M. Bonesini 1

TOF design updates

M. Bonesini – INFN Milano

M. Bonesini 2

Scintillation counter: basic element (mounting assembly)

M. Bonesini 3

Scintillation counter construction

BC-404 or BC-420 scintillation slabs from Bicron (DTF finish)Home made plexiglass light guideHome made counter mounting (3 prototypes ready in Milano)Home made PMT holder

M. Bonesini 4

TOF 0 station optimization

Basic element: scintillator slab 24 cm x 4 cm x 1” with plexiglass light guide, read by R4998 mod PMTs2 planes X/Y : active area 24 x 24 cm2

Cross-calibration: impinging muons+laserMechanics design (CAD) in progress

M. Bonesini 5

CAD design for TOF0

•2 X/Y planes

•Problem: reduced capability of cross-calibration with incoming muons (as respect to staggered solution)

•But Advantage: more easy mechanics support structure and more uniform structure /less material on beamline

M. Bonesini 6

TOF1/2 stations optimization

Basic element: scintillator slab with plexiglass light-guides read by Hamamatsu R7761 fine-mesh PMTs (TOF2) or modified R4998 (TOF1)2 planes: X,Y oriented to allow multi-hits rejection capability (48 x 48 active area, 1” thickness)Each plane is made of 8 slabs to allow cross-calibration with impinging muons (width=6 cm), using X-Y viewCalibration: overlaps + laser systemMechanics design (CAD) in progress

M. Bonesini 7

CAD design for TOF2•2 X/Y planes

•Problem: reduced capability of cross-calibration with incoming muons (as respect to staggered solution)

•But Advantage: more easy mechanics support structure and more uniform structure/less material on beamline

ggg

M. Bonesini 8

X/Y planes front view

890 mm500 mm

M. Bonesini 9

X/Y planes top view

X plane

Y

Y plane

Y

M. Bonesini 10

Plexiglass lightguides

here we will hang to support structure the scintillation counters via a comb

M. Bonesini 11

G4MICE

G4MICE installed in Milano, to optimize TOF performances design (with help from Alessandra and Yangmur)

Hope to have results soon (multiplicity of hits, ...)

M. Bonesini 12

Conclusion

TOF0,TOF1/TOF2 design updated CAD design in progress tests to be done soon for:

1. PMTs timing behaviour in B-field (for R7761 and R4998 mod)

2. Rate effect for R4998 mod