# Presentation: 016065

## Pixel Efficiency in Overlap Region

- Hemma Mistry
- Kevin Lung, Ana Ovcharova, Boyan Tabakov
- Weiming Yao, Jim Siegrist

**URAP Project: Atlas Pixel Commissioning**
**Goal:**** Study pixel detector performances using pixel endcapA cosmic data and compare with Monte Carlo predictions in terms of pixel clustering, noise, resolution, and hit efficiencies as an undergraduate research project**

## Current Work

- Check cluster width vs. Incident Angle
- Check total cluster charge vs. Incident angle
- Compare Data and Monte Carlo
- Check hit efficiency in overlap region

## Cluster Width X vs. Incident Angle

-  Cluster width in local x vs. incident angle of track passing through disk
-  Data agrees well with Monte Carlo

***Cluster Width X vs. Incident Angle***

**X Projection**

**Y Profile**

**noise**

## Cluster Width Y vs. Incident Angle

-  Cluster width in local y vs. incident angle of track passing through disk
-  Data agrees well with Monte Carlo

***Cluster Width Y vs. Incident Angle***

**X Projection**

**Y Profile**

## Cluster Charge vs. Incident Angle

-  Total cluster charge (ToT) vs. incident angle of track passing though disk
-  Shift between Data and Monte Carlo

**X Projection**

**Y Profile**

**noise**

## Checking Efficiency

- Check hit efficiency in overlap regions
- Plot local x vs. local y of active overlap region
- Take hit on front of disk and extrapolate to back of disk to find expected hit
- Check if expected hit is within overlap region
- Check minimum distance between expected hit and real hit on module

## Local X vs. Local Y

**Local x**

**Local y**

***Local X vs. Local Y***
- Overlap Region - Even Modules

## Local X vs. Local Y

**Local x**

**Local y**

***Local X vs. Local Y***
- Overlap Region - Odd Modules

## Local X vs. Local Y

**Local x**

**Local y**

***Local X vs. Local Y***
- Overlap Region - Odd Modules

## Local X vs. Local Y For Each Disk

- Even Modules -Disk 0

- Even Modules -Disk 1

- Even Modules -Disk 2

- Odd Modules -Disk 0

- Odd Modules -Disk 1

- Odd Modules -Disk 2

## Extrapolate Hit on Front of Disk to Back of Disk

***Extrapolate Hit on Front of Disk to Back of Disk***

- Disk 0

- Disk 1

- Disk 2

- For each hit on the front of second disk, calculate expected coordinates on back of disk
- Check if within overlap region

## Find Expected Hit on Back of Disk

**X****A**

**X****B**

**Y****B**

**Y****A**

**X****A**, **Y****A** is the hit on the front of the disk
**X****B**, **Y****B** is the expected hit on the back 	of the disk

**X****B** = **X****A** + dz * tan(**θ**) * cos(**φ**)
**Y****B** = **Y****A** + dz * tan(**θ**) * sin(**φ**)

- dz

- z

- y

**θ**

**φ**

**(X****A****, Y****A****)**

**(X****B****, Y****B****)**

- y

- x

***Find Expected Hit on Back of Disk***

## Convert XB, YB to Local Coordinates

-  7.5 degrees between each module
-  angle = (3.75+7.5*module) * π/180
-  center of module:
-  X0 = 119.17 * cos(angle)
-  Y0 = 119.17 * sin(angle)

**Local x** = (XB – X0) * cos(angle + π/2) +(YB – Y0) * sin(angle + π/2)
**Local y** = (XB – X0) * sin(angle + π/2) -(YB – Y0) * cos(angle + π/2)

## Local X vs. Local Y

**Local x**

**Local y**

***Local X vs. Local Y***
- Overlap Region - Even Modules

**y > -26**
**x < 8**
**y < 8x – 50**

**y < (-16/5)x – 35.6**
**y > -26**
**x < 8**

## Efficiency in Overlap Region

**dr**

- dr = minimum distance between expected hit and actual pixel hit

***Efficiency in Overlap Region***
***Disk 1***

- dr = (Δx2 + Δy2)1⁄2

## Efficiency

- Total hits:		**864    ****	****	**

**784**

**864**

**=  .9074 +/- .01**

***Efficiency***

**90.74%**  dr < 1mm

**dr**

## Compare with Monte Carlo
Data agrees with Monte Carlo
Redefine fiducial region to see better efficiency

- Data

- Monte Carlo

**dr**

**dr**

***Efficiency for ***
***Second Disk***

- Compare with Monte Carlo
- Data agrees with Monte Carlo
- Redefine fiducial region to see better efficiency

**80**

**84**

**=  .9524 +/- .023**

**95.24 %** dr < 1mm

## Efficiency for Disk 0

**dr**

**dr**

**Data**

**Monte Carlo**

**565**

**793**

**=  .7125 +/- .016**

**71.25 %** dr < 1mm

**72**

**84**

**=  .8571 +/- .038**

**85.71 %** dr < 1mm

## Efficiency for Disk 2

***Efficiency for Disk 2***

**dr**

**dr**

**656**

**934**

**=  .7024 +/- .015**

**70.25 %** dr < 1mm

**Data**

**Monte Carlo**

**66**

**87**

**=  .7586 +/- .046**

**75.86 %** dr < 1mm

## To Do

- Tighten fiducial region to see if efficiency remains the same
- Check overlap efficiency as a function of the module in the disk
- Check overlap resolutions as a function of the size of pixel clusters to make sure both clusters contain same number of pixels
- Check global position of middle disk between other two disks