background rejection activities in italy francesco longo university and infn, trieste, italy
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Gamma-ray Large Area Space Telescope. Background Rejection Activities in Italy Francesco Longo University and INFN, Trieste, Italy [email protected] On behalf of the “North-East” INFN group - PowerPoint PPT PresentationTRANSCRIPT
DC2 prep meeting June 27 2005 F.Longo et al. 1
GLAST LAT Bkg Rejection Italy
Background Rejection Activities Background Rejection Activities in Italyin Italy
Francesco LongoUniversity and INFN, Trieste, [email protected]
On behalf of the “North-East” INFN group thanks in particular to R.Rando, O.Tibolla, Y.Lei, G.Busetto and P.Azzi (University and INFN Padova)
Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope
DC2 prep meeting June 27 2005 F.Longo et al. 2
GLAST LAT Bkg Rejection Italy
Bkg Rejection activityBkg Rejection activity
• Starting from “simple cuts”• Collection of Bkg Rejection documentation • Understanding IM cuts (DC1 variables and cuts)• Classification Trees in R • New recent developments• Ready for new data• More Info: http://sirad.pd.infn.it/glast/ground_sw/dc2.html
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GLAST LAT Bkg Rejection Italy
““By hands” cutsBy hands” cuts
• First iteration using already suggested cuts • Look into Merit Tuple to find efficiency of rejection and gamma
acceptance• Reference docs (Atwood):
– “Instrument response studies” – “Post rome background rejection”
• Datasets:– DC1 prep background ntuples – DC1 prep gamma Merit nutple
• Divide events in particle type: gamma(signal), gamma(bkg), electron+positron, protons
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GLAST LAT Bkg Rejection Italy
Calorimeter categoriesCalorimeter categories
• Definitions: – No cal: CalEnergySum<5. || CalTotRLn≤2
– Low Cal: CalEnergySum>5. && CalTotRLn>2
– Med Cal: CalEnergySum>350. && CalTotRLn>2
– High Cal: CalEnergySum<3500. && CalTotRLn>2
– “Good Energy” events: “good_energy” = (EvtEnergySumOpt-MCEnergy)/MCEnergy
|”good_energy”| ≤ 35%
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GLAST LAT Bkg Rejection Italy
Signal events splitSignal events split
ALL Total No Low Med High
all 722594314226
(43.4%)
122081
(17%)
114224
(15.8%)
172063
(23.8%)
good81139
(66.4%)
94869
(83%)
142082
(83%)
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GLAST LAT Bkg Rejection Italy
Background events splitBackground events split
ALL Total No Low Med High
e 746232649293
(87%)
93933
(13%)
1139
(0.2%)
1867
(0.3%)
p 1165277608568
(52%)
284425
(24%)
178084
(15%)
94200
(8%)
288491276358
(96%)
10066
(3.5%)
1227
(0.4%)
840
(0.3%)
GOOD Low Med High
e 60093 (64%) 854 (75%) 1365 (73%)
p 35407 (12%) 10914 (5.7%) 21033 (22%)
5185 (51.5%) 797 (65%) 459 (55%)
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GLAST LAT Bkg Rejection Italy
““Tree” cutsTree” cuts
• Using IM xml file in classification • Develop a “Node” structure parsing the xml IM output• Check of cuts
DC2 prep meeting June 27 2005 F.Longo et al. 9
GLAST LAT Bkg Rejection Italy
ID
predicate
predicateID
0/1
CT approachCT approach
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GLAST LAT Bkg Rejection Italy
All Total No Lo Med Hi
(all) 722,594 314,226 122,081 114,224 172,063
(good)64,110
(20.4%)
86,190
(70.6%)
90,201
(79.0%)
138,793
(80.7%)
Signal events splitSignal events split
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GLAST LAT Bkg Rejection Italy
Starting with Classification TreesStarting with Classification Trees
• Use of R program – rpart (recursive partitioning)• Searching to optimize “goodCal”• For each step rpart reports the cost-complexity of the tree, the
number of splits, the relative error and finally the error that it obtains from a process of cross validation, with the corresponding sigma.
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GLAST LAT Bkg Rejection Italy
Classification Trees with rpartClassification Trees with rpart
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GLAST LAT Bkg Rejection Italy
Classification Trees with rpartClassification Trees with rpart
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GLAST LAT Bkg Rejection Italy
Classification Trees with rpartClassification Trees with rpart
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GLAST LAT Bkg Rejection Italy
Classification Trees with rpartClassification Trees with rpart
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GLAST LAT Bkg Rejection Italy
One Tree per E binOne Tree per E bin
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GLAST LAT Bkg Rejection Italy
One Tree per E binOne Tree per E bin
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GLAST LAT Bkg Rejection Italy
One Tree per E binOne Tree per E bin
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GLAST LAT Bkg Rejection Italy
Classification Trees with RClassification Trees with R
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GLAST LAT Bkg Rejection Italy
rpart Classificationrpart Classification
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GLAST LAT Bkg Rejection Italy
rpart Classificationrpart Classification
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GLAST LAT Bkg Rejection Italy
Error costsError costs
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GLAST LAT Bkg Rejection Italy
Error CostsError Costs
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GLAST LAT Bkg Rejection Italy
Error CostsError Costs
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GLAST LAT Bkg Rejection Italy
Random ForestRandom Forest
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GLAST LAT Bkg Rejection Italy
Random ForestsRandom Forests
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GLAST LAT Bkg Rejection Italy
Random ForestsRandom Forests
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GLAST LAT Bkg Rejection Italy
Random ForestsRandom Forests
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GLAST LAT Bkg Rejection Italy
rForest packagerForest package