Minimum Bias Trigger Public Results

Introduction

Approved plots that can be shown by ATLAS speakers at conferences and similar events. Please do not add figures on your own. Contact the responsible project leader in case of questions and/or suggestions. Follow the guidelines on the trigger public results page.

2015 Data

MBTS Trigger Efficiency Fig. 2a in https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2015-028/	to be added
MBTS Collision Timing Relative timing of the rising edge of the 50 ns trigger signal from the different Minimum Bias Trigger Scintillator (MBTS) counters in units of 25 ns Bunch Crossings (BC) with respect to the bunch crossing position where beams were colliding in ATLAS. 12 MBTS counters are located at z = +3560 mm from the Interaction Point (IP) (A side) and 12 at z = -3560 mm from the IP (C side). Counters 0-7 form an inner ring around the beam pipe while counters 8, 10, 12 and 14 form an outer ring at larger radius. 13 TeV collision candidate events were selected with a two sided coincidence MBTS trigger. For physics operation, the trigger signal is combined with the LHC fill pattern recovering the signal from counters whose rising edge is one BC early. The in-time BC is highlighted with a red border. MBTS PMTs were at a nominal setting of 830 V, NIM model 715 constant fraction discriminators were used to issue the trigger signal with a 200 mV threshold. The discriminators variable threshold range is 25-1000 mV.	png pdf
MBTS Beam Splash Timing Relative timing of the leading edge trigger signal from different Minimum Bias Trigger Scintillator (MBTS) counters in units of 25 ns Bunch Crossings (BC) with respect to an independent, single-sided calorimeter trigger on outgoing splash particles (which had passed the interaction point). 12 MBTS counters are located at z = +3560 mm from the Interaction Point (IP) (A side) and 12 at z = -3560 mm from the IP (C side). Counters 0-7 form an inner ring around the beam pipe while counters 8, 10, 12 and 14 form an outer ring at larger radius. Data were taken with 35 beam-2 (top fig) and 30 beam-1 (bottom fig) induced splash events on 07/04/2015. The in-time BC is highlighted with a red border. MBTS PMTs were at a low setting of 570 V, NIM model 715 constant fraction discriminators were used to issue the trigger signal with a 200 mV threshold. The discriminators variable threshold range is 25-1000 mV.	png pdf png pdf

2009 Data

MBTS time difference The difference between the time measured by the Minimum Bias Trigger Scintillators (MBTS) A side and that measured by the MBTS C side for three runs. One with two beams, one with beam 1 only and one with beam 2 only.	png pdf
MBTS Energy distribution The total raw energy deposited in the MBTS counters is shown for events with a time difference |t_A-t_C|<7.5 ns (blue), and for events with |t_A-t_C|>7.5 ns (red).	png
MBTS Multiplicity distribution The MBTS counter multiplicity is shown for events with a time difference |t_A-t_C|<7.5 ns (blue), and for events with |t_A-t_C|>7.5 ns (red). The last curve has events with a timing which is not compatible with collision timing, including those events that have an undefined time difference (ie multiplicity <2). A MBTS hit is defined if its raw energy is above 0.18pC.	png