(physics) gamma ray

speciality/specialty; subject of study; subject of expertise; area of interest; profession

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

a piece of research, a study, investigation

to research, to study

specialist; expert

expert, special

academy (specialized school), vocational school