Forward Preshower Detector Overview




Postscript Slide
Postscript Slide


Detector Parameters

Item Description
Number of detectors 2 (one on each end cryostat: North & South)
Inner (outer) radius (mm) 200 (1682.75)
Detector geometrical shape (contour) 100.091 inch (spherical, conforming) radius of EC head
Module opening angle (in f) 22.096 degrees (2D, flat projection angle subtending with beam axis)
Module-to-Module overlap region 0.5 inch
Detectors radially above (below) FPS ICD (Level 0 Luminosity Monitor)
Active material nested scintillator strips of triangular cross-section
(Extruded: 5.4 mm base, approx. equilateral)
Readout principle WLS fibers, clear waveguide, VLPCs, SVXIIe (Diagram)
FPS detector-side optical connector 16-channel, square 4x4 fiber matrix (Material: Black ABS)
Dimensions: 6.4mm x 22.0mm x 7.0mm (for 0.835 mm WLS fiber)
(Front Polished View, WLS Side)
f-segmentation 32 x 2 trapezoidal f-wedges
z-segmentation 4 (two u,v) layers per side
Label Scheme: Layers 1,2 (Shower) & Layers 3,4 (MIP)
Strip geometry 22.5 degree stereo (u,v)
FPS Readout Sector Layers 1&3 and Layers 2&4 (according to f-segmentation)
Absorber: (2D View, 3D View) 2Xo Lead (forty-eight 7.5 degree f-wedges: Pb+SS+Pb)
h-coverage of absorber 1.65 < |h| < 2.5
At soleniod f(=27.054 deg.): wedges-cut: 1.8 < |h| < 2.5
Total channels downstream (Layers 1,2) North: 4316, South: 4316
Total channels upstream (Layers 3,4) North: 3168, South: 3168
Calibration/Monitoring System 968 blue surface-mount LEDs (N+S) on 18-pin pc-boards
LED/fiber pc-boards: 60(North) + 60(South)
LED calib. hollow-cylinders: 484(North) + 484(South)
Clear waveguides 2(N)+2(S) notches: 16 256-channel clear bundles per notch
Length: TBD (initial estimate: 11 to 14 m)
Approximate weight 222 kg. (495 lbs.) per side


FPS Module Parameters

Module Type
No. of Modules
(per detector)
No. of Modules
(North+South)
No. WLS Connectors
(16-chan., per module)
No. Channels
(per module:
u+v stereo)
|h|-Coverage
1. Large Module (Layers 1,2)
14
28
18
288
1.50 < |h| < 2.5
2. Small Module (Layers 3,4)
14
28
14
206
1.65 < |h| < 2.5
3. Special Module (at solenoid services)
4
8
9
142
1.80 < |h| < 2.5
Total FPS:
32
64
968
14,968
1.50 < |h| < 2.5

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Information last updated: Jan. 18, 2000, by Abid Patwa