EXPERIMENTAL OUTPUT LEVELS —

4. 4.1 Measured Sensitivities

The following sensitivities are obtained directly from measured signal and flux levels. The units for d-c sensitivity are the usual. The counting sensitivity is given for three values of gamma flux background.

a. D-C Sensitivity

image395

D-C Sensitivity (Neutron) D-C Sensitivity (Gamma)

Counter

1. 9 x

10 a

= 2. 9 x 10"16 a/nv

9.

4 x 10" a ■ ■

= 3. 2 x 10"13 a/R/h

No. 1

6. 6 x

109 nv

2.

9 x 106 R/h

Counter

1. 9 x

10"6 a

= 2. 9 x 10"16 a/nv

1.

2 x 10"6 a

= 4. 1 x 10"13 a/R/h

No. 2

6. 6 x

10‘9nv

2.

9 x 106 R/h

Counter 1- 00 x 104 cps = L52xl0’3 1.22 >: 106 cps = 0. 68 x 10’3

No — 1 6.6 x 106 nv 1.80 > 109 nv

Discriminator setting = 3.5 (arbitrary scale), 40 feet of 50-ohm in-core cable, 85 feet of standard 75-ohm cable (RG-6A/U) terminated in 75 ohms.

-18[3]

-18*

-18[4] [5]

•19*

-18*

-19**

image396 image397 image398

c. Mean Square Outputs of Detector Assemblies

Подпись: 3. 4 x 10Подпись: not testedOut-Of — Core Chamber NA04

NOTE 1. The mean square output/cycle below breakpoint

2

due to ionic mobility in the < V > distribution curve of the ion produced signal is four-times that above the break­point. All sensitivities quoted are below this breakpoint.

NOTE 2. The fraction of the applied field through which the charge falls is about one-half if only electron motion is contributing to the signal; i. e., if the bandpass of the circuit lies above the breakpoint due to ion transit time in the power spectral density curve. It is unity if both electron and ion motion contribute to the signal; i. e., if the bandpass of the circuit lies below the breakpoint due to ion transit time in the power spectral density curve. .

image401

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