One must remember that the hydrogen tanks will be operated in a turbulent mode, with potentially important optical distortions. Bien sur , since the absorbers are already there, and transparent, one would want to take advantage of the light they emit. If necessary a scintillating element such as neon could be added in small amounts in hydrogen to provide a good line. TY showed emission curves from a hydrogen lamp. Optical imaging of the scintillation in hydrogen would certainly offer excellent measurements of the beam size.
Cerenkov radiation provides particle separation and imaging of both angular and spatial information.
TY suggested that higher pressure or lower temperature could lower the threshold. A simulation of the CR light pattern produced by a realistic beam is necessary. AB proposed to do it. DK showed a break down analysis of the losses of muons from a study performed by AT . Various physical effects were turned on one by one.