DD THE FORWARDTHE FORWARDPROTON PROTON DETECTORDETECTOR AT DZERO AT DZERO

Gilvan Alves Lafex/CBPF

1) MOTIVATION

2) DETECTOR OPTIONS

3) FPD R&D

4) OUTLOOK Lishep 98

Lafex/CBPFFeb 17, 1998

ion Collaborat OD

DD

pBeam pF

P2)( FBeam PPt

P

Pxp

1

sM x

Diffractive Kinematics

Rapidity Gap Approach Need to Tag and Measure p( p )

p p

Detector

DD

Y - Pot

X - Pot

Beam Axis

8BeamEnvelope

14.4mm

20mm6.

8mm

0.8mm

The Detector

UVX Planes

DD

DETECTOR GOALSDETECTOR GOALS

• Position resolution of 100µm

• Efficiency close to 100%

• Radiation Hardness

•High Rate capability

• Low background rate

• Small dead area close to the beam

DDACCEPTANCEQuadrupole ( p or )p

Dipole ( only)p

Dipole acceptance better at low |t|, large Cross section dominated by low |t| ||6/ tedtd

0 0.02 0.04 1.4 1.4 1.3 2 35 95

(%)AQuadrupole Dipole

MX (G

eV)

450

400

350

280

200

GeV2

GeV2

450

400

350

280

200

MX (G

eV)

Geo

met

ric

A

ccep

tan

ce

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DETECTOR OPTIONSDETECTOR OPTIONS

Detector Pro Con

Silicon SuperiorResolution

Dead AreaTrigger

MSGC GoodResolution

Dead Area

Fiber AdequateResolution

Light Out.

DD

photonageneratetoenergyeffectivetheisE

efficiencyquantumfiberscitheisQ

efficiencyconversionlightfiberscitheisC

corefibertheofvolumefractionaltheisV

fibertheinparticletheoflengthpatheffectivetheisx

where

E

QCVx

dx

dE

eff

s

s

eff

ssY

nAttenuatioFiberA

EfficiencyTrappingF

YieldInitialY

AFYY

YYieldLight

.

.

)(0

0

0

04.0

1

)(

DD

Photon Detection DeviceQuantum Efficiency Light Charge

• VLPC ( 80%)• APD ( 70%)• Image Intensifier CCD ( 20%)

Low rate • MAPMT ( 20%)

VLPC the best optionBut... cryogenics$$$

DD

DETECTOR OPTIONSDETECTOR OPTIONS

Fiber Options Investigated

Scint. Tile to Clear Fiber

Scint. Tile to WLS Fiber

Scint. Fiber Straight

Scint. Fiber to Clear Fiber

Round vs. Square Fibers

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DETECTOR OPTIONSDETECTOR OPTIONS

Scint Tile800m thick

Clear Fiber

Scint Tile800m thick

WLS fiber

4fibers PMT

2 WLS fibers PMT

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DETECTOR OPTIONSDETECTOR OPTIONS

Scint Fibers800m

Scint Fibers800m

Clear fiber

Mirrored side

Mirrored side 4fibers PMT

4fibers PMT

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DETECTOR OPTIONSDETECTOR OPTIONS

Pot

Detector Active Area

XY Plane

UV Plane

Pot

DD

DETECTOR OPTIONSDETECTOR OPTIONS

Square Fibers Increase

light Yields by 20%

Scint. Tile to Clear Fiber or

WLS discarded for low yield

Reduce Pot Size Using tilted

planes (U,V)

Fiber bend does not affect

performance(limited to = 5cm)

DDSingle PE

MeasurementH6568

Scint. Tile+

Clear Fiber

<NPE>=3.0

LED Calibration.

DDScint. Fiber

OutputH6568

Effect of cutting Fiber at 45

<NPE>=7.3

<NPE>=6.8

DD

Similar to Uncut Straight FibersGain Attenuation length Losses due to• Cutting Fiber at 45 (5%)• Fiber Splicing (5-10%)

# Preferred Option • Accelerator Background• Cross Talk

Scint. Fiber+ Clear Fiber

OutputH6568

<NPE>=7.4

DDCross Talk ResultsH6568 1.3mm window thickness

Improved by new 0.8mm window

0.4 0.6 0.3 *

1.2 100 2.2 *

0.4 1.0 0.3 *

* 0.08 * *

Using Scintillating Fibers w/oEMA => 25% increase

DDEfficiency MeasurementUse 106

44Ru 3.5 MeV e- Source

Source

Collimator

D

T1T2

D - Detector Cell T1&T2 - Trigger Scintillators

= 90-95%(not corrected for background)

DD

Six planes(u,u’,v,v’,x,x’)of 800 scintillatorfibers (’) planesoffset by 1/3fiber

THE DETECTOR

20 channels/plane(U,V)’16 channels/plane(X,X’)112 channels/detector2016 total channels80 teor. resolution

DD

4 Fiber bundlefits well thepixel size ofH6568 16 Ch.MAPMT

7 PMT’s/detector(most of the cost)

THE DETECTOR

UU’

DDSUMMARY

• Fiber Detector represents the best option

• Prototype being built for beam/cosmic tests

• FPD will be a completely integrated sub-detector of the detector which will help maximize Run II physics potential

• Hard diffraction needs large data samples and precise measurements

OD OD