coherent noise task update

8/18/2019 Coherent Noise Task Update

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Study of Coherent Noise in SiliconStrip Detector at CMS

Atiq ur RahmanDr. Ashfaq Ahmad

National Centre for Physics, Islamabad

4/2/16 1Coherent Noise Task


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Motivation

Frameor!

Measurement of Noise

Parameteri"ation of coherent noise

Conclusion


Outlines


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CMS Tracker overview

4/2/16 Coherent Noise Task 4


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Module %y&es



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Motivation

%o measure coherent noise in silicon stri& detector at

CM$.

Develo& a criteria'method to fla( noisy modules in

$ilicon $tri& %rac!er.

%he corrections derived is intended to be used durin(trac! reconstruction

)ould reduce the chance of reconstruction of noisy

clusters and hel& to (et more &recise A#D data for

so&histicated analysis.

64/2/16 Coherent Noise Task


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*sin( CM$$)++-+-/&atch D0M and $i$tri& &ac!a(es

Root

Identification criteria

Fec1crate'slot'rin('CC*'M#D*23'22D'I-C etc .

4''-'56'-'7 vs DetID

Data1 Pedestal Run


Framework


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Normali"ed Noise difference

Normali"ed noise difference is assumed to have

a nominal value hen there is no correlated

noise and &oints deviatin( from this line are

considered to be in correlation or anti/correlation

as a first test.

=


Noise Calculation Cont!


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Noise Modes

De&endin( u&on the different trends of noises

hich e encounter in $ilicon stri& trac!er, edefine noise modes

Normal mode

)in( sus&ect Dead or lo noise mode

)eird mode

Normal is one hich is normal trend in trac!er,

in( mode is >in( ? sha&ed noise trend , Dead

mode is none res&ondin( and havin( "ero noise

mode



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Normal Mode



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Correlation coefficients for normal mode



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"in# Mode



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Correlation Plots for "in# Mode



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Paraolic or $uadratic fit

$i"e of >A? decide hether the &arabola is ideor narro.

Positive >A? shos it is u&ard.

>@? is the (eneral slo&e in equation of line.

>C? shift in the &arabola i.e u& or don

minB/:@'-A;

minB/

:min, min; is verte of the &arabolas

=



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Parameteri%ation of correlations coefficients



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Map for Parameter &


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Map for the Parameter '


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Map for +)min*



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()min* vs &

Only the large value of A do not ensure that thechannel will have large correlation. TheParameter “C” play a decisive role in additionto A . We deicide about the correlated channelwith only !min" not with C or A individually.4/2/16 23Coherent Noise Task


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()min* vs +)min*

Lager values of !"in# is not hurting

our results4/2/16 24Coherent Noise Task


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& vs +)min*

All the channels having large value of A parameteralways lies in Physical range of the AP#. $o weshould not worry about the non%physical strips.&asically ' such channels have a almost linear

distribution of correlation coe(cients. That is why weare ettin the lar e )!min".4/2/16 25Coherent Noise Task


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+)min* vs C

All the anomalous values of the parametersmostly coming in the Physical range of AP#

$trips.4/2/16 28Coherent Noise Task


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Channels in the tail of !min" after the chi%$*uare cut As we have very small windowfor y!min" in the distribution !min"+%.,-

Channels in the %ails of :min; for 2eft+fit


Channels in the Tails of ()min* for ,eft fit


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Channels in the Tails of ()min* for ,eft-fit


Channels in the tails of ()min* for ,eft fit


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C a e s t e ta s o ) * o e t- t


Channels in the tails of ()min* for ,eft fit


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Channels in the tails of ()min* for ,eft-fit



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$olution to nois% an& &ea& 'hannel (ro)le"

As we were getting the noisy as well as thecorrelated channels in the tails of the y!min"which were contaminating our results forcorrelated channels. have /agged the noisy or

dead strips as not 0tted to our general*uadratic!as well linear model". We haveobtained the distribution of chi s*uare and got agood cut for channels.

n rest of the channels we get only correlatedchannels in the tails of !min".



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Chi s*uare &istri)ution )efore an&


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Chi s*uare &istri)ution )efore an&after 'ut

12

The 'hannels in the tail of Left Chi+$*uare)efore the 'ut are (resente& in later sli&es, -t'an .ag even a s"all "issing of stri(s


e c anne s n e a s o e %


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e c anne s n e a s o e $*uare

we have got almost all the noisy and deadchannels in the tails of chi%s*uare which were in

the tail of the !min" before the chi%s*uare cut. The Chi s*uare de0nition is highly sensitive forthe channels which have small number of noisystrips.

The *uadratic 0t model is a general 0t and linear0t is a special case of *uadratic 0t with parameter“A” e*ual to 3ero.

All the non%Physical )!min" have nominal valuesof parameter A and !min". They do not hurt ourresults. This indicate that they have astonishinglylinear distribution of correlation coe(cients.


M f Chi S


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Map for Chi.S$uare


Channels in the tails of chi.S$uare for


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16

Channels in the tails of chi S$uare for

,eft-fit


Channels in the tails of chi/$quare for 2eft+fit


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Channels in the tails of chi.S$uare for ,eft-fit


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89

$ -



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Staility of the ()min* in SST TI'


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y ) *

Does this y:min; is stable in the other $ub detectorsE

TI'


T0C1


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T0C


TO'


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TO'


Conclusions


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Conclusions

%he :min; is used to decide about the correlation of the channels. No

any individual &arameter can be used to quantify the correlation. >A? and

>C? are both sensitive but lar(e value of >A? may not decide that thischannel is sensitive for correlation. $imilarly , the only value of >C? do

not ensure us about correlation only.

@ut in the case of terribly linear distribution of correlation coefficients, e

can say that the >C? &arameter becomes same as :min;.

%he chi/$quare value for the quadratic fit (ives a (ood criteria to

eliminate the noisy channels. %he channels hose chi/square value for

the quadratic fit is (reater than to are all noisy.

%he values of :min; ill be used for fine tune of cluster char(e.

%his criteria can be used to correct the CM$ data and can reduce the

chance of noisy clusters. ere is our ti!i &a(e htt&s

1''ti!i.cern.ch'ti!i'bin'vieauth'CM$'$i$tri&NoiseCorrelation
https://twiki.cern.ch/twiki/bin/viewauth/CMS/SiStripNoiseCorrelationhttps://twiki.cern.ch/twiki/bin/viewauth/CMS/SiStripNoiseCorrelationhttps://twiki.cern.ch/twiki/bin/viewauth/CMS/SiStripNoiseCorrelationhttps://twiki.cern.ch/twiki/bin/viewauth/CMS/SiStripNoiseCorrelation

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