ams - ecal jan 7 th -8 th, 2003 page 1 f. pilo - siena university/ infn pisa update on stand alone...
TRANSCRIPT
AMS - ECALJan 7th-8th, 2003 Page 1
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Update on stand alone ECAL trigger
S. Di Falco, M. Incagli, F. Pilo, G. Venanzoni
AMS - ECALJan 7th-8th, 2003 Page 2
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Trigger algorithms
Results on photon efficiency and trigger rate
Trigger robustness (against gain fluctuation, ...)
First results on electrons
OUTLINEOUTLINE
AMS - ECALJan 7th-8th, 2003 Page 3
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
In the previous presentation a trigger algorithm has been described. This will be called “ANDAND” algorithm.
Due to the possible problems related to the low threshold values and to the rigid “AND” logic,we decided to develope a different more flexible algorithm which will be called “MIXMIX”.
Trigger algorithmsTrigger algorithms
AMS - ECALJan 7th-8th, 2003 Page 4
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
The AND trigger algorithmThe AND trigger algorithm
thresholds on 6 superlayers:
Low energy trigger:
ANDAND of four superlayers (2,3,4,5) ++ X/Y directions cut + + mean density cut.
High energy trigger:
ANDAND of four superlayers (4,5,6,7) ++ X/Y directions cut.
Global trigger:
low energy trigger OROR high energy trigger
Superlayer Thr(MeV) Superlayer Thr(MeV)
2 20 5 50
3 50 6 400
4 100 7 230
AMS - ECALJan 7th-8th, 2003 Page 5
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
p 1.0% (47 Hz)
Eg(GeV) 0o-10o 10o-20o
1 45% 43%
2 83% 82%
5 92% 90%
10 97% 96%
20 98% 98%
50 95% 96%
100 99% 96%
300 96% 94%
Results of the previous presentationResults of the previous presentation
AMS - ECALJan 7th-8th, 2003 Page 6
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
New higher thresholds
Thresholds on 6 Superlayers
Thresholds logic: 3 AND 4 AND (2 OR 6) AND (5 OR 7)
New X/Y directions cut:
No density cut, No high energy trigger
2.25 10
1.6< 10
1.15< 4
bMAXNhit6+Nhit7
A new trigger algorithm: MIX logicA new trigger algorithm: MIX logic
120
100
100
Thr(MeV)
7
6
5
Superlayer
1004
1003
1002
Thr(MeV)Superlayer
AMS - ECALJan 7th-8th, 2003 Page 7
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
New proton sampleNew proton sample
In the previous presentation the protons sample was generated
“ECAL focused”. This was not completely correct mainly because of the
secondary particles produced in detector interactions which were not
taken into account (a 30% effect was estimated). A new sample of
protons generated isotropically on the surface of the “standard box”
(390 x 390 x 390 cm3) surronding the detector was used.
The rate is defined as:
where NBOX is the number of protons generated on the box, ABOX is the
acceptance of the standard box (286.7 sr m2 ), is the flux and NTRG is
the number of events which are selected by our stand alone trigger.
BOXBOX
TRG
N
NRate A
AMS - ECALJan 7th-8th, 2003 Page 8
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Proton FluxProton Flux
The flux is taken from Choutko’s note ‘Over Cutoff Proton Flux…’ (May 2000) and it corresponds to the polar orbit.
