could ckov1 be come rich?
DESCRIPTION
Could CKOV1 be come RICH?. Gh. Grégoire. October 19, 2005. Contents. 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. Focusing geometries. - PowerPoint PPT PresentationTRANSCRIPT
Could CKOV1 become RICH?
1. Simulations2. Sensitive area of the detection plane3. Example of a workable solution4. Geometrical efficiency of the photon detecting plane
5. Conclusion
October 19, 2005
Gh. Grégoire
Contents
Focusing geometries
Non exhaustive ! Very preliminary ! Not optimized
Plane mirror
Spherical mirror
R=-1100 mm
Parabolic mirror
Rcurv=-1500 mm = -1
= 0
Spheroidal mirror
Rcurv= -600 mm along X
Rcurv=-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
12
00
mm
1200 mm
Simulations
• Momenta 190 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 radiator 20-mm thick
n=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)
• Particles Muons, pions and electrons (10 kevts each)
Diameter = 250 mm
3
Full beam
700 mm
700 mm
Muons only
700 mm
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 radiator135 < Radius of Č rings < 275 mm
4
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 eachSquare PM 26 x 26 mm
Just an example ! Not a proposal !
Gain 3.5 106 12 stages bialkali 300 < < 600 nm
5
Detection plane
Annular coverage270 mm < D < 550
mm
6
Detected photons
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100
Nr 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
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