# Presentation: 038014

## ATLAS commissioning   with cosmic muons and initial beam 

**Pavel Nevski (BNL/CERN) **
**  ****for Cosmic&Halo group**

- 5 June 2003

## Overview

**In 2006 a significant part of the ATLAS detector will be installed and commissioned**
**Scheduled ~ 40 days of cosmic running end 2006**
**Could also imagine cosmic running with only calorimeters earlier, and further running in January—March 2007 (machine cool down)**
**Expect 2 months of single beam running in 2007. Together with cosmics, this will chase the first particles through Atlas**
** *****How to make  this time USEFUL?***

- 5 June 2003

##  Cosmic & Halo group: 
        	M.Boonekamp, F.Gianotti, R.McPherson,  	P.Nevski, J.Pinfold, R.Soluk
 Mandate:
      	Make estimates and initiate discussions
Initial study:
Cosmic rates entering ATLAS cavern
Rates in different detector elements
Calorimeter energy deposition
Trigger issue
Offline Reconstruction

**        ****	****M.Boonekamp, F.Gianotti, R.McPherson,  ****	****P.Nevski, J.Pinfold, R.Soluk**
** ****Mandate:**
**      ****	****Make estimates and initiate discussions**
**Initial study:**
**Cosmic rates entering ATLAS cavern**
**Rates in different detector elements**
**Calorimeter energy deposition**
**Trigger issue**
**Offline Reconstruction**

**Commissioning study**

- 5 June 2003

## ATLAS Cavern

**SX1**

**PX14**

**PX16**

**PX15**

**UX15**

**USA15**

**Shafts (PX14 and PX16) ******** Large windows**
**Critical to include in simulation **
**Geometry**
**Surface buildings**
**PX14, PX16**
**Shielding**
**Concrete**
** ...**

- 5 June 2003

## Cosmic muons in ATLAS

**Cosmic muons in ATLAS**

_**Rock ~ Silicon**_
**600m x 600m x 200m deep**
**(2.33 g/cm****3****)**

_**Air**_

_**Concrete**_
**Density = 2.5 g/cm****3**
**Surface building**
**PX14/16 shielding**

**PX14 **
**(18 m Inner Dia.)**

**PX16 **
**(12.6 m Inner Dia.)**

**Full ATLAS Geant 3 Simulation (atlsim)**
**  ****- Release 6.0.3**
**  ****- Initial detector**
**  ****- Full B fields**

- 5 June 2003

## Cosmic  Flux

**Two generators used so far**
**PDG approximation formula**
**Single muon flux (Energy, cos ********)**
**Neglects muon decay-in-flight**
**Fit to measured fluxes**** **
**Code from Alois Putzer (ALEPH simulation)**
**Agrees at few % level with measured fluxes**
**Allkofer et al, Phys. Lett. 36B (1971), 425; A. Dar, Phys. Rev. Lett. 51 (1983), 227**
**Agreement ******** 20% level between 2 generators**
**Third generator also under study (Soluk)**
**“****CORSIKA” full cosmic ray shower program**
**Useful for cosmic ray physics studies with ATLAS**
**Includes “multi-muon” events, not present in other generators**

- 5 June 2003

## Samples studied

**Single ******** flux with cuts:**
**SURFACE :**
**0.35 < ****cos ******** < 1 **
** ****(above 70****o**** hit earth’s curvature)**
**10 GeV < E******** < 5000 GeV**
**-300 m < X****0**** < +300m**
**-300 m < Z****0**** < +300m**
** ****(allow ******** at 70****o ****to enter ATLAS cavern)**
**ATLAS Y=0: use speed-up cuts (track extrapolation)**
**-30 m < X(Y=0) < +30 m**
**-30 m < Z(Y=0) < +30 m**

|  | PDG | ALEPH |
| --- | --- | --- |
| Surface rate | 6.3 x 10-3  /cm2/s | 3.0 x 10-3  /cm2/s
 |
| Cavern rate | 5.9 kHz | 4.9 kHz |
| Gen.  surface | 9 x 109 | 9 x 109 |
| Gen.  cavern | 2.4 x 106 | 4.1 x 106 |
| time | 398 sec | 828 sec |

