220
9.
X-RAYS
for calcite
is 3.029
angstroms.
Compare your values With
accepted values.
Âddz‘z‘ioml Experiments.——2. Set the crystal and chamber for
any one wave-length, say
0.5 angstrom, in the more intense por4
_
tion of the continuous radiation.
The wave—length is determined
as
in (1) above, and the corresponding frequency calculated;
call it vmax.
Plot a curve of the intensity of this x-ray for various
voltages up
to 60 kilovolts across the tube. The voltages are
-
peak values and may be measured With a spark gap.
(See chapter
19.)
Full wave rectication must be used in the supply in order
that the spark gap voltmeter Will read correctly. The plot Will
show a straight line, called an imc/woman“, whose intercept (at: V)
on the voltage axis may be used With vmax in the Duane—Hunt law
'
(equation 4—22) to compute /1/ e.
'
3. Plot the intensity of the Ka1 line of molybdenum (the one
—
of shorter wave-length, for Which 0 is smaller) for various voltages
up
to 60 kilovolts across the tube.
Note the difference between,
this curve and the isochromat.
The intercept on the voltage axis’
corresponds to the frequency of the absorption limit of the
_
=
K series of molybdenum (0.618 angstrom, not that of the line
whose wave-length is 0.707 angstrom). Although not so satis—
'
factory a method as (2), it can be used to compute /z/e (equation'
4—22).
'
4. Measure the K absorption limit of tin by inserting a sheet
of thickness 0.08 millimeter in the path of the X-rays and plotting
_
the spectrum curve as described in (1) above.
Only that region
near
the-critical limit need be plotted. The correct value13
…
_
0.424 angstrom.
_
:
'
REFERENCES
'
translation by Stanton. Science, 3, 227 and 726 (1896).
'
'
‘
Ï
Ï2Â- W. D. Coolidge‘, Phys. Rev., 2, 409 (1913).
'
…/
'
A, page ”16.
,
-'
Ÿ
_
General reference A,—page 237.
'
,
'
_
5AHCOmpton;
2.1, 207, 483, and 22: 409 (1923)9; '
Ÿ
64 C G
SCC-; A77; 247 (1906)Â
.
;
_
Rev.,"25, 235 (1925).
;
J
'
‘
"
: î»5814%*A-:fH-r—ïCo’mptèn, Phil: Mag?
(“l-9123):
= :
‘
“
f
‘
,
;Ï_
9AH
fL. Dc‘5an,
Acad. Sci., “II, 59 85 (1925)‘
…
10WH Bragg—‘
.Smzç. -f":Vçlunie“ I, Macmaiiap(1%4)
9.
X-RAYS
for calcite
is 3.029
angstroms.
Compare your values With
accepted values.
Âddz‘z‘ioml Experiments.——2. Set the crystal and chamber for
any one wave-length, say
0.5 angstrom, in the more intense por4
_
tion of the continuous radiation.
The wave—length is determined
as
in (1) above, and the corresponding frequency calculated;
call it vmax.
Plot a curve of the intensity of this x-ray for various
voltages up
to 60 kilovolts across the tube. The voltages are
-
peak values and may be measured With a spark gap.
(See chapter
19.)
Full wave rectication must be used in the supply in order
that the spark gap voltmeter Will read correctly. The plot Will
show a straight line, called an imc/woman“, whose intercept (at: V)
on the voltage axis may be used With vmax in the Duane—Hunt law
'
(equation 4—22) to compute /1/ e.
'
3. Plot the intensity of the Ka1 line of molybdenum (the one
—
of shorter wave-length, for Which 0 is smaller) for various voltages
up
to 60 kilovolts across the tube.
Note the difference between,
this curve and the isochromat.
The intercept on the voltage axis’
corresponds to the frequency of the absorption limit of the
_
=
K series of molybdenum (0.618 angstrom, not that of the line
whose wave-length is 0.707 angstrom). Although not so satis—
'
factory a method as (2), it can be used to compute /z/e (equation'
4—22).
'
4. Measure the K absorption limit of tin by inserting a sheet
of thickness 0.08 millimeter in the path of the X-rays and plotting
_
the spectrum curve as described in (1) above.
Only that region
near
the-critical limit need be plotted. The correct value13
…
_
0.424 angstrom.
_
:
'
REFERENCES
'
translation by Stanton. Science, 3, 227 and 726 (1896).
'
'
‘
Ï
Ï2Â- W. D. Coolidge‘, Phys. Rev., 2, 409 (1913).
'
…/
'
A, page ”16.
,
-'
Ÿ
_
General reference A,—page 237.
'
,
'
_
5AHCOmpton;
2.1, 207, 483, and 22: 409 (1923)9; '
Ÿ
64 C G
SCC-; A77; 247 (1906)Â
.
;
_
Rev.,"25, 235 (1925).
;
J
'
‘
"
: î»5814%*A-:fH-r—ïCo’mptèn, Phil: Mag?
(“l-9123):
= :
‘
“
f
‘
,
;Ï_
9AH
fL. Dc‘5an,
Acad. Sci., “II, 59 85 (1925)‘
…
10WH Bragg—‘
.Smzç. -f":Vçlunie“ I, Macmaiiap(1%4)