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Standard AnalysisNtuple Variables

Introduction

The variables from the Analysis Ntuple are presented here grouped by tool. Within each tool, variables are arranged roughly according to their position in the ntuple.

Unless otherwise noted, energy is in MeV, length is in mm, and angle is in radians. Also, unless otherwised noted, the null value, that is, the value in the ntuple when there is no calculated value for a given variable, is zero.

The variables may be of type Int, Unsigned int, Float, Double or String. Currently, for reasons of history, most are floats, even those that take only integer values.

(A "string" is a null-terminated character array. The default value is "_".)

AdCValsTool Variables

Notes

Variable Type Description

AcdTileCount INumber of tiles fired
AcdRibbonCount INumber of ribbons fired
AcdTotalEnergy FTotal energy deposited in ACD Tiles
AcdRibbonEnergy FTotal energy deposited in ACD Ribbons
AcdTileIdRecon ITile identifier that was pierced by the reconstructed track. A value of 899 (N/A) is the default and denotes that no ACD tile was intersected by a reconstructed track.
AcdRibbonIdRecon (fixme) IRibbon identifier that was pierced by the reconstructed track. A value of 899 (N/A) is the default and denotes that no ACD ribbon was intersected by a reconstructed track.

AcdActiveDist3D FActive Distance most likely to give a veto. Corresponds to Act. Dist. that is greater than a set an energy dep. min. distance and has the largest pulse height
AcdActiveDist3DErr (fixme) FError on most likely veto active distance of any track to the edge of any tile
AcdActDistTileEnergy FThe deposited energy in the corresponding hit tile
AcdActDistTrackNum FTrack number of track which was used for AcdActiveDist3D. Track numbering starts at zero; best track number is zero; -1 means no track

AcdRibbonActDist (fixme) FLargest active distance to any ribbon (considered as a straight line of no thickness)
AcdRibbonActDistErr (fixme) FError on the smallest active distance to any ribbon (considered as a straight line of no thickness)
AcdRibbonActLength(fixme) FLength along ribbon where point of closest approach occured. 0 is center of ribbon + going towards +x or +y side of ACD
AcdRibbonActEnergyPmtA (fixme) FThe deposited energy in the A PMT of the corresponding hit ribbon
AcdRibbonActEnergyPmtB (fixme) FThe deposited energy in the B PMT of the corresponding hit ribbon

AcdCornerDoca FMinimum Distance of Closest Approach of best track to the corner side gaps
AcdTkrHoleDist (fixme) FMinimum Distance of Closest Approach of any track to any of the tile screw holes
AcdTkrRibbonDist FMinimum Distance of Closest Approach of any track to any ribbons that cover gaps
AcdTkrRibbonLength (fixme) FLength along ribbon where point of closest approach occured. 0 is center of ribbon + going towards +x or +y side of ACD.

AcdTkr1ActiveDist FLargest active distance from track 1 to the edge of any tile
AcdTkr1ActiveDistErr FError on largest active distance from track 1 to the edge of any tile
AcdTkr1ActDistTileEnergy FThe deposited energy in the corresponding hit tile

AcdTkr1RibbonActDist FLargest active distance to any ribbon (considered as a straight line of no thickness)
AcdTkr1RibbonActDistErr FError on the smallest active distance to any ribbon (considered as a straight line of no thickness)
AcdTkr1RibbonActLength FLength along ribbon where point of closest approach occured. 0 is center of ribbon + going towards +x or +y side of ACD
AcdTkr1RibbonActEnergyPmtA FThe deposited energy in the A PMT of the corresponding hit ribbon
AcdTkr1RibbonActEnergyPmtB FThe deposited energy in the A PMT of the corresponding hit ribbon

AcdTkr1CornerDoca FMinimum Distance of Closest Approach of best track to the corner side gaps
AcdTkr1HoleDist FMinimum Distance of Closest Approach to best track to any of the tile screw holes
AcdTkr1RibbonDist FMinimum Distance of Closest Approach to best track to any ribbons that cover gaps
AcdTkr1RibbonLength (fixme) FMinimum Distance of Closest Approach to best track to any ribbons that cover gaps

AcdVtxActiveDist FLargest active distance from vertex extrapolation to the edge of any tile
AcdVtxActiveDist_Down FLargest active distance from vertex extrapolation to the edge of any tile, down-going side of tracks
AcdVtxActDistTileEnergy FThe deposited energy in the corresponding hit tile
AcdVtxActDistTileEnergy_Down FThe deposited energy in the corresponding hit tile, down-going side of tracks

AcdNoSideRow[0...3] FHit Tile counts for side row [0...3] that have energy > TileCountThreshold (= .8)

