21/06/12 Lar Week - Noise Burst Induction 1

Noise Burst induction with HV ramps

Thomas Serre (CPPM)

Thanks to:

E. TiouchichineE. MonnierB. Trocme

21/06/12 Lar Week - Noise Burst Induction 2

Noise Burst- Definition : - a Noise Burst is spotted when a high amount of Calo cells is noisy in an event. - 2 algorithms to spot Noise Burst : => LarNoisyROAlg_std : 5 FEBs with 30 channels with q factor > 4000 => LarNoisyROAlg_SatTight: more than 20 channels with |E| > 1GeV and q =65535

- Typical shape of a Noiseburst

- plotting Ecell > 800 MeV => In stream CosmicCalo => in EMECA

- ring in η ~1.4 - η > 2.5 - Noisy cells around Φ = 0

- Is there a correlation between HV and NBs ?

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Noise Burst Study- Campaign of HV ramp down / ramp up

- Atlog : https://atlasop.cern.ch/elog/ATLAS/ATLAS/196838 - Testing correlation between ramp dowm / ramp up and Noise bursts in LAr = > radiation of noise along the HV lines ? - 3 sets of HV channels in EMECA were used = > ramped down by 800V = > ramped up by 2V/s

- Sets of HV channel

1 HV sets in eta x phi =[1.6,2.1]x[-2.6,-1]

1 HV sets in eta x phi =[1.6,2.1]x[-2.6,-1]

1 HV set in eta x phi =[1.5,2.3]x[-0.5,1.5]

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Before ramps : LB 0 - > 16

- Nothing done during these LBs

- Plotting number of cells with |E| > 3σnoise

=> in the differents EMEC-A layers => integrated over the Lbs

- no collisions in this data

- No noisy cells spotted and no noise burst as expected

- Rate of Noise Bursts per LB : =>

LArNoisyRO_Std_rate = 0

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1st ramp : LB 17 -> 25

- Nothing done during these Lbs - As expected, no noise burst spotted

- 1st HV set ramped down in a region not affected by Nbs

- Red hatching = ramped down region

- in s0, allmost no noisy cells. - in s1, Noisy cells at eta < 1.5 where no HV ramped down !

- in s2 and s3, noisy cells around HV ramped down and around eta ~ 1.4 - 1.5

- Rate of Noise Bursts per LB : =>

LArNoisyRO_Std_rate =1.55556

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2nd ramp : LB 30 -> 37

- 1st HV set ramped down - in s1, only noisy cells at eta < 1.5 where no HV ramped down ! - in s2 ans s3, noisy cells around HV ramped down and around eta ~ 1.4 - 1.5

LArNoisyRO_Std_rate =2.75

- 2nd HV set ramped down in a region not affected by NBs

- in s0, more noisy cells

- in s1, Noisy cells at η < 1.5 and at η > 2.5

- same “ η-Φ region” ramped down and same number of HVlines => but allmost 2 times more noisy cells than in 1st trip ! (=> maybe cosmic rays cosmic rays between LBs 30 and 32 ) - Rate of Noise Bursts per LB : =>

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1st partial ramp up LB 39 -> 60

- (Partial) ramp up of the 2 first HV sets

=> channel in B0, B1 and B2 not ramped up (see atlog for details and back up slides for channels) => only channels in B3 B4 B5 ramped up

- few noisy cells

- 2nd HV set ramped down - same region, same number of HV lines allmost 2 times more noisy than 1st ramped down ... why ?

LArNoisyRO_Std_rate =0 - Rate of Noise Bursts per LB : =>

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3rd trip : LB 151 -> 159

- (Partial) ramp up of the 2 sets - allmost no Nbs during ramp up !

- 3nd HV set ramped down in a region affected by NBs

- Again, a clear ring in 1.4 < η < 1.6 of noisy cells in the 3 EMEC layer => same noise burst shape as previously => doesn t depend on the region where the trip occurs

=> LArNoisyRO_Std_rate =2.7 - Rate of Noise Bursts per LB :

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2nd ramp up : LB 163 -> 171

- 3nd HV set ramped down in a region affected by NBs

- Again, a clear ring in 1.4 < η < 1.6 of noisy cells in the 3 EMEC layer => same noise burst shape as previously => doesn t depend on the region where the trip occurs

- Rate of Noise Bursts per LB :

- 3nd HV set partially ramped up - same problem for the first 2 sets : => Only channels in B3, B4 and B5 ramped up.

- No noisy cells at all !

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Noise Burst evolutionBeginning of theramp LB 150 -> 153 End of the ramp LB 154 -> 159

- Noise burst start in a particular region : (η,Φ) = (1.45,-0.5)

- Then it “propagates” to η>2.5 and over all Φ

- Let s check in the 2nd trip if it s the same thing

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Noise Burst evolutionBeginning of the ramp LB 32 -> 34 End of the ramp LB 34 -> 37

- Noise burst start at least in a particular region η ~1.45

- Then it “propagates” to η>2.5 and over all Φ

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Noise Burst per partition

- Does a HV ramp down in a partition create NoiseBursts in others ? LB 150 -> 159 (3rd trip)

- No noise in barrel induced - Noise in HEC -A and also some noise in EMEC-C and HEC-C

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Noise Burst per partition

- Does a HV ramp down in a partition create NoiseBursts in others ? LB 17 -> 25 (3rd trip)

- No noise in barrel induced - Noise in HEC-A and HEC-C

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Conclusion

- Is there a correlation between HV and NBs ?

=> Yes, one can induce NoiseBurst by ramping HV lines => wherever the ramping is done => same shape as in Data

- Propagation of Noise Burst

=> Start in a η region within [1.4,1.5] then propagates to higher η (> 2.5) => A noise Burst in EMEC – A propagates to HEC-A but not to barrel => to be confirmed that noise is induced in EMEC – C and HEC – C

- Further Studies => redo the same thing without partial ramp up ... channels in B0, B1 and B2 didn t ramp up => check in other partitions (EMEC-C) => vary the ramp speed and check effect on noise burst

- New ramps campains

=> Tuesday 19/06 (done, ATLOG 209208) => Friday 22/06