# Presentation: 701177

##  		 THE FORWARD

_**PROTON **__**DETECTOR**__**  AT DZERO**_** **
**	****	****	**

-  Gilvan Alves
-   Lafex/CBPF

- 1) MOTIVATION
- 2) DETECTOR OPTIONS
- 3) FPD R&D
- 4) OUTLOOK
***          ******	***

**Lishep 98**
**Lafex/CBPF**
**Feb 17, 1998**

## Diffractive Kinematics

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

**  **

**  **

** **

**Detector**

## The Detector 

- 0.8mm

- The Detector

- UVX Planes

_**DETECTOR GOALS**_

-   Position resolution of 100μm
-  Efficiency close to 100%
-  Radiation Hardness
- High Rate capability
-  Low background rate
-  Small dead area close to the beam

## ACCEPTANCE

_**ACCEPTANCE**_

- Quadrupole ( *p* or     )

- Dipole (      only)

- Dipole acceptance better at low |t|, large 
- Cross section dominated by low |t|

- 0    0.02   0.04
-     1.4   1.4     1.3
-      2      35     95

- MX(GeV)

- 450
- 400
- 350
- 280
- 200

- GeV2

- GeV2

- 450
- 400
- 350
- 280
- 200

- MX(GeV)

- 

- 

**Geometric ******** Acceptance**

_**DETECTOR OPTIONS**_

## Slide 7

## Photon Detection Device

- Quantum Efficiency
- Light  Charge
-  VLPC ( 80%)
-  APD ( 70%)
-  Image Intensifier
-  	CCD ( 20%)
- 	Low rate
-   MAPMT ( 20%)
- VLPC the best option
- But... cryogenics$$$

_**DETECTOR 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

_**DETECTOR OPTIONS**_

- Scint Tile
- 800m thick

- Clear Fiber

- 4fibers  PMT

- 2 WLS fibers  PMT

_**DETECTOR OPTIONS**_

- Scint Fibers
- 800m

- Mirrored side

- Mirrored side

- 4fibers  PMT

- 4fibers  PMT

_**DETECTOR OPTIONS**_

- Pot

- Detector Active Area

- XY Plane

- UV Plane

- Pot

_**DETECTOR 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)

## Single PE

- Measurement
- H6568

- Scint. Tile
- +
- Clear Fiber

- <NPE>=3.0

- LED Calibration.

## Scint.  Fiber

- Output
- H6568

- Effect of cutting
-  Fiber at 45

- <NPE>=7.3

- <NPE>=6.8

## Similar to Uncut Straight Fibers

- Gain              Attenuation length
- Losses due to
-  Cutting Fiber at 45 (5%)
-  Fiber Splicing (5-10%)
-  Preferred Option
-  Accelerator Background
-  Cross Talk

- Scint.  Fiber
- + Clear Fiber
- Output
- H6568

- <NPE>=7.4

## Cross Talk Results

- H6568 1.3mm window thickness
- Improved by new 0.8mm window

- Using Scintillating Fibers w/o
- EMA => 25% increase

## Slide 18

## THE DETECTOR

- (u,u’,v,v’,x,x’)
- of 800 
- scintillator
- fibers (’) planes
- offset by 1/3
- fiber

_**THE DETECTOR**_

- 20 channels/plane(U,V)’
- 16 channels/plane(X,X’)
- 112 channels/detector
- 2016 total channels
- 80  teor. resolution

## THE DETECTOR

- 4 Fiber bundle
- fits well the
- pixel size of
- H6568 16 Ch.
- MAPMT
- 7 PMT’s/detector
- (most of the cost)

_**THE DETECTOR**_

**U**

**U’**

## SUMMARY

-  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**