CalMipValsTool Variables

Variable Type Description
CalMipNum FTotal number of found mip-like tracks in the Cal
CalMip[X/Y/Z]0 F[x/y/z] coordinates of the energy centroid of the best track
CalMip[X/Y/Z]Dir F[x/y/z] direction cosines of the best track
CalMipD2edge FDistance of the best track from the nearest edge of the Cal
CalMipArcLen FLength of the best track (mm)
CalMipEcor FMean vertical-eq1uvalent energy (MeV) of the best track, obtained by averaging the pathlength-corrected energies in each layer
CalMipEcorRms FRMS of CalMipEcor
CalMipChi2 FChi-squared of the direction fit for the best track (combination of least squares in XZ and YZ planes)
CalMipErm Ftotal energy (MeV) contained in a cylinder of 1 Moliere radius around the best track

CalValsTool Variables

Variable Type Description
CalEnergyRaw FSum of the raw energies in all the crystals. Includes estimate of missed energy due to zero-supression. This replaces the variable CalEnergySum.
CalEnergyCorr FCal Energy corrected layer-by-layer for edges and leakage. This replaces the variable CalEneSumCorr.
CalLeakCorr FLeakage correction: this is the contained fraction of the total energy after edge corrections.
CalEdgeCorr FEffective layer-by-layer edge correction mainly due to the gaps between Cal modules; multiplicative
CalTotalCorr FGlobal total correction. Includes effect due to dead material; multiplicative
CalCsIRLn FTotal radiation lengths in crystals, integrated along the event axis (line connecting the first hit in the tracker to the CAL energy centroid)
CalTotRLn FTotal radiation lengths in the CAL, integrated along the event axis.
CalCntRLn FRadiation lengths integrated along the event axis, up to energy centroid
CalLATRLn FTotal radiation lengths integrated along the event axis (including the tracker).
CalDeadTotRat FRatio of radiation lengths in dead material to CalTotRLn
CalDeadCntRat FRatio of radiation lengths in dead material up to energy centroid, to CalCntRat
CalTPred FModel-predicted energy centroid in radiation lengths
CalDeltaT FDifference between measured and predicted energy centroids
CalTwrEdge FDistance of the entry point of the best track from the tower boundary, measured at the top of the CAL.
CalLATEdge FClosest distance of track 1, projected to the top of the CAL, to the edge of the CAL layer, taking non-square shape into account. This is essentially the old merit skirt variable.
CalEdgeEnergy FThe sum of the raw energies in each crystal for which the energy centroid is within _deltaEdge (currently 50 mm) of the outside edge of one of the outside CAL modules. This is an attempt at a "anti-coincidence counter" for the CAL.
CalTwrEdgeCntr FDistance of the energy centroid from the nearest tower boundary.
CalGapFraction FApproximate fraction of the shower volumn which falls in inter-tower gaps.
CalTrackSep FDistance between impact points of two best tracks at CAL front face; zero if only one track
CalTrackDoca FDistance between the projected vertex (or track if only one track) and the energy centroid, evaluated at the z of the centroid.
CalTrackAngle FAngle between "gamma" direction in the tracker and direction of the CAL "track"
CalELayerN, N=0,7 FEnergy deposited in layer N of the CAL
CalLyr0Ratio FRatio of CalELayer0 to CalEnergyRaw
CalLyr7Ratio FRatio of CalELayer7 to CalEnergyRaw
CalBkHalfRatio FRatio of total energy in back half of CAL (layers 4-7) to CalEnergyRaw
CalXtalsTrunc FNumber of CAL Xtals with > 1 of CalEnergyRaw (see CalXtalRatio)
CalXtalRatio FRatio of number of Xtals with energy > 1% of CalEnergyRaw to total number of struck Xtals in the event.
CalXtalMaxEne FMaximum energy found in a single Xtal
CalLongRms Frms of the average of the 1st and 3rd shower moments. Indicates the length of the measured shower along the shower axis.
CalLRmsAsym FThe asymetry of the 1st and 3rd shower moments. This should be close to zero. Because of ordering of moments it is slightly ... (??)
CalTransRms Frms of transverse position measurements.
CalMIPDiff FDifference between measured energy and that expected from a minimum-ionizing particle
CalMIPRatio FRatio of measured energy to that expected from a minimum-ionizing particle
Cal[X/Y/Z]Ecntr FEnergy centroid in [x/y/z]
Cal[X/Y/Z]Dir F[x/y/z] direction cosine of CAL "track"
