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It is well-known that while the use of single clipping yields optimum energy resolution in nuclear pulse spectrometry it suffers from the drawback of producing rate-dependent baseline shifts. On the other hand the use of double clipping removes the baseline shift but degrades the signal-to-noise ratio. A scheme has been devised which circumvents some of these problems by producing a signal proportional only to the peak-to-peak excursion of an input signal. When operating with double clipped signals this improves the signal-to-noise ratio and also reduces tail-pile-up difficulties. Single clipped signals can also be used and produce an output amplitude which is independent of baseline position, allowing the use of single clipping at high counting rates, although in this case the system exhibits a noise disadvantage. The technique employed is based on the principle of "active D-C restoration" and circuit details, together with representative results, are given.

The signal on radiation pulse detectors is in the form of a charge on a capacitor. An ionizing particle produces a charge pair for each 3.6 ev dissipated in silicon. The capacitance of a p-n junction is proportional to the area and inversely proportional to the square root of the bias potential. Three similar preamplifier circuits are described. Negative charge feedback is employed so that the output amplitude is essentially independent of the value of the detector capacitance. The amplifiers have a high open loop gain, a fast response, and show little tendency to oscillate. Best overall performance, a noise line width of 5 kv, is achieved using WE417A or equivalent tubes in cascode at the input. RCA 7586 tubes give a line width of 8-10 kv with low capacitance detectors. The line width with transistors is 20-30 kv.

The Bell-Rutgers data highway system is a modular, general purpose system designed to provide a framework in which the configuration and reconfiguration of on-line computer hardware is easily accomplished. It is built using modified NIM hardware, and features a 16 bit parallel data path for input and output which is shared by up to 150 general purpose modules. Special consideration has been given to two particular problems; the operation of modules in an environment in which digital switching noise must be minimized, and the simultaneous use of the module system by several independent users. The initial application of the system has been in the implementation of a computer based nuclear physics data acquisition and analysis system. The following paper is intended as an exposition of some of the considerations which are relevant to the design of any general purpose modular system as well as a description of a particular system. Some of the ways in which the system has been used are also described.

Exploitation of the high resolution and wide energy range of semiconductor radiation detectors imposes severe demands on the linearity and stability of the associated A.D. C. system. A study has been made of various alternative conversion and stabilization schemes with particular reference to their use in a computer-based data gathering system. As a result of this study a 4096 channel 50 Mc/s servo-stabilized ramp converter has been developed. Stabilization is based on a bang-bang servo scheme, the ultimate reference being a mercury double pulse generator. A feature of the design is the ability to dial the energies defining the upper and lower limits of the range of interest. In this way the converter acts as its own window amplifier, always spanning the designated range with 4096 channels. In the design particular attention has been paid to factors affecting the system linearity. Notable among these has been the importance of transient thermal effects in the transistors, and the window expansion scheme which eliminates the problems associated with biased-off amplifiers.

Methods of producing the powders of beryllium, zirconium, titanium, tantalum, and niobium are outlined. The purity level, particle size, storage, and appropriate comments are given corresponding to each production method. The most common impurities are oxygen, nitrogen, hydrogen, and carbon, and their importance depends on the purpose for which the powder is to be used. (B.O.G.)

The instrument described in this paper was built with the purpose of providing a display of the profile of secondary beams from high energy accelerators. It is capable of handling 105 particles per cm2 per machine pulse, assuming a 20 msec spill. The profile is measured by an array of 32 semiconductor detectors, 4 nm apart and arranged in the form of a cross. The detectors count the individual impinging particles. The total numbers of counts on each detector are fed continuously to a multichannel scaler, which in turn delivers an analogue live display and a digital printout. Details of the electronics and methods of fabrication of the detectors, as well as their problems, are discussed.

A large, high-speed random-access memory for the Brookhaven ``Merlin'' digital computer is described. This system employs barrier grid electrostatic storage tubes in a novel configuration yielding improved reliability. Basic design considerations are presented together with a description of circuitry and performance.

