Road to Physics

shrubflattenUrban and Civil

Nov 25, 2013 (3 years and 8 months ago)

72 views

1

Agostinho Gomes

LIP &
CFNUL

-

Lisbon

on behalf of

the
ATLAS

/
Tileca
l

group

The ATLAS
Tile

Calorimeter

Road to

Physics

2

Tile Calorimeter

3 cylinders, each one
composed of 64 modules

central Barrel

2 Extended Barrels

Guidelines for the central hadron calorimeter


Good hermeticity for
jets

and
E
T
miss



Jet energy resolution


Easy construction (
periodical structure
)

%
3
%
50


E
E

The ATLAS Tile Calorimeter

Barrel module

at LHC, p
-
p collisions, 14 TeV

3

Girder
-

PMTs and
electronics inside

sub
-
modules

r

z

f

Mechanical structure and principle


Scintillator

WLS fibre


Light produced in the
scintillators

is transported to
the PMTs
via WLS fibres

(double readout)

C
ell
s

defined by
grouping the WLS
fibres on PMT
s

Segmentation:

3 radial depths



= 0.1


0.1
(0.2

0.1 in last radial
compartment)

Basic period, 18mm

master plate (5mm)

spacer (4mm)

scintillator (3mm)

Periodical structure, iron and plastic scintillators

4

1 March 2004

Assembly of the Tile Calorimeter in the pit


10 Dec 2004

Barrel assembled

Going on and near future:

Installation of services

Commissioning of the electronics

Cosmic rays tests

Move Barrel to final position (z=0) in September

Assembly of Extended Barrel cylinders

5


calibration systems:


C
esium source
:


primary tool
for cell intercalibration


calibrates optics+PMT, special read
-
out, also used during
construction


laser:


monitors

PMTs + pulsed electronics. Linearity, dynamic
range


charge injection
system

(CIS):


calibration of front
-
end electronics. Useful diagnostic
pulses


calibration
using

test
beams (
~12%

of
the

modules)


in
-
situ calibration:



E/p
T

for single hadrons (e.g. coming from

-
decay)


Z/


+ jet: p
T

balance


W

jj


Calibration of the Tile Calorimeter


6

Testbeam


calibration phase (2001
-
2003)


Muons, pions and electrons using different beam geometries


9 Barrel Modules and 14 Extended Barrel Modules were
monitored/calibrated

Beam incidence
at 90
o


Incidence at
20
0

and
projective

EBs

Barrel

M0

7

~100 Npe/GeV

~80 Npe/GeV

Different
polystyrenes

Cs/muon ratios

Testbeam


calibration phase


muons, 90º

“slice” method

uniformity and photostatistics monitoring

muon signal
per cell:
RMS 2.5%

8

Pions are the
available hadrons
during test beam.

Typical response for
pions. Change in
resolution with


due
to transversal and
longitudinal leakage

Energy
resolution

180 GeV pions projective scan

e/h = 1.36

0.01 over 0.15<|

|<0.55


calorimeter is not compensated

Testbeam


calibration phase


9

Combined test beam setup with all
the ATLAS sub
-
detectors

Combined Testbeam


10

1/

E
beam

σ
/
E
rec
[GeV]

Pions, resolution for Barrel, Tilecal “standalone” in CTB 2004

Combined Testbeam (CTB)


mip in cryostat scintillator or gap counter


mip in each layer of LAr calorimeter


Selection of
p

interacting only in Tilecal:

Trying to understand only Tilecal

Compare with previous testbeams

11

2004 Combined TB

1997 and 1998 standalone TB



a [%] GeV
1/2

b [%]

a [%] GeV
1/2

b [%]

0.25

54


1

5.9


0.1

59.10

5.40

0.35

57


1

5.6


0.1

56.30

6.88

0.45

54


1

5.4


0.1

56.50

5.35

0.55

50


2

5.3


0.1

55.20

5.10

1.1

43


5

5.0


0.4

46.7

5.34

1.2

52


6

5.4


0.5

43.7

4.8


Resolution for Tilecal “standalone” :

σ
/E = a/

E



b


In the extended barrel of 1997 the cell geometry was not the same

Combined Testbeam

12

_

G4



Data

LAr

_

G4



Data

TileCal

_

G4



Data

Total

Combined Testbeam


data and Geant4

Energy in LAr, Tilecal and total, pions 350 GeV

Still to be understood

13

Combined Testbeam


data and Geant4

Suspected problem in
Tilecal HV for this run

Lateral shower profile needs to be improved

E
(data)
/E
(Geant4)

Overall agreement within ~2% at

=0.35

(excl. 320 GeV)



Lateral shower profile, pions 180 GeV,

=0.35

14

The reconstructed energy E
rec

is


i
i
MC
i
i
c
E
E
E
w
E
)
,
(
Re


where i is the sample

i
MC
i
MC
i
MC
i
i
E
E
b
E
a
E
E
w
)
(
)
(
)
,
(


A fast look at jets
-

MC

Full DC1 dijet samples have been used

Jets reconstructed using cone algorithm

Look only at easiest region, |
η
| < 0.7


Tilecal Barrel,
far from cracks

Calorimeters will be calibrated at the EM scale

Jets need to be recalibrated (first step: detector
effects, e/
h ratio)

Later step will be correction of out of cone energy, ISR, FSR
using in situ Z/


+jet balance or W


jj

15

A fast look at jets
-

MC

Linearity is recovered

E
T

resolution

16

Setup for cosmics in the pit (June 2005)



8 superdrawers (modules LBA/C 13,14, 45, 46)



8 sets of temporary cables (TTC/GLINK, CANbus, trigger, laser/LED)
to electronics racks in room USA15



8 temporary LVPS + capacitors to filter noise



2 temporary cooling units + hoses to 8 modules

17

MobiDAQ

Trigger and DAQ

Event Scaler

CANbus

TTC fibres

Coincidence boards

(trigger cables in back)

Expert

Cosmics
-

18

1. Back to back towers (barrel) 2. Single tower (ext. barrel or barrel)


Cosmics
-

2 Trigger Modes

19

Event with
back
-
to
-

back

trigger





June 2005

Cosmics

20

Cosmics
-

Data
-
MC comparison

21

Conclusions



The Barrel cylinder is assembled in the pit and the 2 Extended
Barrel will follow soon



Commissioning of Barrel is underway



Combined test beam with all ATLAS sub
-
detectors done. Tilecal
energy resolution compatible with previous standalone testbeams.
Monte Carlo simulation using G4 still needs some tuning.


Calibration strategies for jets are underway


Commissioning with cosmic muons: preliminary test made in the pit
with Tilecal Barrel was a success
(we have not yet the LHC but we
got already physics data from the sky...)