Cal[X/Y]0 F[x/y] position of where the first track hits TOP of Calorimeter
CalTopGapDist FDistance of TOP position from an intermodule gap
CalTrkXtalRms FFor this and the next three variables, a measure of the rms spread of the crystals in the calorimeter around the projection of the first track. They differ by the weighting and crystal count. This one is the rms of the DOCAs of all crystals with repect to the projected track
CalTrkXtalRmsE FSame as the previous, but weighted by the deposited energy in each crystal
CalTrkXtalRmsTrunc FSame as the first, but excludes the crystals with the largest DOCAs. Default is to remove 10% of the crystals, with the number of crystals included rounded to the nearest integer
CalTrkXtalRmsETrunc FSame as the previous, but weighted by the deposited energy in each crystal
CalRmsLayerE FRms of deposited energy (normalized to rad. lengths traversed, and to average energy deposited) for all the layers with > 5% of deposited raw energy and at least 0.5 rad lengths of predicted CsI traversed.
CalRmsLayerEBack FSame as above, with layer 0 left out of the calculation
CalNLayersRmsBacj INumber of layers used in the calculation of CalRmsLayerEBack above
CalEAveBack FAverage of normalized eDep excluding layer 0, cuts as for CalRmsLayerE above
CalLayer0Ratio FRatio of layer0 normalized eDep to the average of the remaining layers, cuts as for CalRmsLayerE above
Cal[X/Y]PosRmsLL FEnergy Weighted Rms of the hit crystals in the last layer (layer 7). X is measured across the width of the crystals, Y across the length.
CalCfpEnergy Fenergy reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpChiSq Fchi squared reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpEffRLn Feffective amount of X0 reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpTkrRLn Famount of X0 in the tracker reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpAlpha Falpha (first parameter) reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpTmax Ftmax (second parameter = position of maximum of shower in X0) reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpFitErrFlg Ffit flag reported by the full profile fit (using the tracker direction if there is one, the cal direction otherwise)
CalCfpCalEnergy Fenergy reported by the full profile fit (using the cal direction)
CalCfpCalChiSq Fchi squared reported by the full profile fit (using the cal direction)
CalCfpCalEffRLn Feffective amount of X0 reported by the full profile fit (using the cal direction)
CalCfpCalAlpha Falpha (first parameter) reported by the full profile fit (using the cal direction)
CalCfpCalTmax Ftmax (second parameter = position of maximum of shower in X0) reported by the full profile fit (using the cal direction)
CalCfpCalFitErrFlg Ffit flag reported by the full profile fit (using the cal direction)
Cal[X/Y/Z]Ecntr2 FEnergy centroid in [x/y/z] determined using only the crystal transverse information
Cal[X/Y/Z]Dir2 F[x/y/z] direction cosine of CAL "track" determined using only the crystal transverse information
CalPosDirChisq Fchisquared of fit determination of position and direction using only the crystal transverse information
CalPosDirNLayers Fnumber of layers used during fit determination of position and direction using only the crystal transverse information
CalNSaturated Fnumber of saturated crystals
CalTrSizeCalT[68,90,95,99,100] FTransverse size of shower as function of energy fraction : Cal = using cal position and direction; T = using only crystal transverse information
CalTrSizeCalTL[68,90,95,99,100] FTransverse size of shower as function of energy fraction : Cal = using cal position and direction; TL = using crystal transverse and longitudinal information
CalTrSizeCal2T[68,90,95,99,100] FTransverse size of shower as function of energy fraction : Cal2 = using cal2 position and direction; T = using only crystal transverse information
CalTrSizeTkrT[68,90,95,99,100] FTransverse size of shower as function of energy fraction : Tkr = using tkr position and direction; T = using only crystal transverse information
CalTrSizeTkrTL[68,90,95,99,100] FTransverse size of shower as function of energy fraction : Tkr = using tkr position and direction; TL = using crystal transverse and longitudinal information

