Primo (e ultimo ?) giorno di fascio a LHC

Nuovo Logo di CMSvalido almeno fino allaprossima primavera:

Beam Splash: ~2.109 protons on collimator ~150 m upstream of CMSECAL- pink; HB,HE - light blue; HO,HF - dark blue; Muon DT - green; Tracker Off

CMS Week Sep08 4

Other Distributions: Beam Dumped in Coll.

Energy in ECAL (EE-, EB, EE+)

CMS Week Sep08 5

First Events: Beam going through CMS

Beam Pickup (ch1) CMS Beam Condition Monitors (ch 3, 4) Point 5 Control Room

CMS Centre Meyrin

Halo Muons in CSCs and HB

First LHC Beam in DT System

DT and first beams: beam splash17 events induced by beam 1 dump on the collimators observed in run 61642

DT are far from being the best tool to detect first beams events.

Max number of hits/TDC = 16 in the DAQ. For splash events all TDC are fired -> >300 hits in inner stations.

No segment reconstruction if > 50 hits -> no segments reconstructed in inner stations.

100% of the MB1chambersilluminatedin all 17 events

10/04/23 7

MB2 Occupancy

MB3 Occupancy

MB4 Occupancy

Phi asymmetry

Correlation DT – EB energy

Beam halo in DT

DT and first beams:beam halo

10/04/23 15

MB1 occupancy: # digis/SL

--- All SLs--- r-ϕ SLs--- r-z SLs

beam halo muonscross few cells of r-ϕSLs but many cells in r-z