Stick with the TV, It's just electrons (Beta radiation), has a range of about 10cm in air, quite safe.
Cut the back off the CRT tube carefully and square, prepare it to take a gasket, it's really thick glass. Onto the front of that attach a metal tube, with a chamber at the end with an observation window and access door on the side. The tube should end with a phosphorus screen so you can see the aim.
Pull a vacuum on the whole ensemble and use the existing coils in the back of the CRT to aim with a little control circuitry (I can help you with that part).
Now you can play with adding accelerator coil/s in the metal tube to make the beam even faster, and put things in the observation chamber to bombard them with electrons.
Edit:
I'm not sure what bombarding stiff with electrons can achieve, maybe etching? A program in the control circuit could make it a digital engraver.