- 5 June 2003

## Cosmics  in 0.01 sec 

**Cosmics ******** in 0.01 sec **

- 5 June 2003

## Muon Momentum Distributions ... 

**Muon Momentum Distributions ... **

**“****Digit”:**** **
**Any G3 digit (mostly MDT)**** **

- 5 June 2003

## Trough-going the whole ATLAS... 

**Trough-going the whole ATLAS... **

**RPC digit, Y>0**
**RPC digit, Y<0**
**ID Digits **
**Can(?) adjust LVL1 RPC trigger for these**

- 5 June 2003

## Looking Like Real Collisions ... 

**Looking Like Real Collisions ... **

**RPC digit, Y>0**
**RPC digit, Y<0**
**Pixel Digits **
**LVL1 RPC trigger should work (with timing adjustments)**

- 5 June 2003

## One track reconstruted in muon chambers
Two tracks reconstructed in Inner Detector
Will happen every 10 seconds (!)

**Two tracks reconstructed in Inner Detector**
**Will happen every 10 seconds (!)**

**A “typical” Event**

- 5 June 2003

## Porig=-5.56

Pmu=+7.40

Pid1= -2.11
Pid2=+2.15

**Pmu=+7.40**
**Pid1= -2.11**
**Pid2=+2.15**

**Same Event in Inner Detector**

- 5 June 2003

## EM Cal Transverse Energies

**EM endcaps and barrel**
**ECALREC for reconstruction and clustering**
**EM Scale**

- 5 June 2003

## Tile Energy

**Tile calorimeter**
**Used DIGI(4) for energy**
**EM Scale**

- 5 June 2003

## Rates Summary (syst error =  10%)

| System | Condition | Rate | (Hz) |
| --- | --- | --- | --- |
|  |  | Esurface>10GeV (PDG Gen) | Esurface>10GeV (ALEPH Gen) |
| ATLAS UX15 | -- | 5900 | 4900 |
| Any G3 Digit | -- | 2800 | 2300 |
| Through | RPCY>0 x RPCY<0 x IDDIGI | 28 | 24 |
| Going | RPCY>0 x RPCY<0 x PIXDIGI | 0.6 | 0.4 |
| Passed | |ZDIGI| < 300,  |RDIGI| < 60 cm | 12.2 | 10.2 |
|        origin | |ZDIGI| < 100,  |RDIGI| < 30 cm | 2.3 | 1.9 |
|  | |ZDIGI| < 60,    |RDIGI| < 20cm | 0.6 | 0.5 |
|  | ETCELL        >  5 GeV | 0.1 | 0.1 |
| EM Cal | ETCLUSTER >  5 GeV | 0.2 | 0.2 |
|  | ETTOTAL      >  5 GeV | 0.4 | 0.4 |
| Tile Cal | ETOTAL        > 20 GeV | 1.4 | 1.2 |
| HEC | ETOTAL       > 20 GeV | 0.1 | 0.1 |
| FCAL | ETOTAL       > 20 GeV | 0.02 | 0.02 |

- 5 June 2003

## NOT a typical eventbut may be more useful to calibrate detector (?)

- 5 June 2003

## Machine Sources: Beam Halo, Beam Gas

- Beam-Gas

- Beam-Halo

**Standalone simulations using MARS, Protvino group, V.Talanov et al**
**Scoring plane at the cavern entrance, before ATLAS shielding**
**Vacuum estimates : ~3.10****-8**** Torr (~10****15**** mol/m****3****)**
**Recent Machine Optics version 6.4**
**Nominal machine current : 530 mA**

- Scoring plane

**Machine Sources: ****Beam Halo, Beam Gas**

- 5 June 2003

## Beam HaloRates at cavern entrance

| Particle | Rate |
| --- | --- |
|    All | 1750 kHz |
|    h± | 1515 kHz |
|    n | 130 kHz  |
|  | 105 kHz |
|    10 GeV | 16 kHz  |
| eV | 1 kHz  |
| TeV | 10 Hz  |