1830
AMS - ECALJan 7th-8th, 2003 Page 9
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
EpKIN
(GeV)
Flux
(Hz sr-1 m-2)
BOX
(10-4) rate
(Hz)
0.265-0.5 352 0.46 4.64 0.71
0.5-1.5 1060 0.24 7.29 1.52
1.5-2.5 502 0.47 7.76 1.01
2.5-3.5 267 0.87 6.67 0.69
3.5-4.5 160 1.37 6.26 0.55
4.5-5.5 103 1.33 3.92 0.35
5.5-6.5 70 1.57 3.14 0.26
6.5-7.5 50 2.05 2.91 0.20
7.5-8.5 36.7 1.66 1.74 0.14
8.5-9.5 27.8 1.98 1.58 0.11
9.5-10.5 21.6 2.30 1.42 0.09
10.5-11.5 17.4 2.46 1.23 0.08
EpKIN
(GeV)
Flux
(Hz sr-1 m-2)
BOX
(10-4) rate
(Hz)
11.5-12.5 14.0 2.22 0.89 0.06
12.5-13.5 11.6 2.36 0.78 0.05
13.5-14.5 9.61 2.64 0.73 0.04
14.5-15.5 7.97 2.68 0.61 0.04
15.5-16.5 6.83 2.54 0.50 0.03
16.5-17.5 5.89 3.16 0.53 0.03
17.5-18.5 4.96 2.90 0.41 0.02
18.5-19.5 4.28 3.24 0.40 0.02
19.5-20.5 3.87 3.62 0.40 0.02
>20.5 41.1 4.20 4.96 0.24
TOTAL 57.8 HzThresholds only: 482 Hz
Updated Results for the AND trigger algorithmUpdated Results for the AND trigger algorithm
AMS - ECALJan 7th-8th, 2003 Page 10
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
EpKIN
(GeV)
Flux
(Hz sr-1 m-2)
BOX
(10-4) rate
(Hz)
0.265-0.5 352 <0.01 <0.3
0.5-1.5 1060 0.05 1.52 0.61
1.5-2.5 502 0.17 2.45 0.58
2.5-3.5 267 0.36 2.76 0.46
3.5-4.5 160 0.77 3.52 0.41
4.5-5.5 103 0.91 2.68 0.30
5.5-6.5 70 1.35 2.70 0.24
6.5-7.5 50 1.45 2.06 0.17
7.5-8.5 36.7 1.58 1.66 0.14
8.5-9.5 27.8 1.81 1.44 0.10
9.5-10.5 21.6 1.90 1.17 0.12
10.5-11.5 17.4 2.14 1.07 0.10
EpKIN
(GeV)
Flux
(Hz sr-1 m-2)
BOX
(10-4) rate
(Hz)
11.5-12.5 14.0 1.86 0.75 0.08
12.5-13.5 11.6 2.48 0.82 0.07
13.5-14.5 9.61 2.04 0.56 0.06
14.5-15.5 7.97 2.44 0.56 0.05
15.5-16.5 6.83 2.26 0.44 0.04
16.5-17.5 5.89 2.62 0.44 0.04
17.5-18.5 4.96 2.60 0.37 0.03
18.5-19.5 4.28 2.84 0.35 0.03
19.5-20.5 3.87 3.66 0.41 0.03
>20.5 41.1 3.42 4.04 0.31
TOTAL 31.8 Hz
Results for the MIX trigger algorithm: rejectionResults for the MIX trigger algorithm: rejection
Thresholds only: 188 Hz
AMS - ECALJan 7th-8th, 2003 Page 11
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
AND vs MIX trigger algorithm: rejectionAND vs MIX trigger algorithm: rejection
AMS - ECALJan 7th-8th, 2003 Page 12
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
In the previous presentation trigger efficiency was calculated by
requiring photon trajectory intersection with the TOF’s and the 5th ECAL
superlayer.
In the present study the photons intersecting the external ECAL columns
have not been considered (common definition with Sapinski).
