pileup background rejection
DESCRIPTION
Fast Timing Detectors for FP420. FPF420@UTA. WHO?. UTA ( Brandt ), Alberta (Pinfold), Louvain (K.P.), FNAL (Albrow) + SACLAY (Royon), Stoneybrook (M. Rij). WHY?. Pileup Background Rejection. Ex, Two protons from one interaction and two b-jets from another. How?. Compare z-vertex - PowerPoint PPT PresentationTRANSCRIPT
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Pileup Background Rejection
Ex, Two protons from one interaction and two b-jets from another
Fast Timing Detectors for FP420
z=c(TR-TL)/2
z (mm) =0.21 t (psec)(2.1 mm for t=10 psec)
WHO?UTA (Brandt), Alberta (Pinfold), Louvain (K.P.), FNAL (Albrow)
+ SACLAY (Royon), Stoneybrook (M. Rij)
WHY?
How? Compare z-vertex for SVX with TOF
How Fast? 10 psec -> x40 to x30 rejection
FPF420@UTA
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The Detectors : 1) GASTOF
http://www.fynu.ucl.ac.be/themes/he/ggamma/Cherenkov/
(Louvain)
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GASTOFAdvantages:• Presents little material to beam• Extremely fast
Disadvantages:• No segmentation• Long
5 psec
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8 fused silica rods in z (my fused silica!)
Mike’s idea
Jaak’s drawing
The Detectors : 2) QUARTIC
proton
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Fused Silica Bars
• 9 cm bars• Some converted to mini-bars
60 psec
Spread in timing as f()
since n()
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206
6
4
4
~ 60
~ 10
p
Fused Silica
Air light guide (Jim’s)(Aluminium box, or mylar lined plastic)
Taper 6 4 (4 is a guess)(Crude “Winston Cone”)Match to
photocathode“sweet spot”
(mini-bar at 50 deg to p)
UTA simulations showed this solution superior to long bars
Sketch of Mini-bar Solution
dimensions in mm,not to scale
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MCP-PMT
2.54 cm2.54 cm
9.0 cm
3.7 cm
4.7 cm
1.53
cm
2.54
cm
50º2.57
cm
6.4 cm
1.97cm
top view
side view
top view (photo)
QUARTIC Preprototype
beam
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QUARTIC (V2)Advantages:• Segmentation (8 x 4)• CompactDisadvantages:• More material• Not as fast
20 psec
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Baseline Plan1 GASTOF Lots of silicon 2 QUARTICs
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T958• Fermilab Test beam experiment to study fast timing
counters for FP420 (Brandt spokesman)
• Used prototype/preprototype detector with expensive or Louvain-made amplifiers and NIM/CAMAC discriminator/TDC to test concept
• Sporadic mostly parasitic running Aug 12- Sep 14 (primary user Sep 7-10, 14)
Time resolution for the full detector system:1. Intrinsec detector time resolution2. Jitter in PMT's3. Electronics (AMP/CFD/TDC)
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First TB Initial Results
<70 psec/Gastof (2500V)>90% efficiency
G1-G2For QUARTIC bar at 2300VGet 110 psec after correctingfor variable height in bar(compared to 90 psec forG at same voltage);Efficiency typically .5 to .6/bar,low of .2, high of .9, at least part of dependence due to CFD performance
For events with a few bars on see anticipated√N dependence
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Upgrade for T958 Phase II
• New detector prototypes
• New electronics
• Improved DAQ
• Improved alignment
• Automated analysis and database routines, to allow instant and easier analysis
• Improved tracking
March 7-20
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Burle 8x8 MCP-PMT25 um pore
Amplifier :HamamatsuOrtecPhillips
Constant Fraction DiscriminatorOrtec 934(9307)
TDC(Phillips 7186)
T958 Electronics
SMA SMA Lemo
Phase I:
Phase II:
10 um Burle or 6 um Hamamatsu
New boards (Louvain/Alberta)
Phase III:
HPTDC
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Extrapolating
Suppose we did no better than first test beam:67 psec/GASTOF +8bars *.6 eff at 110, this would give 40 psec track measurement or about ~x10 background rejection.
Suppose (40,40,30) for QUARTIC (Elec,MCPMT, detector) (64 psec/bar), and .75 efficiency gives 26 psec for one QUARTIC alone, combined with a GASTOF (elec=40,tube=20,det=10) of 44 psec, gives 22 psec track (x18).
Ultimately QUARTIC might be (20, 15, 20) but lets assume limit of (25,25,25) gives 11 psec for 2 QUARTICS + GASTOF (15,10,5) gives 18 psec -> total <10 psec
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Louvain Electronics:
• First CFD prototype produced and WORKING!!! Designed a NIM multi-channel board with remote control thresholds(directly from LabView using RS232)
• New VERY fast (14 GHz BW) amplifiers from Mini-Circuits show very good characteristics Note: One POSITIVE signal output
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Q1=Q 10um tubeQ11-Q18=12mm barsQ21-Q28=15mm barsQ33-Q36=90mm bars
Q2=R 25 um tubeR11-R18=12mm barsR21-R28=15mm bars
21 11 31
22 12 31
23 13 33
24 14 34
25 15
26 16
27 17
28 18
. .
MCP-PMT layout
. .
beam
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Pedro
Sean
Tomek
Andrew
Luc
Shane
FEBRUARY| MARCH M T W TH F S SU M T W TH F S SU M T W TH F S SU M T W TH F S SU M T26 27 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Personnel Chart/ Time at Fermi
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GASTOF Stand
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First Results from TB2
QUARTIC Extremely promising 90% efficiency,<70 nsec/bar!
Unfortunately, the results were a mirage caused byCoherent noise
Furthermore GASTOF2 inefficient and leaks
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Coherent Noise!
If a row gets blasted, whole tubeground oscillates, 3 nsec later
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Coherent Noise!
~3 nsec
time
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Table shifted 12 mm, to move extra bars out of beam
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How to proceed?
Grounding other bars at connector did not helpNeed new tube to fix problem
Took data with table offsetTook data with scope in remote mode
See following talks