EventAuditor Times for Selected Algorithms/Sequences

Times for selected entities are given in seconds. The granularity is ~16msec (60Hz). The variables are named "Aud"+Entity Name. The current default set is:

AudEvent, AudGeneration, AudReconstruction, AudTkr, AudCal2

Note: the time for the first event in a run includes initialization overhead.

EvtValsTool Variables

These are calculated from combinations of the variables from different tools.

NOTE

Variable Type Description
EvtRun UIRun number, copied from the event header NEW: replaces Run in the merit ntuple
EvtEventId UISequence number of event in the run (as generated) NEW: replaces Event_ID in the merit ntuple
EvtElapsedTime DElapsed time in seconds since t0 (for DC1: 18-July-2005, for the future: mission start 1-Jan-2001)
FT1Livetime D(s) Cumulative live time, from start of run, or mission

EvtEnergyCorr FEvent energy formed by adding the corrected tracker energy (TkrEnergyCorr) to the layer-by-layer corrected cal. energy CalEnergyCorr.
EvtEnergyRaw FTkrEnergy + CalEnergyRaw
EvtDeltaEoE F(EvtEneryCorr - McEnergy)/ McEnergy. Was EvtMcEnergySigma
EvtCalEdgeAngle FObsolete; replaced by CalTwrGap
EvtTkrEdgeAngle FObsolete; replaced by Tkr1TwrGap
EvtLogEnergy Flog10 of EvtEnergyCorr, pegged between log10(20) and log10(50,000). Was EvtLogESum
EvtTkr1EFrac FTkr1ConE/EvtEnergyCorr, roughly, fraction of energy carried by best track
EvtVtxKin FThe vertex opening angle compenstated for the energy split between the tracks.
EvtVtxEAngle FVtxAngle*EvtEnergyCorr. Should be approx. constant. However an empirical compensation is provided below (see EvtEVtxAngle)
EvtTkrComptonRatio FRatio of TkrTotalHits to twice the number of layers from the head of the best track to the bottom of the TKR
EvtETkrComptonRatio FEvtTkrComptonRatio, flattened in energy and cos(theta). Was EvtTkrEComptonRatio
EvtPSFModel FPSF expected from simple model; depends only on energy.
EvtETkr1Chisq FTkr1Chisq, compensated for energy and angle.
EvtETkr1FirstChisq FTkr1FirstChisq, compensated for energy and angle
EvtETkr1Qual FTkr1Qual, compensated for energy and angle
EvtTkr1PSFMdRat FRatio of errors from covariance matrix to EvtPSFModel
EvtECalTransRms FCalTransRms, compensated for energy and angle
EvtECalLongRms FCalLongRms, compensated for energy and angle
EvtECalLRmsAsym FCalLRmsAsym, compensated for energy and angle
EvtECalXtalRatio FCalXtalRatio, compensated for energy and angle
EvtECalXtalTrunc FCalXtalsTrunc, compensated for energy and angle
EvtECalTrackDoca FCalTrackDoca, compensated for energy and angle
EvtECalTrackSep FCalTrackSep, compensated for energy and angle
EvtEVtxAngle FEvtVtxEAngle, compensated for energy and angle
EvtEVtxDoca FVtxDOCA, compensated for energy and angle

FT1 Variables

see FT1 definition

Variable Type Description
FT1EventId UIRunNumber*100000 + EventNumber
FT1Energy F(MeV) estimate for energy
FT1Theta, FT1Phi F(deg) reconstructed direction with respect to instrument coordinate system
FT1Ra, FT1Dec F(deg) reconstructed direction in equatorial coordinates
FT1ZenithTheta, FT1EarthAzimuth F(deg) reconstucted direction with respect to local zenith system
FT1L, FT1B F(deg) galactic longitude and latitude of reconstructed direction
FT1Livetime D(s) Cumulative live time, from start of run, or mission
FT1ConvLayer FStarting layer of the best track found in the tracker (Layer 0 is the one closest to the calorimeter.)
FT1ConvPoint[X/Y/Z] FDo not use; no longer filled!

GltValsTool Variables

(Glt = GLAST Trigger)

Variable Type Description
GltWord FTrigger word from the event header, based on digi information (null value: -1) The definition of the bits can be found in TriggerBits.h in the enums package.

b_ROI  =    0x01  ///>  Trottle bit
b_Track=    0x02  ///>  3 consecutive x-y layers hit
b_LO_CAL=   0x04  ///>  single log above low threshold
b_HI_CAL=   0x08  ///>  single log above high threshold
b_CNO  =    0x10  ///>  cover or side veto, high threshold ("CNO")
b_trottle=  0x20  ///>  temporary copy of the ROI bit, for backward compatibilty
b_ACDL =    0x40  ///> set if cover or side veto, low threshold
GltGemSummary FFor Data, a copy of the GEM condtion summary; for MC, the same as calculated from the trigger (digi) information (null value: -1) The bits are defined in GemConditionsSummary.h in the enums package.

Here are the definitions as of GlastRelease v7r2 (They are not expected to change.):

ROI   = 0x01         CNO       =  0x10
TKR   = 0x02         PERIODIC  =  0x20
CALLE = 0x04         SOLICITED =  0x40
CALHE = 0x08         EXTERNAL  =  0x80
GltEventFlags FEvent flags from Ebf
GltTower FId of tower that triggered; if more than one, choose the tower with the highest triggered layer (null value: -1)
Glt[X/Y]Tower F[x/y] index of GltTower (null value = -1)
GltTotal FNumber of possible triggers (a straight-through track in a single tower produces 13 potential triggers
GltNumTowers FNumber of towers which trigger (crossing track)
GltType FNumber of exposed sides for the triggered tower, i.e. 0 = central tower, 1 = side tower, 2 = edge edge tower, 4 = any single-tower setup
GltMoment FDo not use
GltZDir FDo not use
GltEngine IThe engine number corresponding to GltWord
GltGemEngine IThe engine number corresponding to the GltGemSummary
GltEnginePrescale IThe GLT prescale factor for the event
GltGemEnginePrescale IThe GEM prescale factor for the event
GltPrescaleExpired Itrue if the prescale counter expired for this event <trGltSourceGps Itrue if timing comes from the GPS

Celestial Coordinates of the Primary MC Particle

Variable Type Description
McRa, McDec F(deg) reconstructed direction in equatorial coordinates
McZenithTheta, McEarthAzimuth F(deg) reconstucted direction with respect to local zenith system
McL, McB F(deg) galactic longitude and latitude of reconstructed direction

McKludgeValsTool Variables

These variables are supplied as a temporary fix so that ClassifyAlg doesn't crash when it finds them missing

Variable Type Description
McSourceId FUnique integer associated with each MC source type; set to -1
McEnergy Fset to -1
McDirErr Fset to -1
McTkr1DirErr Fset to -1
McDirErrN Fset to -1
McDirErrN1 Fset to -1
Mc[X/Y/Z]Dir Fset to -2

