ARETUSA is an Advanced Research Equipment for fasT Ultraweak lumineScence Analysis developed ad LNS. This set-up allows to perform accurate and realiable Delayed Luminescence (DL) measurements. Infact it  is a highly sensitive equipment able to detect single photons with a very low background signal. It presents a high  efficiency in collecting the luminescence originating from samples. The samples are excited by a Nitrogen Laser source (Laser Photonics LN 230C; wavelength 337nm, pulse-width 5ns, energy 100±5µJ/pulse). The laser light is sent to  the sample through one of the two branches of a bifurcated fiber bundle and the re-emitted photons are collected by the other one. To detect the emitted photons in  the wavelength range 300-800 nm, a multi-alkali photomultiplier tube (Hamamatsu R7206-01 SEL, cooled down up to –10°C) working in single photon counting mode was  used. An electronic shutter is used to prevent the dimpling of the photomultiplier guaranteeing a 10µs time lag in acquisition. The data are acquired and stored  through a Multi-Channel Scaler (ORTEC) (dwell time≥ 100ns). In the improved version of ARETUSA set-up, the spectral measurements are performed using Broadband Bandpass Interference Filter (Edmund Optics) centered at  450nm, 550nm and 650 nm (50nm FWHM).