Study of scintillation in natural and synthetic quartz and methacrylate
  Samples from different materials typically used as optical windows or light guides in scintillation detectors were studied in a very low background environment, at the Canfranc Underground Laboratory, searching for scintillation. A positive result can be confirmed for natural quartz: two distinct scintillation components have been identified, not being excited by an external gamma source. Although similar effect has not been observed neither for synthetic quartz nor for methacrylate, a fast light emission excited by intense gamma flux is evidenced for all the samples in our measurements. These results could affect the use of these materials in low energy applications of scintillation detectors requiring low radioactive background conditions, as they entail a source of background. 
J. Amare, S. Borjabad, S. Cebrian, C. Cuesta, D. Fortuno, E. Garcia,   C. Ginestra, H. Gomez, D.C. Herrera, M. Martinez, M.A...
physics.optics hep-ex physics.ins-det