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A continuous wave photofragment spectrometer is described which can investigate photodissociative reactions by measuring angular dependent mass spectra of the recoiling photofragments. The three‐state differentially pumped vacuum system consists of three mutually orthogonal axes: a polarized light axis (high pressure Hg–Xe), a molecular beam axis, and a quadrupole mass filter axis. The electric vector of the polarized light is rotated by a stepper motor (1‐rpm). The photofragment signal from the tuned amplifier is lock‐in detected and displayed on a strip chart recorder. Various inorganic filter solutions are employed in order to suitably excite the desired transitions of molecules with favorable absorption coefficients (∼100 1 mole−1 cm−1) in the spectral range of the excitation source. Signal averaging is accomplished using long lock‐in amplifier time constants as well as multichannel scaling. The relative merits of cw photofragment spectroscopy are also discussed with particular reference to the photod...

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RENAL artery aneurysms, once considered rare, are being recognized with increasing frequency. Garritano, 1 in 1957, collected 175 cases dating back to 1770. 2 In the decade since 1957, approximately 170 additional cases of renal artery aneurysm have been reported, bringing the total to 345. With the expanded use of aortography and selective renal angiography in the evaluation of patients with vascular disease and suspected renovascular hypertension, the number of cases will undoubtedly continue to increase. Aneurysms of the renal artery are said to constitute 1% of all aneurysms. 3 Based on autopsy studies the incidence in the general population ranges from 1 in 7,000 4 to 1 in 11,000. 2 A study of hypertensive patients reveals a considerably higher incidence of 1 in 112. 5 Schwartz and White 6 reported an incidence of 15 in 154 based on renal arteriograms made in unselected autopsy specimens. Renal artery aneurysms are