. American X-ray journal . gs. 7 and 8,fitted with four cathodes of inch, , 1 inch, and inch diameter re-spectively. They all have the same ra-dius of curvature, i. e., inch, and 3o8 THE AMERICA AT X-RAY JOURNAL. all focus upon the same point on theanticathode, which is mounted upon aspindle, so that it can be turned roundso as to face any one of them. Withthis tube, as with the last shown, it isfound that the larger the cathode theless penetrative, and the smaller thecathode the more penetrative are therays produced. There appears to be noadvantage in employing extra la
. American X-ray journal . gs. 7 and 8,fitted with four cathodes of inch, , 1 inch, and inch diameter re-spectively. They all have the same ra-dius of curvature, i. e., inch, and 3o8 THE AMERICA AT X-RAY JOURNAL. all focus upon the same point on theanticathode, which is mounted upon aspindle, so that it can be turned roundso as to face any one of them. Withthis tube, as with the last shown, it isfound that the larger the cathode theless penetrative, and the smaller thecathode the more penetrative are therays produced. There appears to be noadvantage in employing extra large ca-thodes, even when the exhaustion ismade to suit them. Experiments withvarious sizes, from 2 5 inches diameterdown to inch diameter, go to showthat even with the full power of a 10-inch induction coil with mercury break,there is no advantage in making the ca-thodes more than inch use with a 10-inch coil they shouldnot be smaller than about inch di-ameter, as, if less than this, they are. fig. 9. apt to become overheated, and theirsurface and form destroyed. For usewith 6-inch and smaller coils, very smallcathodes, even down to incn di-ameter, will work very well, and will notrequire such high exhaustion as largerones. Small cathodes should, in pro-portion, have a less focal length thanlarge ones for the best results. Proba-bly, a good average size for ordinarywork is about inch diameter, inch radius of curvature. It is im-portant for the best work that the sur-face should be well polished, and to beof quite even curvature. Another simple and, in my opinion,altogether superior form of adjustabletube, which has the advantage of a fixedpoint of origin for the x-rays, and whichhas a great range of adjustment, de-pends for its action upon the fact that the resistance of the tube and the pene-trative value of the x-rays that it gener-ates can be greatly varied by alteringthe radius of the annular space betweenthe edge of the ca
Size: 3167px × 789px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectrad, booksubjectxrays