McValsTool Variables

Variable Type Description
McSourceId FUnique integer associated with each MC source type; from McEvent header replaces Mc_src_Id in merit ntuple
McSourceName Sc-string containing the name of the MC source
McNumIncident FNumber of incident particles, usually 1 can be zero to N for test beam
McId FStdHepId of primary (-13 = mu+, 22 = gamma, etc.)
McCharge FCharge of primary
McEnergy FKinetic energy of the generated primary particle
McLogEnergy Flog10(McEnergy)
McEFrac FFraction of incident energy in highest-energy daughter
McOpeningAngle FActual opening angle between the first and second daughters of the promary as generated, (For a primary photon, these will ordinarily be the electron and positron.)
McTkrExitEne FAttempt to calculate the total energy leaving the tracker volume
Mc[X/Y/Z]0 F[x/y/z] coordinate of photon conversion or charged particle origin
Mc[X/Y/Z]Dir F[x/y/z] direction cosine of primary particle
Mc[X/Y]Err F[x/y] (found) - [x/y] (Mc) (Mc position taken at the z of the found vertex or first hit)
McZErr Fz(actual vertex or first hit) - McZ0
Mc[X/Y/Z]DirErr F[x/y/z]dir (found) - [x/y/z]dir (Mc )
McDirErr FAngle between found direction and Mc direction (radians )
McTkr[1/2]DirErr FAngle between direction of [best/second] track and Mc direction (radians)
McAcd[X/Y/Z]Enter FPosition where MC particle enters volume surrounded by ACD
McAcdActiveDist3D FLargest active distance from MC particle relative to ACD hit tiles
McAcdActDistTileId FID of tile with the largest active distance
McAcdActDistTileEnergy FEnergy deposited in tile with the largest active distance

Celestial Coordinates of the Best OnboardFilter Track

Variable Type Description
FilterRa, FilterDec F(deg) reconstructed direction in equatorial coordinates
FilterL, FilterB F(deg) galactic longitude and latitude of reconstructed direction

ObfValsTool Variables

The bit definitions for the output status words are contained in the following files located in the Glast obf external package (starting at obf/B1-0-8/PHY):
  1. Gamma Filter - EFC/GFC_status.h
  2. HIP Filter - XFC/HFC_status.h
  3. MIP Filter - XFC/MFC_status.h
  4. DGN Filter - XFC/DFC_status.h

The ObfXXX and GrbXXX variables are calculated in the ground-software simulation of the onboard flight software.

Variable Type Description
ObfGamStatus, same for Hip, Mip, Dgn IThe 32-bit status word output from the Gamma, Heavy-Ion, Minimum-Ionizing and Diagnostic Filters, resp, as calculated by the OnboardFilter simulator.
ObfGamState, same for Hip, Mip, Dgn IThe 4-bit state word summarizes veto and prescaler states, as calculated by the OnboardFilter simulator.
ObfGamStage IThe "stage" reached by the gamma filter (see the GFC_STAGE definition in EFC/GFC_status.h)
ObfGamEnergy FThe energy in the calorimeter seen by the Gamma Filter
Grb[X/Y]Hits INumber of hits in X (or Y) projection of "best" track
GrbSlp[X/Y] FSlope of "best" track in X or Y projection
GrbInt[X/Y] FIntercept in X-Z or Y-Z projection of "best" track
GrbZ FZ coordinate of "best" track
Grb[X/Y/Z]Dir FDirection cosines of "best" track
GrbMcAngSep FIf MC run, angle to "true" incident particle of "best" track

The FswXXX variables are calculated onboard in flight software. For simulated data, they will be copies of the corresponding ObfXXX variables.

Variable Type Description
FswGamStatus, same for Hip, Mip, Dgn IThe 32-bit status word output from the Gamma, Heavy-Ion, Minimum-Ionizing and Diagnostic Filters, resp.
FswGamState, same for Hip, Mip, Dgn IThe 4-bit state word summarizes veto and prescaler states
FswGamPrescaleIndex, same for Dgn IThe prescaler which expired for this event. Remapped to the order they are applied, counting down from 33.
33 -> input prescaler. Event is ignored by this filter.
32 -> output prescaler. Event is passed by this filter.
31-0 -> "line" prescalers. Only checked when each bit is set.
-1 -> no prescaler expired.
FswGamPrescaleFactor, same for Dgn IThe value to which the relevent prescaler counted before it expired. ie. the number of similar events that were tossed for each one that was kept, the "weight"
FswGamEnergy FSee ObfGamEnergy
FswGamStage ISee ObfGamStage

Pt Variables

These items are added to the merit tuple to give the current instrument orientation

Variable TypeDescription
PtTime D(s) Current time, same as the elapsed time
PtLat,PtLon F(deg) lattitude and longitude
PtAlt F(km) altitude
PtMagLat Fmagnetic latitude
PtPos[3] F(m) current orbit position
PtRax,PtDecx F(deg) equatorial coordinates for orientation of S/C x-axis
PtRaz,PtDecz F(deg) equatorial coordinates for orientation of S/C z-axis
PtSCzenith F(deg) current angle between zenith and S/C z-axis