- Table 1

- 5 June 2003

## Beam HaloRates at cavern entrance

- Not simulated yet, will be mostly absorbed by the shielding

- 5 June 2003

## Beam HaloRates at cavern entrance

|    h±, large radius : |
| --- |
| 38 kHz |

- 5 June 2003

## Beam Halo through ATLAS Detector

**Single beam run : machine current ~200 times lower**
**	****Less protons, less bunches.**
**	****	******** ********10 GeV : 100 Hz (tot. 1,7.10****8****)**
**	****     ****	******** ****h****±****, large R :**** 0.2 kHz     (tot. 3,5.10****8****)**
**Hadrons discarded from this study **
**New shielding design not yet implemented**
**( punch-through uncertain but should be small )**
**Halo muons simulated in Atlsim**

- 5 June 2003

## Beam HaloTypical(!) Event

**Beam Halo****Typical(!) Event**

- 5 June 2003

## Beam HaloMuon Rates in Atlas - 1

| Detector | Rate (F.Off) | Total (F.Off) | Rate (F.On) | Total (F.On) |
| --- | --- | --- | --- | --- |
| MDT barrel | 14,7 Hz | 2,5.107 | 72,4 Hz | 1,3.108 |
| MDT endcap | 145,0 Hz | 2,5.108 | 136,3 Hz | 2,4.108 |
| Pixel | 1,8 Hz | 3,0.106 | 1,9 Hz | 3,2.106 |
| SCT | 17,2 Hz | 3,0.107 | 18,9 Hz | 3,2.107 |
| TRT | 28,2 Hz | 4,9.107 | 30,5 Hz | 5,3.107 |

**Naïve (?) requirements for “useful tracks”**
**Fields Off : 2 segments in MDTs, 3 wheels/disks in ID (endcap)**
**Fields On : 3 segments in MDTs, 4 wheels/disks in ID (endcap)**

- 5 June 2003

## Beam HaloMuon Rates in Atlas - 2

**Calorimeter energy deposition : **
**	****E****TOT****, more than 5 GeV in EMC, 20 GeV in Tile and HEC, 50 GeV in FCal (for had calorimeters, E is just MIP****×****EM scale...)**

| Detector | Rate (F.Off) | Total (F.Off) | Rate (F.On) | Total (F.On) |
| --- | --- | --- | --- | --- |
| EM | 2,1 Hz | 3,6.106 | 1,2 Hz | 2,1.106 |
| Tile | 1,7 Hz | 2,9.106 | 1,6 Hz | 2,8.106 |
| HEC | 1,2 Hz | 2,1.106 | 0,9 Hz | 1,6.106 |
| FCal | 0,3 Hz | 5,2.105 | 0,2 Hz | 3,5.105 |

- 5 June 2003

## Beam Halo Interesting Events ?

**Snakes :**
**	****are there for E******** > few hundred GeV (~0.01 Hz, 2.10****4**** integrated).**
**	******** ****cell mapping? calibration?**

- 5 June 2003

## Beam-GasCollisions

****** ****Beam on gas interactions occurring inside Atlas cavity**
**In Pythia : shoot p(7 TeV) on p(rest), switch all QCD ON, distribute vertices uniformly along z (****±****23 m around IP)**
**Normalization : **
**use ********(pH), ********(pC), ********(pO)...******** ********(pp)****×****A****0.7****; inelastics only ; **
**	****combine into CH4, CO...**
**Use residual gas pressure, as for Halo**
**Beam current = 1/200 of nominal, as for Halo**
**Atlsim**

- 5 June 2003

## Beam GasTypical (!) Event 

- 5 June 2003

## Beam GasRates in Atlas - 1

**Collisions (essentially minimum bias):**
**±****23 m :    ****	****~1,2.10****5**** / s  (integrated : 2,1.10****11****)**
**±****3 m :****	****	****~1,6.10****4**** / s  (1,9.10****10 ****; ID size)**
**±****20 cm : ****	****~1,1.10****3**** / s  (1,9.10****9**** ; ID soft accept.)**
**Particles : consider ****±****3 m window, and ask p****T****>1 GeV**
**********particles in total**
****** ****:    5,6.10****8**

