60 likes | 253 Views
Dynamic Pedestal Problem. Amplifier peaks 134 nsec after muon passes For tpeak too low pedestals are incorrect At tpeak<184 nsec trouble starts. Look at Amanda’s collision muon sample. Q. t. Theory:.
E N D
Dynamic Pedestal Problem • Amplifier peaks 134 nsec after muon passes • For tpeak too low pedestals are incorrect • At tpeak<184 nsec trouble starts Look at Amanda’s collision muon sample Q t Theory: Sample 9 Sample 1 Sample 2 Sample 4 Sample 4 wqnok3 5 … ped 0 ped 1
Collision Muons Theory >1% error at tpeak=165 nsec tpeak (nsec)
CMSSW Software modification will mitigate problem float ped = (sca(1)+sca(0))/2 if(sca(1)-sca(0)>3*3.2)ped=sca(0); • sqrt(2) worse pedestal resolution • not a long term solution
>1% pedestal error Software Fix >1% pedestal error tpeak (nsec)
Still studying hardware side Measured 7 bx 5bx is 2 bx later Configuration parameter shift ? Firmware update ?