Multiple radiator Optimisation of radiator parameters revisited Assumption

Multiple radiator: Optimisation of radiator parameters - revisited Assumption in the original calculation: refraction can be neglected for the optimisation studies. Refraction turns out to be important!

Radial photon impact point distribution d = (L-D 0) tan(Q 2) – (L-D 1) tan(Q 1) d= (L-D 0) (tan(Q 20) – tan(Q 10)) + D 1 tan(Q 12) Qi = Cherenkov angle, Qi 0 = photon angle in vacuum Q 12 = photon angle from tile 1 in tile 2

Minimized: error per track, same as before Distance to photon detector Number of photons Emission point error Pad size contribution Now assume srest=0. 006

Minimize track error vs. refractive index difference dn at fixed total thickness D 0=4 cm and relative radiator thickness k=0. 5 Minimum moves from dn=0. 012 0. 009

Minimize track error vs. Relative radiator thickness k at fixed total thickness D 0=4 cm and refractive index difference dn=0. 009 Minimum moves from k~0. 5 0. 44

Minimize track error vs. Relative radiator thickness k and refractive index difference dn at fixed total thickness D 0

Multiple radiators: comparison table

Do we see this in the data? YES Single photon sigma vs dn Data: my data points (similar to the ones shown by Kuratani-san three weeks ago). Curve: new calculation dn

new calculation old calculation

Data: Kuratani-san new calculation old calculation