TkrHitValsTool Variables

Variable Type Description
TkrNumHits ITotal number of TKR clusters
TkrFirstLayer IFirst layer containing a cluster
TkrNumLayersHit ITotal number of hit layers
TkrHitsInLyrNN, NN=(00,17) INumber of clusters in (bi)layer NN (numbered from the bottom of the tracker)

TkrValsTool Variables

Notes:

General variables

Variable Type Description
TkrNumTracks FNumber of tracks found (Maximum is set by TkrRecon, currently 10)
TkrSumKalEne FSum of Kalman energies (see TkrNKalEne, below) for the two best tracks
TkrSumConEne FSum of the energies for the two best tracks, as assigned by the patrec energy tool
TkrEnergy FEnergy in tracker, as determined from linear regression analysis of number of clusters
TkrEnergySum FDeprecated
TkrEnergyCorr FTkrEnergy corrected by TkrEdgeCorr
TkrEdgeCorr FTracker edge correction. This may go away; it's an intermediate quantity
TkrHDCount FNumber of unused clusters in top x-y layer of the best track within a radius of 30 mm, corrected for track angle (Used in PSF analysis and background rejection)
TkrTotalHits FDeprecated. Use TkrSurplusHCInside instead
TkrSurplusHitsInside FNumber of clusters inside an energy- and angle-dependent cone centered on the reconstructed axis of the best track and starting at the head of track 1. Only clusters in layers with at least one x and one y cluster in the tower are counted.
TkrSurplusHitRatio FRatio of the number of clusters outside the cone to the number inside. See TkrSurplusHitsInside
TkrThinHits FNumber of clusters in the above cone in the thin-converter layers
TkrThickHits FNumber of clusters in the above cone in the thick-converter layers
TkrBlankHits FNumber of clusters in the above cone in the no-converter layers
Tkr2TkrAngle FAngle between first and second reconstructed tracks
Tkr2TkrHDoca FDistance between first and second track in the plane of the first hit on the first track. This is most useful if the two tracks are almost parallel, in which case the usual DOCA is poorly measured.

Variables that exist for both best and second tracks

Variable Type Description
Tkr[1/2]Chisq FTrack chisquared
Tkr[1/2]FirstChisq FTrack chisquared for first Tkr[1/2]FirstHits layers
Tkr[1/2]Hits FNumber of clusters in track
Tkr[1/2][First/Last]Layer F[First/Last] layer in track (layer 0 is the bottom of the tracker)
Tkr1FirstGapPlane Fplane number of first gap on track 1 (This and the following X,Y pair can be used to find dead strips)
Tkr1[X/Y]Gap F[x/y] location of first gap on track 1
Tkr[1/2]Qual FTrack "quality": depends on the number of clusters and chisquared of the track. Maximum is currently 64, can be negative if chisqared gets large. This is used primarily to order the tracks during patrec. It's not a good idea to cut on this variable!
Tkr[1/2]Type FThese are the status bits from the trackign, containing information about how the track was found and fitted. See TkrTrack.h in the Event package for the current description. As of GlastRelease v7r2, the status word bits organized as follows:


       |  0   0   0   0  |  0   0   0   0  |  0   0   0   0  |  0   0   0   0   |
        [ Pat Rec Info  ]  [Pass ][ E-Loss] [ Track Energy ]  [Track Fit Status]

        FOUND    = 0x0001,  //Set if track has been "found" by pat rec
        FILTERED = 0x0002,  //Set if track fit filter stage has been run
        SMOOTHED = 0x0004,  //Set if track fit smoother has been run
        REVFILTR = 0x0008,  //Set if track has been reverse-filtered
        CALENERGY= 0x0010,  //Set if track energy from raw calorimeter info
        LATENERGY= 0x0020,  //Set if track energy from TKR+CAL constrained
        USERENERGY= 0x0040, //Set if track energy set by user
        MCENERGY = 0x0080,  //Set if energy from users or from MC truth
        RADELOSS = 0x0100,  //Set if radiative energy loss used (e+/e- fitting)
        MIPELOSS = 0x0200,  //Set if Bethe-Block energy loss used (not e+/e-)
        ONEPASS  = 0x0400,  //Set if the full first pass track fit finished
        TWOPASS  = 0x0800,  //Set if an iteration of the first fit finished
        PRCALSRCH= 0x1000,  //Set if Pat. Rec. used Cal Energy Centroid
        PRBLNSRCH= 0x2000,  //Set if Pat. Rec. used only Track info.
        TOP      = 0x4000,  //Set if track traj. intercepts top tracker plane
        BOTTOM   = 0x8000   //Set if track traj. intercepts first Cal layer

