NA61 – 2009 data takingA. Marchionni, ETHZ

2009 data taking detector upgrades• TPC readout electronics, new trigger system FPGA based,

larger size BPDs, extension of the Forward TOF

thin target data taking from August 13 to August 25 morning

long target data taking: from August 25 evening to September 3 morning

Thin target data takingTriggers and prescaling factors

Trigger-1 (T1) : beam trigger (S1*S2*Vbar*Cbar*CED) Trigger-2 (T2) : interaction trigger (T1*S4bar) Trigger-3 (T3) : interaction trigger without veto counters Trigger-4 (T4) : interaction w/o beam-PID trigger (S1*S2*Vbar*S4bar)

T1/T2 = 15% T3/T2 = 2% T4/T2 = 5%

T2/Beam Target IN: 7.01%T2/Beam Target OUT: 1.64%

2007T2/Beam Target (IN-OUT): (5.36±0.01)%

Multiple triggers running in parallel with the new trigger system

Accumulated statistics

In addition, taken ~100K events target holder data

~5.5M events, corresponding to 4.4M interaction triggers

Beam Profiles

Preliminary

Boris Popov

~20% less efficiency than in 2007with very preliminary alignment and thresholds

Preliminary

Boris Popov

~5 points less on average than 2007due to TPC noise

TOF

Preliminary

Boris Popov

dE/dx distributions

Preliminary

Boris Popov

Kinematical distributions

Preliminary

Boris Popov

Beam momentum

Preliminary

Boris Popov

2007

2009

Long target data taking

~3.5M events, corresponding to >2.5M beam particles hitting the long target

T1 : beam trigger S1*S2*V1pbar*Cbar*CED 21.6%T2 : beam trigger (outer target ring) S1*S2*V1pbar*Cbar*CED*S3 30.9%T3 : beam trigger (core of target) S1*S2*V1pbar*V0bar*Cbar*CED*S3 35.6% T4 : beam trigger – no PID S1*S2*V1pbar*S3 11.8%

Triggers

2009 Long Target event

Jeremy Argyriades

Conclusions

2009 data taking thin target: 4.4M interaction triggers long target: >2.5M beam particles hitting the target

Preliminary look at thin target 2009 data data quality look OK accumulated statistics seems OK