( ( To ( decrease ( the ( dark current ) ) ) ) ( , ( ( ( far infrared ) detectors ) ( ( must ( be ( cooled ( ( ( ( to ( liquid nitrogen ) ) or ) even ) ( to ( liquid ( helium temperatures ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (TO To) (VP (VB decrease) (NP (DT the) (JJ dark) (NN current))))) (, ,) (NP (ADJP (RB far) (JJ infrared)) (NNS detectors)) (VP (MD must) (VP (VB be) (VP (VBN cooled) (PP (PP (TO to) (NP (JJ liquid) (NN nitrogen))) (CC or) (RB even) (PP (TO to) (NP (JJ liquid) (NNP helium) (NNS temperatures))))))) (. .)))
To decrease the dark current, far infrared detectors must be cooled to liquid nitrogen or even to liquid helium temperatures.
(ROOT (S (NP (NN Liquid) (NN nitrogen)) (VP (VBZ is) (VP (VBN used) (PP (IN for) (NP (NP (VBG cooling) (NNS detectors)) (PP (IN of) (NP (JJ infrared) (NNS telescopes))))))) (. .)))