New photon selectionNew photon selection
AMS - ECALJan 7th-8th, 2003 Page 13
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
E(GeV) 0o-10o 10o-20o
1 16% 14%
2 83% 81%
3 94% 94%
4 94% 94%
5 95% 94%
10 95% 95%
20 97% 96%
50 97% 96%
100 98% 97%
300 97% 95%
E(GeV) 0o-10o 10o-20o
1 45% 43%
2 83% 83%
3 90% 89%
4 90% 89 %
5 93% 90%
10 97% 97%
20 98% 98%
50 95% 97%
100 99% 95%
300 96% 94%
OLD NEW
AND vs MIX trigger algorithm: efficiency AND vs MIX trigger algorithm: efficiency
AMS - ECALJan 7th-8th, 2003 Page 14
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
AND vs MIX trigger algorithm: efficiency (II) AND vs MIX trigger algorithm: efficiency (II)
AMS - ECALJan 7th-8th, 2003 Page 15
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
MIX trigger algorithm robustness: gain fluctuationMIX trigger algorithm robustness: gain fluctuation
Proton rate changes from 31.8 (no smearing) to 30.8 Hz (sigma = 20%)
Gain fluctuation was simulated by MC, applying a gaussian spread to all the PMT outputs, with sigma chosen between 2% and 20%.
fluctuation changes event by event
same fluctuation for all the events
AMS - ECALJan 7th-8th, 2003 Page 16
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
MIX trigger algorithm robustness: gain shiftMIX trigger algorithm robustness: gain shift
Proton rate changes from 31.8 (no gain shift) to 18.9 Hz (gain shift= -30%), to 50.1 Hz (gain shift +30%)
The effect of a systematic gain shift between +30 and –30% was studied
negative gain shift positive gain shift
AMS - ECALJan 7th-8th, 2003 Page 17
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Proton rate changes from 31.8 (no broken PMT’s) to 29.1 Hz in the worse case.
• No broken PMT � 1 broken PMT
Effect of broken PMT’s: efficiency is the average of 20 different configurations of broken PMT’s.
• No broken PMT 5 broken PMT’s
• No broken PMT 10 broken PMT’s
MIX trigger algorithm robustness: broken PMT’sMIX trigger algorithm robustness: broken PMT’s
AMS - ECALJan 7th-8th, 2003 Page 18
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Proton rate changes from 31.8 (no broken PMT’s) to 29.6 Hz in the worse case.
• No broken PMT � 1 broken PMT
Effect of broken PMT’s in the superlayer 3 and 4: efficiency is the average of 20 different configurations of broken PMT’s.
• No broken PMT 5 broken PMT’s
• No broken PMT 10 broken PMT’s
MIX trigger algorithm robustness: broken PMT’s (II)MIX trigger algorithm robustness: broken PMT’s (II)
AMS - ECALJan 7th-8th, 2003 Page 19
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Proton rate changes from 31.8 (no broken PMT’s) to 37.0 Hz in the worse case.
• No broken HV ch. � 1 broken HV ch.
HV failure was simulated by increasing the output of some PMT’s by a factor of 10: efficiency is the average of 20 different configurations.
• No broken HV ch. 5 broken HV ch.’s
• No broken ch. 10 broken ch.’s
MIX trigger algorithm robustness: HV failuresMIX trigger algorithm robustness: HV failures
AMS - ECALJan 7th-8th, 2003 Page 20
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
ee sample selection: 3 out of 4 TOF planesextrapolated trajectory: - do not intersect ACC - crosses 5th SL (not at edges)
ECAL fast trigger (thresh. only) to recover ECAL fast trigger (thresh. only) to recover vetoed evetoed e
TOF:TOF: 3 out of 4 TOF planes
TOF+ANTI:TOF+ANTI: 3 out of 4 TOF planes AND
NACC=0
TOF+ANTI+ECfast:TOF+ANTI+ECfast: 3 out of 4 TOF planes AND
(NACC=0 OR ECthresholds OK)
backsplash effect
AMS - ECALJan 7th-8th, 2003 Page 21
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Summary and OutlookSummary and Outlook
Two different algorithms were studied for the stand alone trigger:
“AND”: good low energy gamma efficiency also to 1 GeV, but low
threshold and rigid “AND” logic
“MIX”: good efficiency E≥2 GeV, higher thresholds (~100 MeV),
robusteness.
For MIX algorithm the proton rate is 30 Hz for the AMS01 proton flux
in the worst latitude condition.
