Introduction: Spectrophotometry is a well-established technique widely employed in chemistry, biology, medicine research, and industrial applications. It plays a crucial role in environmental testing, detecting pollutants in water and air. Many spectrometer models adopt a quartz cuvette. We investigated the replacement of the cuvette with a new sample holder coupled with SiliconPhotoMultiplier. Methods: This new holder, with the shape of an integrating sphere, offers several advantages since it is much less affected by sample stratification and turbidity. Furthermore, the high reflectivity of the cavity walls lets the light cross the sample many times, enhancing the sensitivity. We implemented a detailed Geant4 simulation to optimize this new sample holder and to provide its first characterization. A double-line spectrophotometer was assembled with two newly designed holders. The system foresees a pulsed light source …