We describe the software architecture of the Longitudinal Feedback System being built for the PEP-II B-Factory at SLAG, the ALS light source at LBL and the DA/spl Phi/NE phi factory at Frascati. This ...VME/VXI based system utilizes commercially available embedded CPU controller boards running the VxWorks real time operating system. The operator interface for PEP-II and ALS is based on the EPICS control system package. Embedded processors are used to load, monitor and diagnose various components of the system. The feedback function is implemented using digital filtering techniques on a DSP farm residing in the VME crates. The operator interface is written to allow the loading of applications, e.g., accelerator diagnostic functions, system hardware integrity functions, etc., without intervening controller reboots.
The DIRC front-end electronics chain for BaBar Bailly, P.; Beigbeder, C.; Bernier, R. ...
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255),
1998, Volume:
2
Conference Proceeding
Recent results from the front-end electronics of the Detector of Internally Reflected Cerenkov light (DIRC) for the BaBar experiment at SLAC (Stanford, USA) are presented. It measures to better than ...1 ns the arrival time of Cerenkov photoelectrons, detected in a 11,000 phototubes array and their amplitude spectra. It mainly comprises 64-channel DIRC front-end boards (DFB) equipped with eight full-custom analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom digital TDC chips for timing measurements with 500 ps binning and a readout logic selecting hits in the trigger window, and DIRC crate controller cards (DCC) serializing the data collected from up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test results of the pre-production chips are presented, as well as system tests.
A modular programmable longitudinal feedback system has been developed as a component of the PEP-II R+D program. This system is based on a family of VME and VXI packaged signal processing functions ...which implement a general purpose digital feedback controller for accelerators with bunch spacings of 2 ns. A complete PEP-II prototype system has been configured and installed for use at the LBL Advanced Light Source. The system configuration used for tests at the ALS is described and results are presented showing the action of the feedback system. Open and closed loop results showing the detection and calculation of feedback signals from bunch motion are presented and the system is shown to damp coupled-bunch instabilities in the ALS. Use of the system for accelerator diagnostics is illustrated via measurement of grow-damp transients which quantify growth rates without feedback, damping rates with feedback, and identify unstable modes.
A low-cost high-voltage readout system has been implemented to offer stand-alone digital readout capability as well as fast data transfer to a host computer. The system is flexible enough to permit ...use of a DVM or ADC and commercially available analogue multiplexers.
The advent of the "personal" microcomputer provides a new tool for the debugging, calibration and monitoring of small scale physics apparatus; e.g., a single detector being developed for a larger ...physics apparatus. With an apropriate interface these microcomputer systems provide a low cost (1/3 the cost of a comparable minicomputer system), convenient, dedicated, portable system which can be used in a fashion similar to that of portable oscilloscopes. Here we describe an interface between the Apple computer and CAMAC which is now being used to study the detector for a Cerenkov ring-imaging device. The Apple is particularly well-suited to this application because of its ease of use, hi-resolution graphics, peripheral buss and documentation support.
The 168/E is a SLAC developed microprocessor which emulates the IBM 360/370 computers with an execution speed of about one half of a IBM 370/168. These processors are used in parallel for the track ...finding and geometry programs of the LASS spectrometer. The system is controlled by a PDP-11 minicomputer via a three port interface which we call the Bermuda Triangle. The tape handling and downloading is controlled by one of SLAC's IBM computers via a SLAC built interface between the PDP-11 and an IBM channel. Initially, there will be a system of 6 168/E's which should be able to give six times the production capacity than can be attained by running production jobs on the SLAC Triplex system. The cost of the system, including the channel interface, is 120,000 and yet it yields the equivalent computer power of 3 IBM 370/168's. Hence, this system is an extremely cost-effective method for off-line data analysis.
PDF