Study against gain fluctuations, shifts, broken PMT’s,..., shows
sensible differences in efficiency only for energy below 5 GeV (30% in
the worse case).
Backsplash problem is well fixed.
AMS - ECALJan 7th-8th, 2003 Page 22
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Trigger analog circuit simulation: Jitter StudyTrigger analog circuit simulation: Jitter Study
Simulated circuit: follower + (10x) amplifier + comparator
Two tested amplifier: LMH6643, OPA690, no SQ but in the AMS list
The OPA690 amplifier requires more power (+2 mA). The overall
trigger power consumption is increased by ~1 Watt.
Using OPA690 the response delay for a small input signal is reduced
(from 60 to 25 ns)
AMS - ECALJan 7th-8th, 2003 Page 23
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Jitter Study: Jitter Study: LMH6643LMH6643
Input signal: 2mVDelay: ~60 ns
Input signal: 2mVDelay: ~10 ns
AMS - ECALJan 7th-8th, 2003 Page 24
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Jitter Study: OPA690Jitter Study: OPA690
Input signal: 2mVDelay: ~25 ns
Input signal: 2mVDelay: ~5 ns
AMS - ECALJan 7th-8th, 2003 Page 25
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Minimum total energy threshold of 220 MeV: good efficiency at
low energy but trigger rate sensitive to low energy proton flux
Minimum PMT threshold of 20 MeV ≳ MIP signal (~16 MeV):
could it increase fast trigger Jitter?
AND logic rigidity could reduce trigger robustness (efficiency
dependence on PMT gains and PMT failures)
Open Problems for the AND trigger algorithmOpen Problems for the AND trigger algorithm
AMS - ECALJan 7th-8th, 2003 Page 26
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Accettanza dell’ECAL
Calcolo geometrico. Ogni faccia conta p (flusso solo entrante):
2p (0.648 x 0.648) + 4p (0.648 x 0.1665)= 4 sr m2
Verifica ‘empirica’. Flusso isotropo su una sfera di raggio 1 m:
‘Acettanza dinamica’. Generando isotropicamente 105 fotoni da
2 GeV sulla scatola standard (3.9x3.9x3.9 m3) e guardando gli
eventi con ETOT>120 MeV sull’ECAL si trova:
AECAL(dall’alto) = 2.18 0.08 sr m2
(Corinne gives 2.2 sr m2 )
AECAL(dal basso) = 2.06 0.08 sr m2
2msr 4sfera
ECALsferaECAL N
NAA
AMS - ECALJan 7th-8th, 2003 Page 27
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Calcolo del rate di protoni
Per tenerne correttamente conto dei secondari si considerera’
l’efficienza non rispetto agli eventi nell’ntupla ma rispetto a quelli chiesti
al Montecarlo (TRIG card) usando come rate quello ottenuto
moltiplicando il flusso per l’accettanza della scatola standard (ABOX=
286.7 sr m2 ):
Il fattore 2 dovuto al fatto che si considerano solo particelle dall’alto e’
incluso in NTRIG (il Montecarlo genera comunque anche le particelle dal
basso ma non le scrive nell’ntupla)
BOXTRIG
trigger FlussoN
NRate A
AMS - ECALJan 7th-8th, 2003 Page 28
F. Pilo - Siena University/ INFN PisaF. Pilo - Siena University/ INFN Pisa
Effetto dei secondari
Generando isotropicamente 106 protoni con spettro energetico
cosmico con 0.5<p<200 GeV/c sulla scatola standard (3.9x3.9x3.9 m3)
si trova:
ApECAL(dall’alto) = 2.72 0.08 sr m2
ApECAL(dal basso) = 2.07 0.08 sr m2
L’eccesso del 35% nel flusso di particelle dall’alto e’ da imputare ai
secondari
Per tenerne conto si considerera’ l’efficienza non rispetto agli eventi
nell’ntupla ma rispetto a quelli chiesti al Montecarlo usando come rate
quello ottenuto moltiplicando il flusso per l’accettanza della scatola
standard