The spectrophotometer is composed by two low-voltage halogen lamps placed at 45o to the normal to the painting surface, irradiating a small area, of nearly 5 cm2. The time stability is obtained by powering the lamps through a current-stabilized generator. A purpose-realised optical system gathers the back-diffused radiation from the investigated point on the painting and focuses it on the termination of a multimode optical fibre that carries the collected light to the sensitive surface of the detector.

This is a photomultiplier array characterized by 32 elements, where each element is filtered by an interferential filter (10nm FWHM) and the filter central wavelengths are 10/20 nm spaced thus covering the 380 800 nm spectral range. Adjustment and calibration procedures have been established.

The spectrophotometer is composed by two low-voltage halogen lamps placed at 45^o to the normal to the painting surface, irradiating a small area, of nearly 5 cm^2 . The time stability is obtained by powering the lamps through a current-stabilized generator. A purpose-realised optical system gathers the back-diffused radiation from the investigated point on the painting and focuses it on the termination of a multimode optical fibre that carries the collected light to the sensitive surface of the detector.

This is a photomultiplier array characterized by 32 elements, where each element is filtered by an interferential filter (10nm FWHM) and the filter central wavelengths are 10/20 nm spaced thus covering the 380¸800 nm spectral range. Adjustment and calibration procedures have been established.



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