[en] During the last CDF experimental period from 6/88 to 6/1/89, radiation measurements were made inside the detector on or near the beampipe using various types of monitors. The purpose of the tests was to help predict the radiation levels for future electronics which must be located close to the interaction area. The results from two different types of monitors, PIN diodes and TLD's are reported in this paper. The TLD's (Harshaw/Filtrol type 700) are sensitive to x-rays, gammas, alphas, electrons, and protons. They are calibrated against a cesium source and corrected for nonlinear effects at higher radiation levels. The PIN diodes (Harshaw/Filtrol type DN-156) are sensitive only to neutrons. The devices are calibrated for 1 MeV neutrons and require correction factors for neutrons at other energy levels. All of the monitors were placed just outside of the VTPC, but still inside the CDF magnetic field. The monitors were located 68 inches from the center of the interaction region. The beam pipe is 2 inches in diameter. Therefore the closest monitoring points were on the beampipe or 1 inch from the beam. 5 figs., 2 tabs

[en] The CAMEX64 is a 64 channel full custom CMOS chip designed specifically for the readout of silicon strip detectors. CAMEX which stands for CMOS Multichannel Analog MultiplEXer for Silicon Strip Detectors was designed by members of the Franhofer Institute for Microelectronic Circuits and Systems and the Max Planck Institute for Physics and Astrophysics. Each CAMEX channel has a switched capacitor charge sensitive amplifier with 4 sampling capacitors and a multiplexing scheme for reading out each of the channels on an analog bus. The device uses multiple sampling capacitors to filter and reduce input noise. Filtering is controlled through sampling techniques using external clocks. The device operates in a double correlated sampling mode and therefore cannot separate detector leakage current from a charge input. Normal operation of this device is similar to all other silicon readout chips designed and built thus far in that there is a data acquisition cycle during which charge is simultaneously accepted on all channels for a short period of time from a detector array, followed by a readout cycle where that charge or hit information is read out. This device works especially well for colliding beam experiments where the time of charge arrival is accurately known. However it can be used in fixed target or asynchronous mode where the time of charge arrival is not well known. In the asynchronous mode it appears that gain is somewhat dependent on the time interval required to decide whether or not to accept charge input information and thus the maximum signal to noise performance found with the synchronous mode may not be achieved in the asynchronous mode. 18 figs., 5 tabs

[en] A new preamplifier for particle detectors has been designed and built for the Fermilab VTPC by Fujitsu of Japan. The device, designated MB43458, is a semi-custom monolithic assembled in a small, low mass package. The purpose of this report is to document the preliminary tests which have been done thus far. Tests are continuing to expand upon the results presented herein

No abstract available

[en] During early operation of the Fermilab Main Accelerator, tune fluctuations, caused by the SCR-controlled power supplies in the quad bus, limited the beam aperature at low energies. To correct this problem, two transistorized power supplies were built in 1975 to regulate and filter the main ring quad magnet current during injection and beam acceleration through the rf transistion region. There is one power supply in series with each quad bus. Each supply uses 320 parallel power transistors and is rated at 300A, 120V. Since the voltage and current capabilities of the transistorized supplies are limited, the supplies are turned-off at about 25GeV. A real-time computer system initiates turn-on of the SCR-controlled power supplies and regulation takeover by the SCR-controlled supplies, at the appropriate times

[en] Modern conventional and superconducting accelerators often require bipolar power supplies capable of operating with high precision from zero to full output. An SCR type power supply comprised of two SCR bridges and operating with circulating current does an excellent job of satisfying this difficult requirement. Power supplies of this type are often called four-quadrant or dual converter power supplies with circulating current. The basic principles and design considerations of this converter are discussed with particular emphasis on the advantages of the converter. Application of the dual converter to high precision bipolar magnet current control within the Fermilab Saver/Doubler project is presented. 4 refs

[en] A group at Lawrence Berkeley Laboratory has reported an elegant CMOS VLSI circuit for amplifying, discriminating, and encoding the signals from highly-segmented charge output devices, e.g., silicon strip detectors or pad readout structures in gaseous detectors. The design exploits switched capacitor circuits and the well-known time structure of data acquisition in colliding beam accelerators to cancel leakage effects and switching noise. For random inputs, these methods are not directly applicable. However, the high speed of the reset switches makes possible a mode of operation for fixed target experiments that uses fast resets to erase unwanted data from random triggers. Data acquisition in this mode has been performed. Details of operation and measurements of noise and rate capability will be presented. 8 refs., 6 figs

[en] Subharmonic ripple in a magnet power supply output can cause unwanted low-frequency field ripple in a magnet load. Among other things the ripple may be caused by SCR firing circuit imbalance. In critical applications, simply providing equally spaced SCR firing pulses, as is done in some all digital control schemes, may not be sufficient. This study discusses in general the causes of subharmonic ripple and some approaches to the problem. A negative feedback scheme utilizing bandpass filters is analyzed and applied to a group of twelve phase .5MW power supplies. Results are given which show a substantial improvement in power supply voltage and magnet field ripple content at 60, 120, and 180 Hz

[en] A new preamplifier ASIC has been designed and built to improve performance of the VTPC (Vertex Time Projection Chamber) at Fermilab's Colliding Detector Facility. Design of the semicustom IC was completed using a Tektronix Quick-Chip 2S bipolar linear array. The ASIC has 6 channels on a chip and provides lower noise, higher gain, lower power, and lower mass packaging than the device which it replaces. Actual performance of the preamplifier was found to match very closely the simulated performance. To reduce the mass of the complete circuit board, bare IC dice were mounted directly on a G-10 substrate using COB (chip on board) techniques. The preamplifier and packaging should be applicable to numerous other systems. 1 ref

[en] A high speed, high gain amplifier system has been designed for silicon strip detectors. The amplifier has been designed using a semicustom bipolar linear array. This paper focuses on a practical integration of this amplifier into a working system. To maximize board density and reduce cost a new, relatively inexpensive custom chip carrier was designed. The design approach could be useful for other custom or semicustom chip designs. Insight into the design of a 128 channel preamplifier circuit board for low noise and low crosstalk using the new carrier is presented. High channel density presents challenges in cabling. A relatively new high density cable with mass termination capability was used for transmitting signals from the preamp to the discriminator boards. As a part of the overall design, the approach taken for shielding of the detector, preamplifier cards, and output cables is discussed