Proportional region

A proportional counter is a detector that operates in the proportional region. 

A proportional counter is a detector which operates in the proportional region, as shown in Figure 6. Figure 7 illustrates a simplified proportional counter circuit. 

To be able to detect a single particle, the number of ions produced must be increased. As voltage is increased into the proportional region, the primary ions acquire enough energy to cause secondary ionizations (gas amplification) and increase the charge collected. These secondary ionizations may cause further ionization. 

In this region, there is a linear relationship between the number of ion pairs collected and applied voltage. A charge amplification of 104 can be obtained in the proportional region. By proper functional arrangements, modifications, and biasing, the proportional counter can be used to detect alpha, beta, gamma, or neutron radiation in mixed radiation fields. 

Varying the detector voltage within the proportional region increases or decreases the gas amplification factor. 

It may be seen from the proportional region of Fig. 1 that only a small fraction, about 1/70, of the DON added to the enzyme becomes covalently bound. Further analysis of this phenomenon has shown that glutaminase catalyzes the hydrolytic cleavage of the ketone and that the rate of this reaction is 70 times that of the irreversible inactivation of the enzyme. Once alkylation of all reactive sites is complete, the further catalytic hydrolysis of DON is totally blocked. 

In the proportional region, the average number of ion-electron pairs collected is given by... 

Shear modulus (G, modulus of rigidity) n. The ratio of shear stress to shear strain within the proportional limit of a material. If the material exhibits no proportional region, a secant modulus is used. 

Beyond the Elastic Limit (Beyond the Proportional Region)... 

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