9 Scientific apparatus and instruments, namely, photon-detecting instruments, low-noise amplifiers, noise discriminators, light-detecting instruments, electron tubes, radiation detectors, radiation-measuring instruments, voltage regulators, voltage stabilizers, calibration sensors; electron multipliers; photomultipliers; [ thermionic devices, namely, thermionic tubes, thermionic valves; ] sensors for detecting light or other electromagnetic radiation scintillators; electronic controllers equipment for all or any of the foregoing; voltage dividers; housings for electronic apparatus, instruments and equipment; housings for electrical apparatus, instruments and equipment; [ computer housings; ] housings for electrical measuring apparatus; amplifiers; amplifier-discriminators; counters and counting instruments for use in photon counting; electronic counters use in photon counting; electrical and electronic counter-timers and photon-counting modules; connection cables; [ computer cables; ] coaxial cables; [ electric data transmission cables; electric cables; ] electronic cables; [ fibre-optic cables; electrical sockets; ] electric power supply units; laboratory power supply apparatus, namely, electrical power suppliers for use in laboratories; portable power supply apparatus, namely, portable electrical power suppliers; electronic circuits; switching circuits, namely, electric switching circuits; magnetic shields, namely, shields for use in protecting photomultiplier tubes and scintillation counting tubes from external magnetic fields; [ oscilloscopes; ] electrical conductors; [ electrical conduits; ] electrical connectors; electric connector boxes; electric sockets; [ coaxial electrical connectors; ] electrical connectors for use with electronic circuits, [ fibre-optics ] and circuit boards; [ electric cable connectors, coaxial cable connectors; ] temperature controlling apparatus for use with all or any of the foregoing; computer software for use in operating and controlling photomultipliers, light-detection, photon-detection, photon-counting and calibration machines and systems; downloadable computer programs for use in operating and controlling photomultipliers, light-detection, photon-detection, photon-counting and calibration machines and systems; downloadable electronic publications, namely, brochures, [ leaflets, pamphlets, flyers, ] data sheets, [ books, ] booklets, guides, manuals, [ posters, magazines, journals, periodicals, newsletters, ] reports, information cards, photographs, instructional and teaching materials in the fields of light-detection, photomultipliers, photon-detection, photon-counting and calibration