# Presentation: 049612

## The ATLAS Liquid Argon Calorimeter Commissioning

- The ATLAS liquid argon (LArg) calorimeter system consists of an electromagnetic (EM) barrel calorimeter and two end caps with EM, hadronic and forward calorimeters. The ATLAS EM barrel (EMB) and the two end cap (EMEC, HEC and FCal) calorimeters were installed in the ATLAS cavern and the front-end electronics are being connected and tested.

** ****Liquid Argon Calorimeter              **

**The ATLAS Liquid Argon Calorimeter Commissioning**
***Hong Ma, Fabien Tarrade***
***Brookhaven National Laboratory, New York*****  **

**  ****Signal Reconstruction              **

** ****Electromagnetic Barrel**** (EMB)**
-   accordion geometry **Pb-LArg**
-   **101,760** readout channels
** ****Electromagnetic Endcap**** (EMEC)**
-   accordion geometry **Pb-LArg**
-   **62,208** readout channels
** ****Presampler**
-   active layer **LArg**
-   **7,808** (barrel), **1536** (endcaps) channels
** ****Hadronic Endcap**** (HEC)**
**  **plate geometry** ****Cu-LArg**  **  **
-   **5,632** readout channels
** ****Forward Calorimeter**** (FCal)**
-   matrix **Cu**/**Tungsten-LArg**
-   **3,524** readout channels

**all **sub-detectors with** similar LArg signal pulse shapes**

**182,468 cells for Liquid Argon Calorimeter**
**dead readout channels much below that 1%**

**construction** and **installation** in the pit:  **finished**
**all **detectors filled with** LArg : 89 K**;** **HV : **partial **
**electronics**’ installation/commissioning : **on going**

** ****Electromagnetic Barrel Readout chain**

- energy **E** :
- - pedestal **P**
- - Optimal Filtering Coefficient **a****i**
- - ADC→MeV **F**

**pedestal, noise auto-correlation function, and signal shape **
****** ****from commissioning**

**pedestal RMS (ADC)**

- + without 2nd filter
- + with 2nd filter

**basic** detector **functionality**
- - exercise **Front-End** electronics
- - look for **dead/bad **channels
- -** cabling**, channel **mapping**
- -** **measure **noise**
- - **readout**/**trigger** chain
- - full **LVL1**/**TDAQ**/**online**/**offline** chain
- - **interfaces** between : **DAQ**, **DCS**, **DB**
**calibration** run
- - check **pulse shapes**
- -** initial** calibration constants
- - measure **cross-talk**
**cosmics commissioning **run
- -** **check **pulse shapes** with **cosmic muons**
- - signal **reconstruction**
- - signal/noise **separation**
- - check/adjust detector** timing** at **1 ns **level
- - check cell response **uniformity** at **1%** level
- - calorimeter position with respect to other detectors (<1 mm)

**  ****Commissioning Goals and Results           **

**interferences**/**interplay** :                                                     -between **sub-detectors**                                                         -and with **trigger**
**calibration data** provide :                                                     -a **good understanding** of the **LArg waves**                                 -first **calibration coefficients**
**cosmics data** provide a **first **understanding :                          - **timing**                                                                                - **uniformity**                                                                         - **energy** reconstruction of the ATLAS **LArg calorimeters**

**  ****Conclusions ****& Outlook ****              **

** ****Conclusion **

** ****Outlook **

** ****Cosmics Commissioning Results **

**need 70 000 projective muons ******** 3 months data-taking**

** ****Commissioning Goals **

- dead cell

- 17 MHz noise

- pulsed middle cell
- neighbor strips
- long distance strips

**t (ns)**

**amplitude (ADC)**

**channel number**

- cross-talk, EMB

**simulation of 10 ms **
**of cosmics muon**

** ****Trigger and Data Acquisition **

** ****Muon ID and LArg clustering **

** ****LArg Timing **

**to check 1% non uniformity at cell level : average 16 times more statistics**

- from **5 samples **to **29 samples : noise **reduced by a** factor of 1.7**
**uniformity** : error bar per point is **~2 %** on average (top **3-4%,** bottom **1-2%**)

**noise (MeV)**

**number of sample**

- 50

- 50

**noise reduction**

- f(x)=p0 + p2*exp(p1*x)

**normalized **

**normalized to 1**

- ~9200 muons

- TOP

- BOTTOM

****

**uniformity**

**8 dedicated** trigger boards using **TileCal** :**  ****         - 4 **barrel
- - **4** **extended **barrel
- data taken **~weekly**

- -** ****barrel** : use middle layer: **muon S/N ~ 7**
- - **endcap**: muon **S/N ~2-5** (**EMEC **& **HEC** but not **FCal**)
- check with** TileCal **algorithm to find a **muon track**

- use **TileCal** to get **timing **of the muon at y=0 plane  correct for **TOF** to EM (**middle layer**)
- -** **check **cable lengths**, **descriptions**, **offsets**
- -** tune** timing
- reconstruct **LArg energy**

**   ****event display  **

- continue** commissioning **with** cosmic muons**                                                                                             with **commissioning** of the **LCH **machine** **use :               -**beam halo**                                                      -**beam-gas **collisions

****  **be ready for the first collision in July 2008**

**  ****Cosmic Muon Results              **

- timing studies

**TileCal time corrected for TOF (ns)**

**EM time from OFC (ns)**

**LArg energy **

**LArg energy**

**HEC0**

**EMEC2**

- (with all conditions data)

- (with all conditions data)

- energy reconstruction

- energy reconstruction

**  ****Cosmic Ray Running              **