. The graphic user interface was re-worked and additional functional graphical elements were added.