— photornultiplier tubes with a pboiocatbode which gives a current of at least 10 microamperes per lumen and in which the average amplification is greater than 105, and any other types of electric multiplier activated by positive ions;
— feadáin fóta-iolraitheoirí le fótachatóid a thugann sruth 10 mhic-ri-aimpéar ar a laghad an lúman agus inar mó ná 105 an meá- naimpliú, agus iolraitheoir leictreach d'aon chineál eile a ghníomhachtaítear le hiain dhearfacha;