Data Taking Plans for Cosmics and VG Photons Sept 27, 2004 Gary Godfrey SLAC
Preliminary results of separation from data tracks 1.Outline 2.Comparison of cosmics in both…
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Transcript of Preliminary results of separation from data tracks 1.Outline 2.Comparison of cosmics in both…
Preliminary results of separation from data tracks
1. Outline2. Comparison of cosmics in both
bricks3. and tracks4. Separation with NN5. Conclusion, TBD
OPERA Collab. Meeting GS May 2005
Thomas Waelchli LHEP Uni Bern
•Data from 2nd PSI-TB June 2004•Pion beam: 202MeV/c, ( contamination <1%)•Muon beam: 120MeV/c, (e contamination <5%)•2 bricks ( 30 cells, : 50 cells)
•Goal: –Follow tracks until they stop–Develop simple method for identification based on ‘normal scanning’ (16 layers/emulsion)–Fill NN with MCS angles, scattering coord., (dE/dx)
•2x5cm2 (), 3x3cm2 () scanned, outside beam-spot•Tracks reconstructed with FEDRA
–Using 200MeV/c for Kalman filter–Standard instrumental precision
1. OUTLINE
T. Waelchli, OPERA Collab. Meeting GS May 2005
T. Waelchli, OPERA Collab. Meeting GS May 2005
FINDING COSMICS…CUTS: {((nseg>10 && n0<=3) || npl>(N-3)) && t.eFlag>=0
&& track starts in 1st or 2nd emulsion&& (nseg-10) < 0.6}N: number of cells in brick
t.eP
t.eP
t.eP > 0.7
2. COSMICS IN BOTH BRICKS
T. Waelchli, OPERA Collab. Meeting GS May 2005
segi segi+1
iXi
Pb
beam
i
Average MCS angle:
av=i*cos(i)/nseg)
Average MCS coordinate: Xav=Xi*cos(i)/nseg)
Xav Xav same in and brick
Instrumental precision ca. 3mmuon brickpion brick
0muon brickpion brick
avmuon brickpion brick
T. Waelchli, OPERA Collab. Meeting GS May 2005
2. COSMICS IN BOTH BRICKS-brick is shorter larger angle of incidence 0 possible
av ca. 2mrad smaller in -brick possible thru ….
But av identical No bias
av/0
muon brickpion brick
3.AND TRACKS
707 227
T. Waelchli, OPERA Collab. Meeting GS May 2005
CUTS: {nseg>=10 && n0<=3 && npl<(N-3) && t.eFlag>=0 && t.eP<0.3 && track starts in 1st or 2nd emulsion&& (nseg-10) < 0.6}N: number of cells in brick
T. Waelchli, OPERA Collab. Meeting GS May 2005
3.AND TRACKS
avmuonspions
Xavmuonspions
av and Xav only average definednumber of cells before the end of a track.
-Good separation already ‘from eye’
-bla
-bla
-bla
T. Waelchli, OPERA Collab. Meeting GS May 2005
3.AND TRACKSs.eVolumeav
s.eVolumeav
s.eVolumeav
s.eVolumeavmuonspionsmuons
cosm.
pionscosm.
cosm. ()cosm.
....
NN with 2 (3) input neurons
INPUT LAYER: 2 (3) neurons filled with av , Xav and (eVolav)
HIDDEN LAYER with 2 (3) neuronsOUTPUT LAYER with 1 neuron:
“0” for muon“1” for pion
typical NN output
T. Waelchli, OPERA Collab. Meeting GS May 2005
Xav
IN HID OUT
orav
eVolav( )
Many different configurations tested:
•Varying number of cells
•Omitting cells at end of a track
Best efficiency is 85% using 9 cells, omitting the last.
Conclusion and TBD• Separation capability of data tracks up to
85% with less than 10 available segments
• TO BE DONE:• Improve / fine-tune simulation• (include dE/dx into NN)• Check mixing/ambiguities of FEDRA
reconstructed tracks as function of density with simulation
T. Waelchli, OPERA Collab. Meeting GS May 2005