RawHits in Pixel/SCT

Kohei YoritaThe University of Chicago

FTK Meeting on Feb. 21st 2007

2

Pixel Detector Drawing<- X-Y view of PixelEach line corresponds to a module.Layer 1 : 22 ModulesLayer 2 : 38 ModulesLayer 3 : 52 Modules

In each module, #Row increasesas Black->Red->Green->Blue“counterclockwise” in phi.

Z-X view of Pixel ->13 Modules in Z : (EtaModule)In each module, #Column increasesas Black->Red->Green->Blue->YellowLess hits in high eta due to MC trackgeneration (|eta|<1.0)Numbering looks consistent in all module.

One module

x

y

x

z

3

More on Pixel module (just to be sure)

Row# Row#

Row# Column#

yx

phi z

In Each module, index is Row (phi): 0-327 (328)Column (z) : 0-143 (144)

Both Row & Column numbers aremonotonically increasing !8 Row points (row#=160-167)look like dead channel (no hits.). Why ?

Same plot but all modules in layer1

4

# of Entry : Strange spikes ?

> Left (row): 0 entry (hole) in middle 8 points (#row: 160-167). instead, 4x2 spikes (~double entry) before/after the gap.

> Right (column) : 9 spikes (~ higher by 40%)

-> These should be due to the gaps between FE chips that have to be fully covered in readout.

#Row #Column

4 x 4

5

“Ganged” Pixel (Row) & “Longed” Pixel (Column)

Row (phi) : Two-fold ambiguity remains.Column(z) : Continuous but 9 points givehigher occupancy -> less resolution. column

row

8chips

In the region between different FE chips,Pixels are either - Longer(600um) for column (z) direction -> Total 9 edges that have x1.5 longer pixel.- Ganged for row (phi) direction. (8cells) -> 4points x each side (before/after gap).

6

SCT Detector Drawing<- X-Y view of SCTEach line corresponds to a module.Layer 1 : 32 ModulesLayer 2 : 40 ModulesLayer 3 : 48 ModulesLayer 4 : 56 ModulesIn each module, #strip increasesas Black->Red->Green->Blue->Yellow->..“counterclockwise” in phi.

768strip

In r-phi plane,Each strip has same Z=Z(center)

In stereo planeEach strip has different Z

~2.4mm (=tan(0.04)x60mm)

z

Black : r-phiRed : Stereo

z (mm)

7

A Module in SCT (Layer1)Side 1 (r-phi) Side 0 (z)

-> Strip Number (0-767) increases monotonically.-> Z-coordinate is different between side 1 and side 0 due to 40 mrad rotation. -> Even though two submodules are glued in one module, 6x6->6x12(z), those readouts are treated as if there is no physical gap. (the same readout)

Strip# Strip#

Strip# Strip#

yx

phi z

Strip# Strip#

Strip# Strip#

yx

phi z

768strip

1 readout

8

But Be Careful !!!Side0/Side1 definition is different in

different layers

Radius (mm)

Orientation

Side=0 Side=1

Layer1 300 Phi/u Stereo r-phiLayer2 373 Phi/v r-phi Stereo

Layer3 447 Phi/u Stereo r-phiLayer4 520 Phi/v r-phi Stereo

u(v) corresponds to +40mrad(-40mrad) stereo angle

-> Have to be careful in coding (choice of side e.t.c.).

9

Comparisons between SP & RawHitsUsing ~100K single muon training data sample.-> In principle event by event comparison is possible.

Pixel 0hit 1hit 2hits >3hits

SP ~1% ~87% ~10% ~2%

Raw ~1% ~45% ~40% ~14%

SCT 0hit 1hit 2hits >3hits

SP ~2% ~93% ~4% ~1%

Raw ~1% ~1% ~88% ~10%

10

Picking up events with ==2hits/layer in Pixel

SP Raw

* Not in use

In rawhits, two hits are always in the same module.-> In a module, most of them are adjacent in phi(60%) and eta(40%).

Module Difference

Module Difference

Row/columnDifference

Row/columnDifference

11

Picking up events with ==2hits/layer in SCT

SP : ~70% of the events (with two hits) are in different modules. RawHits: two hits corresponds to r-phi and stereo side in one module.

SP Raw

* Not in use

Module Difference

Module Difference

Side/StripDifference

Side/StripDifference

12

What’s happening in cross points between side0 and

side1 ?

….. …..

….. …..

i

i

i-1i-2 i+2i+1i-N+1i-N i+Ni+N-1

12cm

N = sin(40mrad)x768 = 30.7-> So expect ~60 cross points between r-phi and stereo plane.

13

Finding “Sector”> Running pattgen with “sector mode”.

> Track finding efficiency

SP RawHits

Pixel(111) 62% 11%

Pixel(111)+SCT(0111)

47% 0%

Pixel(111)+SCT(0111)

Only r-phi

- 7.6%

Number of track found by pattgen :SP : 30284x1.814=54945Raw : 6146x1.416=87038703/54945=16%

-> Next step is how to choose it.

104 sector survive

Only 1 sector survive

14

What’s done so far & To do> Numbering & data quality check : almost done -> basically monotonous function but we need to be careful for

handling of gaps (pixel) and side definition (SCT) > Modified codes for rawhit input : done Just to include flag “S” (rawhits). Now rawhits are readable for pattgen/corrgen/ftksim> Removed stereo hit in SCT (for now) : done

> Should make criteria to choose layers (1D or 2D).> First Try : Random pick-up routine for each pixel layer if hits are

nearby (easy-check), then averaging…> Generate constants> And more to follow (I need to know what can be done and can n

ot be done ... Still learning.