What is the brightness gain of an image intensifier with a 12-inch input phosphor and a flux gain of 100?

To determine the brightness gain of an image intensifier, you calculate it using the formula:

Brightness Gain = Input Phosphor Area × Flux Gain

In this scenario, we need to find the area of the input phosphor. Given that the input phosphor is 12 inches in diameter, we can first calculate its radius:

Radius = Diameter / 2 = 12 inches / 2 = 6 inches.

Next, we convert inches to centimeters, knowing that 1 inch is approximately 2.54 cm:

6 inches × 2.54 cm/inch = 15.24 cm.

The area (A) of a circle is calculated using the formula:

A = π × r².

Now, using the converted radius in centimeters:

A = π × (15.24 cm)² ≈ π × 232.59 cm² ≈ 731.60 cm².

Next, we can compute the brightness gain. With the area of the input phosphor determined and the flux gain provided as 100, the brightness gain will be:

Brightness Gain = Input Phosphor Area × Flux Gain
= 731.60 cm² × 100
= 73,160.

However, this number seems