Obviously death sentences cannot deter bombers who believe they will
go to heaven, then a easy & cheap way to deter them is to thwart their
reaching / staying in heaven, + confiscation of their assets.
Your govnmnt can empower police / coroner to *, if bombers' bodies
can be found / re-assembled.
Costly ways must be x-ray scanning / filming of bags, in train stations
& buses ( when x-ray machines can be small enough ).