Battery setup to power UVC bulb with 12 V DC at 1 A
Here's a schematic that is not re-triggerable but can be used as a 2 second timed lamp circuit. I've included a D45H11 because they are in TO-220 packages, are cheap, available everywhere, and can deliver a lot of current while maintaining a decent \$\beta\$.







simulate this circuit &ndash; Schematic created using CircuitLab

Feel free to lower the value of \$R_2\$ a little, if you want to supply more base current into \$Q_1\$ (if the lamp needs a lot of current then the base needs more drive current.)

Adding re-triggerability requires the addition of two diodes. But I didn't add them since you'd prefer it without that feature.

Also note that although the schematic shows a bulb/lamp, I really mean your entire lamp + circuit to go there. I don't know how long your HV circuit itself takes to stabilize and fire the lamp. But you can adjust the timing as needed.

The timing is determined by the two parts in the dashed box; \$C_1\$ and \$R_3\$. Adjust these a little to adjust the timing.

You can also use a BAV99 instead of \$D_1\$ and \$D_2\$.