File:American quarterly of roentgenology (1911) (14733945726).jpg

Identifier: americanquarterl03amer (find matches)
Title: American quarterly of roentgenology
Year: 1911 (1910s)
Authors: American Roentgen Ray Society
Subjects: Nuclear Medicine Radiography Radiology Radiology
Publisher: Pittsburgh : American Roentgen Ray Society
Contributing Library: Francis A. Countway Library of Medicine
Digitizing Sponsor: Open Knowledge Commons and the National Endowment for the Humanities

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Fig. 5. A very poor tube (six-inch tube)showing movement of the focal point in bothdirections, but more in the transverse. Ben-oist 6; 40 m. a. Fig. 7. A very poor tube (eight-inch bulb)showing movement of the focal point in alldirections. Benoist 6; 45 m. a. Fig. 6. Good tube (six-inch bulb). Benoist6; 45 m. a. Fig. 8. A poor tube (six-inch bulb). Seethe double transverse lines indicating move-ment of the focal point in the longitudinal di-rection. Benoist 7; 35 m. a. 20 American Quarterly of Roentgenology
Text Appearing After Image:
Fig. 0. Very good tube (six-inch bulb) show-ing a slight movement. Benoist 6; 40 m. a. Fig.oist 5 u. A poor tube (seven-inch bulb).35 m. a. Ben- Fig. io. A very poor tube (seven-inch bulb).Notice that the shadows of the fuse wire arepractically obliterated. Fig.m. a. 12. A very good tube. Benoist 5; 45 In all tests the focal point was 18 inches from the plate, and in each instance the tube was firsttested until it would take the full current smoothly. Pfahler: Variability of Focus Point 21 might also be inferred that a low tube would have a morestable focus, but neither the low nor the high are likely to bestable. In fact, I believe that the stability of the focus has noconnection with the vacuum, although most of the good tubesregister about Benoist 6. On the other hand, many tubesmay register Benoist 6 and still be miserable tubes. I have been especially impressed with the striking vari-ation in so short a period of time. I noted it even in my high-est priced imported tube to a mode

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