NEW
EQUIPMENT APPARATUS INSTRUMENTS
PRODUCTS
Research Microscopes Feature "Push-Button" Illumination
Varian Associates' E-P-R spectrometer Model V-4500
E-P-R Spectrometer Available The Instrument Division of Varian Associates has recently announced regular commercial production of an Electron Paramagnetic Resonance (E-P-R) spectrometer of high sensitivity. A basic laboratory research instrument, the Model V-4500 is applicable in the fields of chemistry, physics, and biology. I t is said to be capable of inducing and observing E-P-R signals from substances having a resultant electronic magnetic moment. E-P-R spectroscopy involves the use of the magnetic properties of unpaired electrons in determining chemical structure and bonding characteristics. Where an unpaired electron is present, a strong magnetic field will apply a torque to the axis of the resultant magnetic moment. The resulting rate of gyroscopic precession will distinguish the particular atom and its environment. An electron, however, may have not only an intrinsic magnetic moment along its own spin axis, but also one relative to its circulation in an atomic orbit. The V-4500 E-P-R spectrometer measures the counter-effects on an applied radio-frequency magnetic field, and produces a graphic record with characteristic resonant peaks, Varian says. We are told that use of this spectrometer can lead to identification of odd
molecules and free radicals, bi-radicals, triplet electronic states, radiation damage sites, transition element ions, impurities in semi-conductors, and color centers. The V-4500 is also helpful in determination of chemical kinetics, electron exchange rates, molecular structures, microscopic electrostatic fields at transition element ion sites, characteristics of conduction band and trapped electrons in metals and semi-conductors, and free radical constituents and kinetics in biochemical reactions. Among the items comprising the equipment are a sample cavity, connecting wave guide, microwave bridge with klystron oscillator, klystron power supply, phase-sensitive detector, oscilloscope, graphic recorder, and control console with writing surface. The associated magnet system, which is vitally important, is available in several choices. Several components of the E-P-R spectrometer, namely those relating to detection and display, are identical to those used in the Varian N-M-R spectrometer. This compatibility is cited by the company as an added feature of the instrument, since converting one type to the other is less expensive than purchase of completely separate E-P-R and N-M-R spectrometers. 1
A nevy series of research microscopes, known as the " R " series, is now available from the Bausch & Lomb Optical Co. Many of the firm's standard design features are incorporated into the new line, with several major developments added. Most important of the improvements, according to the company, is an achromatic variable focus condenser which provides "push-button" illumination. Unusually large lenses in the condenser, a graduated numerical aperture scale, and a knurled ring for setting the lens system are reported to provide the speed, accuracy, and ease of the new illumination system's operation. Other features cited by the company include: eyepieces fitted with rubber inserts to protect user's glasses; a control location which enables the operator to make adjustments without raising his hand from the table; concentric coarse and fine focusing knobs for the substage; a cast iron microscope arm for increased rigidity; and a graduated pupillary distance scale on the binocular eyepiece. 2 New Series of Oil Baths The Magni-Whirl oil baths, offered by the Blue M Electric Co., are designed for general and analytical laboratory procedures, as well as \
