468
TABLES
.
TABLE 11.—ELÉCTRONs—RANGE AND SPECIF10 IONIZATION
R = range in centimeters in air at 760 millimeters and 15° C.
R’ = range in aluminum in terms of the mass in grams per square centimeter
required to stop the electrons.
6 = v/c‘, :) = velocity of electrons, c = velocity of light.
.
__
V = energy
of electrons in kilovolts.
_
'
.
v =
number of ion pairs (primary and secondary) produced per centimeter of
’
path of electrons in air.
5
V
R’
R
,,
.
'
kilovolts
gm./cm2.
cm.
.
_
.
0.24
0.15
.
7700
0.10
'
2.55
000005
0.04
2100
='0.20
0.00027
0.23
1000
0.30
24.7
00012
1.0
_
400
0.40
46.6
0.0041
250
0.50
79.1
0.0087
7.3
180
'
0.60
127.8
00215
17.9
130
0.70
.
204.7
_
0.045
37.5
95
'
0.80
341.0
0.10
83.0
70
0.90
662.
.
0.26
217.
50,
_
0.95
1127.
0.525
437.
45
.
0.98
2058.
1.03
860.
0.99
3114.
1.57 '
1300.
41
From Radioactivité, by Madame P. Curie, p 294, published by Hermann & Co., Paris, 1935.
’
TABLE '12.——AMORPT10N COEFFICIENTS or ALUMINUM ron BETA RAYS
'
_
Emitting
p
_
Emitting
#
Emitting
,u
'
Substance
(cm. “l)
.
Substance
(cm. '1)
Substance
_
(cm. »“1)
UX12.………
Ï 460
RaD.....……
5500
‘
MsTh2,….…
40t020
UX2……..….
18
RaE..…….…
45.5
RaTh..….…..
420
‘
UY_.…..……
…300
-……….…Pa.
126‘_
ThB..….……
153
‘
312
‘RAC.....…….
175
Th (C+C”)... 21.6; 14.4
RaBB..………. 890;80;13
AcB......…..
1000
ÙRa (C+C’)...…
50; 13
Ac (C+C”)..…
29
.
From Radioactivité, by Madame P. Curie, p: 280, published by Hermann & Co., Paris, 1935.
_