1. Could CKOV1 become RICH? 1. Simulations 2. Sensitive area of the detection plane 3. Example of a workable solution 4. Geometrical efficiency of the photon detecting plane 5. Conclusion October 19, 2005 Gh. Grégoire Contents

2. Focusing geometries Non exhaustive ! Very preliminary ! Not optimized Plane mirror Spherical mirror R=-1100 mm Parabolic mirror R curv =-1500 mm  = -1  = 0 Spheroidal mirror R curv = -600 mm along X R curv =-1100 mm along Y More x-focusing obviously needed ! Goal: Č light produced at the focus to get a parallel beam after reflection and placing the detecting plane perpendicularly (for easy simulation/reconstruction)  400 mm 2 1200 mm

3. Simulations Momenta190 to 280 MeV/c ( in steps of 10 MeV/c ) Gaussian beams  x-y = 50 mm  x’-y’ = 25 mrad From S. Kahn’s presentation, Phone conf. March 31, 2005 Water radiator20-mm thickn=1.33 Index not too high to decrease size of rings Index not too low to get enough photoelectrons (Spheroidal) biconic mirror at 45° (curvatures not optimized) ParticlesMuons, pions and electrons (10 kevts each) Diameter = 250 mm 3

4. Full beam 700 mm Muons only 700 mm Pixel size 1 mm x 1 mm Losses < 5 10 -4 Biconic mirror ( not optimized ) 280 MeV/c190 MeV/c The detecting plane does not have to be sensitive over the full area Faint ring due to aberrations … For all muon momenta covered by MICE, For all impact positions and directions at the radiator 135 < Radius of Č rings < 275 mm 4

5. Detection element Hamamatsu assembly H8711 based on R7600 multianode PMT Imagine the detection plane is equiped with multianode PMTs like Hamamatsu H7600. 16 pixels 4 x 4 mm each Square PM 26 x 26 mm Just an example ! Not a proposal ! Gain 3.5 10 6 12 stages bialkali 300 < < 600 nm 5

6. Detection plane Annular coverage 270 mm < D < 550 mm 6

7. Detected photons Nr of photons reaching the detection plane = 89 (for muons of 280 MeV/c) assuming 100% light collection efficiency Average nr of anodes hits = 79 For Cherenkov rings, originating from muons hitting any position on the radiator Geometrical efficiency =89 % 7

8. Conclusion 1. One still gets enough photons to determine the radii of the rings 2. Next task: - a lot of optimization - detailed studies of aberrations with particles off axis 8 - to ease the simulation and analysis - but aberrations will not destroy the separation possibilities check that  -  separation at analysis level is still acceptable With a rough granularity of the photon detecting plane define a simple algorithm to identify pions from muons - the choice of a photon detection technique This is still a feasibility study confirming that CKOV1 could be made RICH To become a serious design work it needs