|
1. |
WAVE LENGTHS, EQUIVALENT WIDTHS, AND LINE PROFILES IN THE SPECTRUM OF THE STAR H.D. 190073 |
|
Canadian Journal of Research,
Volume 27a,
Issue 5,
1949,
Page 169-190
C. S. Beals,
Miriam S. Burland,
Preview
|
PDF (1026KB)
|
|
摘要:
With the aid of long exposures (18 and 25 hr. respectively) the spectrum of H.D. 190073 in the ordinary region has been photographed with dispersions of 7.3 to 15.2 Å per mm. The resulting spectrograms revealed approximately 100 stellar lines not observed with single-prism dispersion as well as indicating more clearly the structure of a number of complex line profiles. Wave lengths, identifications, and equivalent widths are listed for all observed lines, and a number of the more interesting line profiles are illustrated. The interpretation of line profiles is discussed and it is pointed out that the presence of asymmetrical hydrogen lines is an indication of a shell of relatively small diameter.
ISSN:1923-4287
DOI:10.1139/cjr49a-018
出版商:NRC Research Press
年代:1949
数据来源: NRC
|
2. |
DESIGN OF GRID IONIZATION CHAMBERS |
|
Canadian Journal of Research,
Volume 27a,
Issue 5,
1949,
Page 191-206
O. Bunemann,
T. E. Cranshaw,
J. A. Harvey,
Preview
|
PDF (684KB)
|
|
摘要:
Conformal representation theory is applied to a grid ionization chamber having plane parallel electrodes to give formulas useful in design. Expressions are obtained for the inefficiency of grid shielding of the electron collector, the spread of pulse size caused by the induced effect of positive ions, and the proportion of electrons collected by the grid. The theory was verified by experiment. The width of the polonium α-particle line at half-maximum was reduced to 50 kev. or about 1% of the energy by the use of a suitable grid and operating voltages. The corresponding standard deviation from all causes was 22 kev., made up of 2 kev. resulting from induced effect of positive ions, about 17 kev. from noise in the amplifier, and 14 kev. from straggling of ionization, thickness of source, and other effects. The spread caused by positive ions can therefore be almost completely eliminated by a grid.
ISSN:1923-4287
DOI:10.1139/cjr49a-019
出版商:NRC Research Press
年代:1949
数据来源: NRC
|
|