Rishi: Yājñavalkya-tradition (Śukla-Yajurvedic school attribution; specific ṛṣi not explicitly marked in the given excerpt).
Devata: Savitṛ (with the Vasus as the invoked class through ‘vasoḥ pavitram’).
Chandas: Mixed/prose-like yajus-formula with metrical cadence; not a strict Ṛgvedic metre (yajus).
Samhita Patha (Devanagari)वसो॑ः प॒वित्र॑मसि श॒तधा॑रं॒ वसो॑ः प॒वित्र॑मसि स॒हस्र॑धारम् । दे॒वस्त्वा॑ सवि॒ता पु॑नातु॒ वसो॑ः प॒वित्रे॑ण श॒तधा॑रेण सु॒प्वा काम॑धुक्षः ।
Transliterationvásoḥ pavítram asi śatádhāraṃ vásoḥ pavítram asi sahásradhāram | devás tvā savitā punātu vásoḥ pavítreṇa śatádhāreṇa supvā́ kāmadhúkṣaḥ ||
Translationനീ വസുക്കളുടെ പവിത്രം (ചാലനി) ആകുന്നു—നൂറു ധാരകളുള്ളത്; നീ വസുക്കളുടെ പവിത്രം ആകുന്നു—ആയിരം ധാരകളുള്ളത്. ദേവനായ സവിതൃ വസുക്കളുടെ പവിത്രത്താൽ, നൂറു-ധാരയുള്ള പവിത്രത്താൽ നിന്നെ ശുദ്ധീകരിക്കട്ടെ; ഹേ സുപവിത്ര, ആഗ്രഹങ്ങളെ ദോഹിച്ച് നൽകുന്നവനേ!
Padapatha (Word Analysis)वसोः । पवित्रम् । असि । शत-धारम् । वसोः । पवित्रम् । असि । सहस्र-धारम् । देवः । त्वा । सविता । पुनातु । वसोः । पवित्रेण । शत-धारेण । सुप्वाः । काम-धुक्षः ।
Word by Wordवसोःof Vasu / of the Vasus शतधारम्having a hundred streams वसोःof Vasu / of the Vasus सहस्रधारम्having a thousand streams वसोःof Vasu / of the Vasus पवित्रेणwith the purifier (filter) शतधारेणwith the hundred-streamed (one) सुप्वाwell (in a purifying way) कामधुक्षःwish-yielding; granting desires 
Viniyoga (Ritual Application)