At a particular position, a worker receives a radiation dose of 3 μSv3\ \mu\mathrm{Sv}3 μSv each minute. A screen reduces this rate to one-third. The worker spends 6 minutes behind the screen. What dose does the worker receive?
18 μSv18\ \mu\mathrm{Sv}18 μSv
6 μSv6\ \mu\mathrm{Sv}6 μSv
2 μSv2\ \mu\mathrm{Sv}2 μSv
9 μSv9\ \mu\mathrm{Sv}9 μSv