Etching time (min)

Track density (No/mm2)

Time of exposure to alpha source

(10 sec)

(20 sec)

(30 sec)

10

654

1124

1453

20

670

1247

1466

30

830

1206

1683

40

708

1057

1630

Average

715.5

1158.5

1558

Max

830

1247

1683