The use of semiconductors as scintillation phosphors is discussed. Donoracceptor pair recombination is efficient but it is often slow. The presence of free carriers from high concentrations of electrically active defects causes concentration quenching probably by means of an Auger effect. One is led therefore to consider the use of semiconductors doped with "isoelectronic traps". Experiments are reported for CdS doped with tellurium and ZnTe doped with oxygen. Promising preliminary results have been obtained. For CdS:Te at room temperature using 5 MeV ? particles pulse heights have been recorded 7 times greater than those provided by the scintillator Pilot B, and with a rise time of 300 ns. At 100°K the results are even better. An excellent linearity of response at 100°K was found for particles with energies between 7 keV and 5.2 MeV. In addition to detecting ?, s and ? particles, CdS:Te is also a good potential detector of thermal neutrons.

The operation, properties, and fabrication of semiconductor detectors are reviewed. Materials other than Ge and Si are mentioned only briefly. The electronics involved in use of semiconductors as particle detectors is discussed. Application and possible applications to the following are summarized: nuclear reaction chargedparticle spectroscopy, particle identification, mosaics and special structures, alpha -particle spectroscopy, fission studies, neutron spectroscopy, BETA spectroscopy, gamma spectroscopy, detection of minimum- ionizing particles, low-temperature physics, space vehicles, industry, and medicine.

All charged particles exhibit a minimum in their - dE/dX versus E behaviour. This minimum occurs at relativistic velocities, i.e. high energies, and corresponds to an energy loss of approximately 1.7 Mev gm-1 cm2 for all particles. The application of solid state detectors at high energies depends on obtaining good signals from these minimum ionizing events. Detectors for this application should be large in area, have reasonably thick depletion layers, and a low series resistance to insure fast rise time. Low noise is not a prime requirement however, since the Landau effect in any case limits the resolution to a low value. Using an analyzing magnet and counter telescope at the Brookhaven Cosmotron, diffused silicon junctions of up to 1.5 cm diameter have been investigated using minimum ionizing particles. The signal-to-noise ratio obtained is ~ 10:1 and the resolution ~ 30%.

The application of semiconductor junction radiation detectors1 to penetrating radiation depends on the production of devices having thick depletion layers. In this connection the lithium drift technique developed by Pell2,3,4 has been employed with considerable success5,6,7,8,9. A difficulty encountered with this method is the long time required to produce compensated regions a few millimeters or more in thickness. However it can be shown that the compensated region produced by drifting at constant temperature is proportional to the cube root of the total energy dissipated in the drifting process. This indicates the importance of operating at the highest attainable power at all times, and has led to the design of a system employing a fluorocarbon liquid as a vapor phase coolant in conjunction with a pulsed constant wattage supply. Significantly improved drift rates have been achieved with this technique, which has the added advantage of being well suited to the simultaneous drifting of a number of detectors at constant power from a single power supply.

THE increased use and rise in cost of petroleum fuels has stimulated interest in alcohol as a motor fuel. Ethyl alcohol (ethanol) has received attention since it can easily be produced from renewable resources such as grain. N-butyl alcohol (butanol) can also be produced by a fermentation process and compared to ethanol has several advantages as a fuel supplement. An analysis of gasoline and diesel engine performance was made as the percentage of butanol in the fuel was varied from 0 to 20 percent for the gasoline engine and from 0 to 50 percent for the diesel engine. Parameters measured were torque output and fuel consumption. The effect of butanol on octane rating of gasoline was also de-termined.

A stress questionnaire was developed and administered to employees and students participating in a stress program. The questionnaire consists of three components: stressful conditions, stress symptoms, and measures used to relax. The present study focused on the validation of the stressful conditions portion. Factor analysis demonstrated that the questionnaire had three meaningful factors. Based on the analysis, composite scores were obtained reflecting these three dimensions. Alpha reliability analysis demonstrated that each of the factors was reliable at an acceptable level (r greater than .80). The first factor represented an organizational or external cluster, while the second factor reflected an internal or personal construct. The first factor was shown to correlate negatively with fatigue, worry, agitation, impatience, anger and similar symptoms, while the second factor correlated positively with these complaints. Studies of group differences revealed that defined occupational groups differed on scores for all portions of the questionnaire. In addition, groups participating in a stress management course changed significantly on the first two factors. The third factor related to handling conflict and contained only a few items. Replication studies showed that the factors were stable across different versions of the scales with different groups. The results suggest that the assessment method may be promising for future studies on stress management.