- 5 June 2003

## Beam GasRates in Atlas - 2

- Neutral

- Charged

- 5 June 2003

## Open Issues

**Still not clear : rate of hard muon bremsstrahlung in the calorimeters?**
********* ******needs dedicated simulations ; will also check analytical formulae***
********* ******horizontal ************’s in EMB (and vertical ones in EMEC) : clustering?***
**Clarify hardware limits of trigger (Muon system for Halo, Calorimeters for Beam-Gas)**
**Halo muons : single TGC doublet trigger seems possible**
***	******	******	******     *****Calorimeter trigger?**
**Beam Gas : optimize signal to noise in FCal. Reinvestigate EM for completeness. Other possibilities?**
**Reconstruction:**
**Non pointing tracks**
**“****Wrong” timing, especially in drift detectors**
**Tracks going in “opposite” directions**
**Unusual detector connections**
**... ****and more **

- 5 June 2003

## First glance on reconstruction

**- 3 M cosmic muons entering ATLAS hall**
**- 300 events with signals in pixels**
**- 276 reconstructed tracks in MuSpec(Muonbox)**
**- 257 reconstructed tracks in InDet(xKalman)**
**Software needs to be able to reconstruct objects of arbitrary orientation**
**Muon system : muonbox has already run on many different geometries**
**Calorimeters : need modified clustering**
**ID : iPatRec succeeds in |z0| < 20 cm. Extend to ****∞!**

**lg(P****T**** ****muon)**

**lg(P****T**** ****muon)**

**p****T ****reconstructed**

**p****T ****reconstructed**

**Muon Spectrometer**

**Inner Tracker**

- 5 June 2003

## Beam Haloreconstruction issue

**Useful at start-up (first signals)**
**Also complementary during normal data taking :**
**1 such track every 500****th**** bunch crossing (~10****7**** / day after normal LVL1). Quantify**

- 5 June 2003

## Beam HaloTrigger issues - 1

**Unfortunately, tracks like this one       are lost!**
**	****No LVL1...**
**To trigger, we need **
**a hard ******** in the calos (too rare?)**
**a low-pT muon trigger (+ bend in EC Toroïd to reach EMC or ID)**
**Other ways?**

- 5 June 2003

## Beam GasTrigger issues

-  How to trigger?
-  EM clusters : ET > 2 GeV
-  Few Hz
- FCal energy : Etot > 15 GeV
-   		 Few 101 Hz
-  Is this above noise?

- 5 June 2003

## Cosmic: Summary

**Working cosmic ********G3 (atlsim) MC for ATLAS**
**Different generators**
**4-vectors samples of muons entering cavern**
**ZEBRA event files for offline studies**
**Rates seem to be large enough for initial electronics shake-down**
**Dead channel maps, electronics+DAQ checks, etc.**
**To-do:  triggers and offline reconstruction ...**
**Simplified trigger studies:****  have input already for LVL1 RPC (Gianpaolo Carlino, Leandro Nisati, Stefano Veneziano) and Tiles (Alan Watson), and also from Nick Ellis**
**Full trigger studies: ****switch to full ATHENA trigger simulations, currently under development**
**Many issues for both triggers and reconstruction due to non-pointing, out of time tracks must be studied**
**Studies:  reconstruction, alignment, calorimeter calibration ...**

- 5 June 2003

## Beam-Halo: Summary

**So the raw rates are very promising indeed. They have a **large, common** uncertainty (details of startup scenario)**
**Normal trigger conditions are costly for inner systems. A few guesses (lower bounds, to that respect): **
**Beam Halo : ~10****8**** tracks in MDT, ~10****5**** in ID**
**Beam Gas : ~3.10****6 ****tracks in ID**
**Fruitful ongoing discussions with P.Loch, M.Wielers, N.Ellis, A.Watson, A.Nisati...**
**Reconstruction issues**
**Standard code has some efficiency, but huge factors to gain**
**Fruitful ongoing discussions with Saclay (muonbox) and R.Hawkings (iPatRec)**

- 5 June 2003

## Back-up Material

- 5 June 2003

## In progress: refined description 

**Ground density variation with depth**
**Suspension halls**
**Other caverns (USA15, US15)**
**Being implemented by R.Soluk and J.Pinfold in consultation with CERN civil engineers**
**Can be used for later simulations**

- 5 June 2003