we EE ah aba ee wat Dee als ea alla Eade ine
218
im
qT
0.12
7
Hest
Ne
+
0.11 f—
M2/C
|
Ary
No.
He(He) wis
0.10 _ He
+
HoT
No
CHa
+
BFy,
CaNo
+.PHs
' + kycatt
H
2
10
|
18
4-3
iCa tio
xe
4-2
+%ers
cyCgHiz,
,NCgHis
++
C5H
+ nCgHi2
6 CO2 4
4{CHs}20
CH30H
+?
nCeHio
++
CeHsOH (cH4)0C0
+
0.09
rT
Kr
neoCa hyo
4thC2He
CoH,
T
+
CsHg
0
402
co
4
CF4
In ¢j
44 - \
nCrHig
C/M? - in cj = In (2/a)*
aL
26
Lt
36
42
°
ee
48
54
58
n = TOTAL NUMBER OF ELECTRONS
Fic. 169.—Experimental results for M2/C
of 0.01. Points of that or better accuracy are given unit
weight in the LS solution; points of less accuracy are
given appropriately smaller weight. In some cases, the
RAIS deviation turns out to be very nearly 0.01; in
others, us much as 215 times as great. The difference
cannot be attributed to genuinely randomeffects; we
attribute it to variations in e, which have been treated
as systematic crror. We conclude that the true random
error in our experiments can be estimated reasonably
well by multiplying the cocfficients from the LS solution
by 0.01. It is the random error so obtained that should
be added to the systematic errors indicated in Table 79.
The coefficients vary from experiment to experiment,
since they depend upon the number and distribution of
the data points. They lead to magnitudes of AC/C
ranging from 0.002 to 0.012. For A(Af?/C), the magnitudes range from 0.0015 to 0.004.
SUMMARY
All the results obtained to date are summarized
graphically in Figures 168 and 169. With the aid of
values taken from these plots and Figure 166, cross
sections at any energy where the Bethe formula is
applicable can be obtained by simple multiplication.
REFERENCE
1. Rieke, F. F. and Prepejchae, William. Argonne National
Laboratory Radiological Physics Division Annual Report,
July 1967-June 1968. ANL-7489, p. 99.
TABLES OF ABSORPTION CROSS SECTIONS, PHOTOIONIZATION YIELDS,
AND PHOTOIONIZATION CROSS SECTIONS FOR SEVERAL GASES
J.C. Person and P,P. Nicole
Tables of absorption cross sections, photoionization yields,
and photoionization cross sections are presented for acetylene,
propyne, propene, methanol, ethanol, and methyl bromide, and
also for the perdeuterated analogues of these gases. For each
gas. the data are reported for energies ranging from a value
belowthe ionization potential up to 1L.78 eV.
This report gives the data in tabular form forresults
that will be presented and discussed’ elsewhere. The
data were collected using an experimental apparatus
and procedure that were essentially the same as previ-
ously described." ?) The data for acetylene, propyne,
propene, methanol, ethanol, and methyl bromide are
labelled with a subscript H; while the data for the per-
deuterated analogues of these gases are labelled with a
subscript D. Each table gives the wavelength and the
energy, #, of the monochromatic (~1 A bandwidth)
exciting light. The absorption cross sections, 7, were
determined from measurements using ” gas pressures;
and the deviations from a weighted least squares fit of
the data to Beer’s law were used to estimate the 90%
confidence limits as {¢ — 6c) to (o + éc). In addition
to this statistical error, the systematie error in the ¢