( Geiger ( ( counter ( ( An instrument ) ( used ( to ( ( measure ( radioactivity ( -LRB- ( ( ( e.g. , ) ( that ( which ( emanates ( from ( certain minerals ) ) ) ) ) ) -RRB- ) ) ) ) ( by ( means ( of ( a ( Geiger ( - ( Mueller tube ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Geiger)) (VP (VBP counter) (NP (NP (DT An) (NN instrument)) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NP (NN radioactivity)) (PRN (-LRB- -LRB-) (NP (NP (NNP e.g.)) (, ,) (NP (NP (DT that)) (SBAR (WHNP (WDT which)) (S (VP (VBZ emanates) (PP (IN from) (NP (JJ certain) (NNS minerals)))))))) (-RRB- -RRB-))) (PP (IN by) (NP (NP (NNS means)) (PP (IN of) (NP (DT a) (NNP Geiger) (: -) (NNP Mueller) (NNP tube))))))))))) (. .)))
Geiger counter An instrument used to measure radioactivity (e.g., that which emanates from certain minerals) by means of a Geiger- Mueller tube.
(ROOT (S (NP (NP (DT The) (`` `) (NN counting) ('' ') (NN instrument)) (NP (NN geiger) (NN counter))) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB measure) (NP (NN radioactivity))))))) (. .)))