Physics and Engineering of Radiation Detection

2.1. Some Basic Concepts and Terminologies 73

Z

0 20 40 60 80 100

Radiation Length

0

10

20

30

40

50

Z

0 20 40 60 80 100

Relative Difference (%)^15

20

25

30

35

40

45

Figure 2.1.2: Upper plot shows the radiation

lengths ing/cm^2 computed from equations 2.1.14

(solid line) and 2.1.16 (dashed line). The lower

plots shows the relative error in the values com-

puted from equation 2.1.16 with respect to the

ones computed from equation 2.1.14.

of carbon and oxygen.

XC 0 =

(716.4)(12.01)

6(6 + 1) ln(287/

√

6)

=43. 0 gcm−^1

XO 0 =

(716.4)(16.0)

8(8 + 1) ln(287/

√

8)

=34. 46 gcm−^1

Now we need to calculate the weight fractions of carbon and oxygen inCO 2 ,

which can be done as follows.

w 1 =

12. 01

12 .01 + 16.0+16. 0

=0. 2730

w 2 =

16. 0

12 .01 + 16.0+16. 0

=0. 3635

w 3 = w 2.

Where the subscript 1 ofwrefers to carbon whilew 2 andw 3 represent the

weight fractions of the two oxygen atoms inCO 2.