Make a Radiation Hardened Quine
Gol>&lt;>, 49 45 bytes

&lt;&lt;H~Kla}\`q%2l}}ss2"&lt;\
&lt;&lt;H~Kla}\`q%2l}}ss2"&lt;\


Try it online!

Verification!

I did this in Gol>&lt;> rather than >&lt;> because the former has the handy K operator that copies the top n items on the stack, which makes duplicating the clean copy of the source code easier.

Explanation:

This works by having two copies of the executing code, and redirecting to the second one if the first is damaged. This fails when the last \ or the middle newline is removed, both of which are compensated for later.

&lt;&lt;                       Redirect left 
                    &lt;\  Switch to other source code if this line is irradiated
                   "     Push source with wrapping string literal
                ss2      Push quote
              }}         Move "&lt; to end
          q%2l           If the length of the stack is not right
        \`               Push an extra \
       }                 Move the \ to the end
      a                  Newline
    Kl                   Duplicate the stack
   ~                     Pop the extra newline
  H                      Halt and print stack