A factory uses a beta source and a detector to check cardboard packaging blanks moving on a conveyor.
A blank is accepted when the corrected count rate is between 600 and 660 counts per minute.
A pivoting flap sends acceptable blanks straight ahead. It turns left to send a blank that is too thick into one reject bin and turns right to send a blank that is too thin into another reject bin.
The detector records the following data for one blank.
| Measurement | Number of counts in 40 s |
|---|---|
| source and blank in position | 394 |
| background with the source shielded | 14 |
Calculate the corrected count rate for the blank. Give your answer in counts per minute.
Explain how the control system should respond to this blank.