The definitions should be fairly stable.
Tkr[1/2]TwrEdge FDistance from tower edge of initial point (0 is halfway between the towers, increases towards center of tower)
Tkr[1/2]PrjTwrEdge FDistance from tower edge of track extrapolated to the layer upstream of the first layer (See Tkr1TwrEdge.)
Tkr[1/2]KalEne FKalman energy of track 1; this is the energy determined from the multiple scattering along the track (goes like 1/E). Since it is possible to measure a zero scattering angle, which would lead to infinite energy, the minimum measureable angle, which limits the energy to reasonable values
Tkr[1/2]ConEne FEnergy from PatRec energy tool for track 1. The tool computes the total event energy and then partitions it between the first 2 tracks according to their Kalman energies and energy errors

Variables that exist only for best track

Variable Type Description
TkrRadLength FRadiation lengths traversed by the best track. This is from half-way thru the initial converter to the lowest bi-plane in the tracker, whether or not the track actually gets to the end.
TkrTwrEdge FThe average distance of the best track from the "edge" of each tray, weighted by radiation lengths traversed. (The edge is a plane halfway between the towers.
TkrTrackLength FDistance between the start of the best track and the grid, along the track axis.
Tkr1TwrGap FLength of track in nominal intertower gap, currently set to 18 mm. Can be a small as zero if track exits through bottom of tracker, and as large as the intertower gap, if track crosses to adjacent tower.
Tkr1ThetaErr FError on the measurement of theta
Tkr1PhiErr FError on the measurement of phi.
Tkr1ErrAsym FTkr1SXY/(Tkr1SXX + Tkr1SYY)
Tkr1CovDet FDeterminant of the error matrix, but normalized to remove the dependence on cos(theta)
Tkr1S[XX/YY] F[x-x/y-y] element of the covariance matrix; square of error on [x/y]
Tkr1SXY Fx-y element of the covariance matrix; covariance
Tkr1ToTFirst FToT associated with the first hit on best track (All ToT's are adjusted for pathlength in the measuring and non-measuring directions in the strip, and for the strip width.) Note: there is only one ToT per half-plane. If there is more than one hit strip, the highest ToT is stored.
Tkr1ToTAve FAverage ToT for the hits on the best track (See note above.)
Tkr1ToTTrAve FAverage ToT for the hits on the best track, excluding the largest and smallest (See note above.)
Tkr1ToTAsym FAsymmetry between last two and first two ToT's for the best track (See note above.)
Tkr1ChisqAsym FAsymmetry between last two and first two track-segment delta-chisquared's
Tkr1SSDVetoOld FNumber of silicon planes between the top of the extrapolated track and the first plane that has a cluster near the track. Only planes that have wafers which intersect the extrapolated track are considered. No checks for dead strips, etc. are made (yet!). Can be used as a back-up for the ACD.
Tkr1SSDVeto FNew version of the SSD Veto. For this variable, tracks which pass close to a dead plane, buffer-saturated region, inter-wafer gap, gap between towers, or dead strips, do not cause the veto count to be incremented if no cluster is found. This almost certainly overdoes it: a more correct calculation would include the probability for the track to cross the inactive region. (Coming soon!)
TkrVetoPlaneCrossed INumber of planes contributiong to the SSD Veto. This doesn't count the points where a track crosses in a gap.
Tkr1CoreHC FNumber of clusters within a roughly cylindrical region )(default radius 10 mm) around the TrackHits in each plane between the first and last on the best track, excluding the clusters that belong to the track itself
TkrDispersion Fthe RMS of the distances between the 1st track and all others in the event. For tracks which start "above" the first track distance is the 3-D distance For the rest, distance is the doca of the head of the track to the axis of the first track.
TkrUpstreamHC FThe number of clusters in a cylinder (default radius 150 mm) up to 4 layers thick above the head of the first track.
Tkr1CORERatio Fthe ratio of Tkr1CoreHC and Tkr1Hits
Tkr1LATEdge FMinimum distance to any LAT edge of the head of the best track
Tkr1FirstHits FNumber of initial TrackHits used to determine the starting direction
Tkr1DifHits FDifference between the number of x and y clusters associated with track
Tkr1Gaps FTotal number of gaps in track
Tkr1FirstGaps FNumber of gaps in first Tkr1FirstHits layers on track
Tkr1DieEdge FDistance from die (wafer) edge of initial point (0 is halfway between the dies, increases toward center of die)
Tkr1KalThetaMS FMultiple scattering angle (radians) referenced to first layer. The contributions from all the layers in the track are adjusted for the predicted energy in each layer, and weighted accordingly. So the result is sensitive to the particle type and the chosen energy-loss mechanism.
Tkr1[X/Y/Z]Dir FTrack [x/y/z] direction cosine
Tkr1Phi FTrack phi, radians (direction from which particle comes, not particle direction!) range: (0, 2pi)
Tkr1Theta FTrack theta, radians (direction ditto)
Tkr1[X/Y/Z]0 FTrack [x/y/z] position at first hit

Diagnostic SSD Veto Variables (Optional, absent by default)

