The so-called tin plague is often related to the progressive decay of metal organ pipes. Tin plague is an allotropic transformation of tin, spontaneously occurring at temperatures of 13.2 °C: it is strongly accelerated by lower temperatures, highly humid atmosphere or high concentration of halide and delayed by the addition of Pb, Sb or other metals to the cast. Due to the paramount relevance of pipe organs in European musical tradition, non-destructive techniques are mandatory for diagnosis studies. We already performed neutron diffraction (ND) on several samples coming from the restoration of organs in Italy (XVII-XX century). In order to infer information on the elusive tin alpha phase, we plan to perform a comparison study on reference samples of alpha and beta tin phases, for the benefit of the study of real organ pipes samples.