Polyarteritis nodosa is a multisystem disease that involves the gastrointestinal tract in more than 50% of patients at some time during its course. Clinically apparent ischemic disease of the small bowel is the frequent site of involvement. The colon is less commonly involved, particularly as the initial presentation. We present a patient with polyarteritis nodosa noteworthy for prolonged nonbloody diarrhea, ischemic colitis with perforation, and pseudomembrane formation who had histological documentation of polyarteritis nodosa.

A technique for iridectomy in the the treatment of angle-closure glaucoma utilizing laser beams has been developed. The operation is performed in two steps. In step 1 a partially penetrating burn of the iris is made to produce an iris hump. In step 2 a penetrating burn is used to pierce the crown of the previously produced hump. Tables 1, 2, and 3 summarize current recommendations and the detailed steps that must be followed (without exception) to achieve success with this technique. Of 22 phakic eyes, fellow eyes, or eyes with narrow-angle glaucoma, instantaneous, permanent iris perforation was produced in all except two. In these two, a second treatment on the following day produced a permanent perforation. Serious complications were encountered in only one patient who received treatment at a greater energy level than we now recommend. In that patient striate keratopathy became apparent, as well as a decrease in vision which has lasted five months. No significant complication was encountered in any eye treated with the currently recommended procedure.

A 14-month prospective study of patients with premature rupture of the membranes was performed. The purpose of the study was to determine the effect of different therapeutic regimens for management of premature rupture of the membranes (PROM) on perinatal morbidity and mortality, as well as on maternal morbidity. Maternal and fetal risk factors and predictive factors in pregnancy outcome were prospectively defined. In patients with PROM whose gestational age was 34 weeks or more, induction within the first 12 hours of membrane rupture resulted in minimal maternal and fetal morbidity and mortality. Patients with gestational age of less than 34 weeks had an improved maternal and fetal outcome if left alone until spontaneous labor or 34 weeks' gestation was reached unless signs of sepsis developed. Respiratory distress syndrome (RDS) was the leading cause of morbidity and mortality in the infants of patients who delivered prematurely due to premature rupture of the membranes. Incidence of fetal infection was significantly less than that of RDS as a cause for fetal morbidity and mortality.

A run to excite nuclear levels via synchrotron radiation was carried out. These experiments used a given configuration to excite the 14-keV 100 nsec state of /sup 57/Fe, and observe the subsequent decay of this state via the emission of conversion electrons. The most significant result is the demonstration that the ''between pulse'' background radiation is at least 10/sup 5/ to 10/sup 6/ less than the pulse intensity. This value was not previously established. (JFP)

The multimodal stress management program discussed in this article was developed in a hospital setting. Refined during the past five years, this intensive six-week course helps employees handle tension on and off the job by teaching them a variety of stress reduction techniques.

The implantation and annealing of the heavy group III p-type dopants in silicon (Ga,In,TL) has received much less attention than boron. However these dopants have a number of specialized applications, and the recent use of indium implantation for high value resistors (l) was part of the motivation for this study.

It has been shown previously that proton bombardment of N or P-type GaAs results in the creation of compensated layers of high resistivity [1]. This effect has been studied in N-type GaAs, using protons ranging in energy from 25 to 300keV and doses from 1010 to 1015 cm-2. The profile of the compensating centers was measured, and from this the rate of removal of the free carriers by the impinging protons was determined as a function of depth. The electrical characteristics of the compensated layers were studied, particularly the resistivity as a function of proton dose and annealing temperature. The optimum dose required to produce the highest resistivity was determined. Some preliminary observations are presented about the annealing behavior of the compensation. Finally, the application of this compensation effect to achieve a semi-insulated gate GaAs field-effect transistor is discussed. In conclusion, proton bombardment results in semi-insulating layers suitable for device application. The characteristics of the field-effect transistors will be improved by using optimized geometries.

A method has been developed for the assay of the odorous attractant of the cockroach, P. americana. The method, called the counterpoint test, employs two matched groups of roaches and provides for a simultaneous titration of standard and unknown. It has a statistical error of +/-40 per cent at a level of significance of 95 per cent.

1. Procedures have been developed for studying quantitatively the response of the male American cockroach to the odorous attractant of the female. 2. The percentage of male roaches responding to extracts of the attractant of the female has been found to vary with the log of the concentration of the attractant throughout a wide range. 3. Adaptation to the olfactory stimulus has been demonstrated. 4. A theory of adaptation is offered.