(Turn on with jO parameter: ToolSvc.TkrValsTool.enableVetoDiagnostics = true;)
Variable Type Description
TkrVetoTrials IDifference between the plane number of the last plane crossed and the first, plus one Any gaps above the last plane are not counted. (This may change soon.)
TkrVetoHitFound INumber of clusters found
TkrVetoUnknown IMissing clusters not ascribable to any inactive area
TkrVetoTower INumber of tower crossings (zero for now, because the propagator doesn't report them)
TkrVetoGapCorner INumber of missing clusters close to a wafer corner
TkrVetoGapEdge INumber of missing clusters close to a wafer edge
TkrVetoBadCluster INumber of missing clusters close to a dead strip
TkrVetoDeadPlane INumber of missing clusters close to a dead plane
TkrVetoTruncated INumber of missing clusters close to a truncated region
TkrVSSDVeto FSame as Tkr1SSDVeto, but for the veto track
TkrVChisq FSame as Tkr1Chisq, but for the veto track
TkrVHits FSame as Tkr1Hits, but for the veto track
TkrVFirstLayer FSame as Tkr1FirstLayer, but for the veto track
TkrVKalEne FSame as Tkr1KalEne, but for the veto track
TkrVConEne FSame as Tkr1ConEne, but for the veto track

VtxValsTool Variables

In what follows below, whenever the first 2 vertices are referenced, they will be called "Vtx" and "Vtx2". (This is denoted by "Vtx[/2]Xxx".) This is to maintain backward compatibility with existing code. If there is no second vertex in the event, the Vtx2 quanitities are set to zero.

We've added some variables associated with a new kind of vertex: the "neutral" vertex. This vertex is made by combining the direction of a simple "charged" vertex with the direction of the line between the vertex point and the centroid of the CAL energy, weighted by the covariance matrices and by an empirical factor involving the energy, chi-squareds, opening angle, etc. In the table below, "VtxNeut" refers to the neutral vertex made from the first ("best") charged vertex, and "VtxNeut1" to a the neutral vertex made from the best track. (For 1-track vertices, these would be the same.)

("Vtx[/Neut/Neut1]XXX" means that there are 3 variables: VtxXxx, VtxNeutXxx, and VtxNeut1Xxx.)

Variable Type Description
VtxNumVertices INumber of vertices in the event
Vtx[/2/Neut/Neut1][X/Y/Z]Dir F[x/y/z] direction cosine of the vertex: the first is "Vtx"; the 2nd is "Vtx2". For Neut and Neut1, see above.
VtxPhi FAzimuthal angle of vertex, radians (direction of source, not flight direction!) Range: (0,2pi)
VtxTheta FPolar angle of vertex, radians (ditto direction)
VtxThetaErr FError on the measurement of theta
VtxPhiErr FError on the measurement of phi.
Vtx[/Neut/Neut1]S[XX/YY] F[x-x/y-y] element of the covariance matrix; square of error on [x/y]
Vtx[/Neut/Neut1]SXY Fx-y element of the covariance matrix; covariance
Vtx[/2][X/Y/Z]0 F[x/y/z] coordinate of vertex The first vertex is "Vtx"; the 2nd is "Vtx2". If the two tracks making up the vertex are nearly parallel, the coordinates of the vertex may become very large.
Vtx2TransDoca
Vtx[/2]Angle FAngle between the two tracks of the vertex (radians); the first vertex is "Vtx"; the 2nd is "Vtx2".
Vtx[/2]DOCA FDistance of closest approach between the two tracks; the first vertex is "Vtx"; the 2nd is "Vtx2".
Vtx[/2]HeadSep FDistance between the heads of the two tracks; the first vertex is "Vtx"; the 2nd is "Vtx2".
Vtx2LongDoca FLongitudinal distance of the 2nd vertex along the axis of the first vertex; positive if the 2nd vertex is below the first.
Vtx2TransDoca FTransverse distance of the 2nd vertex point from the axis of the first vertex
Vtx[/2]Status FSummary of track composition and topology. See TkrVertex.h in the Event package for the current description. The definitions as of GR v7r2 are:

    |  0   0   0   0  |  0   0   0   0  |  0   0   0   0  |  0   0   0   0   |
                                         [Track Topology ] [Track composition]

    ONETKRVTX = 0x0001,  //Set if single track vertex
    TWOTKRVTX = 0x0002,  //Set if 2 track vertex
    MULTKRVTX = 0x0004,  //Set if >2 track vertex
	NEUTRALVTX = 0x0008,  //Set if vertex includes neutral energy vector
    DOCAVTX   = 0x0010,  //Set if vertex location set by DOCA point
    FIRSTHIT  = 0x0020,  //Set if two tracks share first hit
    STAGVTX   = 0x0040,  //Set if tracks don't start in same plane (staggered)
    CROSSTKR  = 0x0080   //Set if DOCA location lies inside track hits

VtxQuality FVertex quality parameter used to order the possible vertices and select the best one. Should generally not be used in analysis.
VtxChisq FThe covariant chi-squared for the pairing of the tracks.
VtxS[1/2] FDistance of DOCA point from head of track [1/2]
VtxAddedRL FThe additional radiation lengths prior to the first measured silicon strip hit at the vertex location. New!


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