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
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
The Detectors : 1) GASTOF
http://www.fynu.ucl.ac.be/themes/he/ggamma/Cherenkov/
(Louvain)
GASTOFAdvantages:• Presents little material to beam• Extremely fast
Disadvantages:• No segmentation• Long
5 psec
8 fused silica rods in z (my fused silica!)
Mike’s idea
Jaak’s drawing
The Detectors : 2) QUARTIC
proton
Fused Silica Bars
• 9 cm bars• Some converted to mini-bars
60 psec
Spread in timing as f()
since n()
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
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
QUARTIC (V2)Advantages:• Segmentation (8 x 4)• CompactDisadvantages:• More material• Not as fast
20 psec
Baseline Plan1 GASTOF Lots of silicon 2 QUARTICs
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)
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
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
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
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
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
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
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
GASTOF Stand
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
Coherent Noise!
If a row gets blasted, whole tubeground oscillates, 3 nsec later
Coherent Noise!
~3 nsec
time
Table shifted 12 mm, to move extra bars out of beam
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