Automatic Track Follow Program • A program to trace a given set of tracks automatically – Event location for PEANUT and OPERA – DONUT “not-located” events Koichi Kodama Aichi University of Education DONUT meeting 2005/05/28
Automatic Track Follow Program A program to trace a given set of tracks automatically –Event location for PEANUT and OPERA –DONUT “not-located” events.
Dec 20, 2015
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Automatic Track Follow Program
• A program to trace a given set of tracks automatically– Event location for PEANUT and OPERA
– DONUT “not-located” events
Koichi KodamaAichi University of EducationDONUT meeting 2005/05/28
( )シート中心部 ビーム有
1
10
100
1000
3 4 5 6 7 8
PH
0.1s
ec/v
iew
0.40.30.20.10.05
low noise require existence of micro tracks on both sides ( base track ) high efficiency scan at lower PH threshold
Base Track Recognition
Low PH scan takes timerestricted scan in
position and in angle space
At least a micro track should be detected in one of 2 sides of a sheet by Normal PH scan.
The other side are checked with LOW PH threshold scan for its existence if it is not found by Normal PH scan
Idea for base track recognition in a plate
Algorithm for Point Scan
Input : position and angle of a track to be found
Scan on both surfaces with Normal PH threshold
A Base Track exists ?( allowed distortion < 50mrad )
A Micro Track exists in either side ?
Found
Not Found
Scan on the other side with LOW PH threshold
A Base Track exists ?( allowed distortion < 50mrad )
YES
NO
YESNO
Found
Not FoundNO
YES
Test with OPERA emulsion sheet
1mm Pb
2GeV pi-5x103/cm2
Point scan with this algorithmNormal PH threshold = 8Low PH threshold = 6
Sample : 537 tracks found in 4 sides ( pl.51A & pl.50A )4mm x 3mm area
pl.51A
pl.50A
Micro TracksUP side
Micro TracksDown side
Base Tracks
Efficiency @ sqrt(chi2/ndf)<3
This algorithm 0.985 ( 527 )U only 0.933 ( 501 )D only 0.944 ( 507 )Both U&D 0.881 ( 472 )
evaluated with 537 tracks
Base Track PH
Plate to Plate Connection
1. A set of tracks to be followed are given.
2. Find alignment between plates• 200micron x 200micron area scan for DONUT• Choose 10 tracks among given tracks
and require >5 tracks to match
3. Check existence of all tracks• Connection judged at Z in the middle• Multiple candidates are kept
Test with OPERA type brick
1mm Pb
2GeV pi-5x103/cm2
follow down
1mm Pb
Sample : 537 tracks found in 4 sides ( pl.51A & pl.50A )4mm x 3mm area
skipfollow down
search window+/- 16micron+/- 20mradfor 1 plate jump
Last Found Plate by OXX rule
Plate # 51 50 49 48 47 46 45 44 43 42 41 40
Last
found
plate
0 0 3 1 2 2 0 1 2 3 3 8 512
For 1mm thick Lead, int ( high energy protons ) = 0.6% thus … int ( high energy pions ) ~ 0.6% x 2/3 = 0.4%537 x 0.4% = 2.1
search window+/- 16micron+/- 20mradfor 1 plate jump
search window+/- 16micron+/- 20mradfor 1 plate jump
Multiple Connection
Test with DONUT not located event
Scan Back 5246 tracksfound on CS ( both sides ) & SS ( down only )
16mm x 15mm < 200mrad
ECC200
Last Found Plate by OXX rule
Plate # 1 2 3 4 5 6 7 8
Last connected plate
270 195 48 6 5 23 1 105 3821
search window+/- 16micron+/- 20mradfor 1 plate jump
Problem in Scanning
search window+/- 16micron+/- 20mradfor 1 plate jump
Multiple Connection
Summary
• Base Track recognition algorithm works.– Efficiency ~ 0.98 possible for OPERA type sheet
• Track follow program works.– ~1 sec/track for Point Scan– 1000 tracks corresponds to ~30 min/sheet
• Good filter program is needed
to suppress grow up of paths to follow.
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