Difference between revisions of "Constants to Review"

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(CDC)
(FDC)
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'''CCDB table - FDC/fdc_parms'''
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{|class="wikitable"
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! Name
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! Value
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! Description
 +
! Action
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|-
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| style="width:70px;" | FDC_DRIFT_SPEED
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| style="width:50px;" | 0.0055
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| style="width:400px;" | electron drift velocity
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|
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|-
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| FDC_WIRE_DEAD_ZONE_RADIUS
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| 3.5
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| dead wire radius
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|
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|-
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| FDC_STRIP_DEAD_ZONE_RADIUS
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| 5.0
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| other dead wire radius
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|
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|-
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| FDC_ACTIVE_AREA_OUTER_RADIUS
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| 48.5
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|
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|
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|-
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| FDC_ANODE_CATHODE_SPACING
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| 0.5
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|
 +
|
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|-
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| FDC_TWO_HIT_RESOL
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| 25.
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|
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|
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|-
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| FDC_WIRES_PER_PLANE
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| 96
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|
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|
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|-
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| FDC_WIRE_SPACING
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| 1.
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|
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|
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|-
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| FDC_STRIPS_PER_PLANE
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| 192
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|
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|
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|-
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| FDC_STRIP_SPACING
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| 0.5
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|
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|
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|-
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| FDC_STRIP_GAP
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| 0.1
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|
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|
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|-
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| FDC_MAX_HITS
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| 100
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|
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|
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|-
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| FDC_K2
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| 1.15
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|
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|
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|-
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| FDC_STRIP_NODES
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| 3
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|
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|
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|-
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| FDC_THRESH_KEV
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| 1.
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|threshold in keV
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|
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|-
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| FDC_THRESH_STRIPS
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| 5.
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| threshold in pC
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|
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|-
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| FDC_ELECTRON_CHARGE
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| 1.6022e-4
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| electron charge in fC
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|
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|-
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| FDC_DIFFUSION_COEFF 
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| 1.1e-6
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| diffusion speed cm^2/s --> 200 microns at 1 cm
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|
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|-
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| FDC_TDRIFT_SIGMA
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| 3.6363636e-9
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| The error on the drift time in the FDC, used to gaussianly smear incoming hits
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|
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|-
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| FDC_CATHODE_SIGMA
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| 150.0
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| The error in the distance along the wire as measured by the cathodes (NOT including Lorentz effect, but including fluctuations due to ion trail density, in microns)
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|
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|-
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| FDC_PED_NOISE
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| 0.0
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| The FDC pedestal noise is used to smear the cathode ADC values such that the position along the wire has the resolution specified by FDC_CATHODE_SIGMA, units in pC (calculated from FDC_CATHODE_SIGMA in SmearFDC)
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|
 +
|-
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| FDC_TIME_WINDOW
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| 1000.0E-9
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| Time window for acceptance of FDC hits units in seconds
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|
 +
|-
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| FDC_HIT_DROP_FRACTION 
 +
| 0.0
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| Fraction of FDC hits to randomly drop (0=drop nothing 1=drop everything)
 +
|
 +
|}
  
 
== FCAL ==
 
== FCAL ==

Revision as of 18:26, 3 June 2014

These are constants whose values need to be revisited


CDC

Description Variable Value File Line Action to take
fADC counts -> physical units a_scale 1.0E6/1.3E5 DCDCHit_factory.cc
Energy conversion factor for dE calc. w_eff 29.5E-9 DCDCTrackHit_factory.cc 109
Gain factor for dE calc. gas_gain 1.0E5 DCDCTrackHit_factory.cc 110
initial time -> drift conversion 55.0E-4 DCDCTrackHit_factory.cc 113 Remove


CCDB table - CDC/cdc_parms

Name Value Description Action
CDC_TDRIFT_SIGMA 2.8181818181818e-9 The error on the drift time in the CDC, used to gaussianly smear actual CDC hits.
CDC_TIME_WINDOW 1000.0E-9 The time window for which CDC hits are accumulated (in sec), used for background determination
CDC_PEDESTAL_SIGMA 0.00000006 The error in the energy deposition measurement in the CDC due to pedestal noise
CDC_DRIFT_SPEED 0.0055 CDC drift speed (unit?)
CDC_TWO_HIT_RESOL 25. time window for two hit resolution (in ns)
CDC_MAX_HITS 100 number of hit per readout channel
CDC_THRESH_KEV 1. threshold applied (in KeV)
CDC_STRAW_RADIUS 0.8 straw radius (in cm)

FDC

Description Variable Value File Line
fADC counts -> physical units a_scale 2.4E4/1.3E5 DFDCHit_factory.cc
Time range used to cluster cathode hits (ns) TIME_SLICE 10 DFDCCathodeCluster_factory.cc 10
Energy conversion factor for dE calc. W_EFF 30.2e-9 DFDCPseudo_factory.cc 26
Gain factor for dE calc. GAS_GAIN 8e4 DFDCPseudo_factory.cc 27


CCDB table - FDC/fdc_parms

Name Value Description Action
FDC_DRIFT_SPEED 0.0055 electron drift velocity
FDC_WIRE_DEAD_ZONE_RADIUS 3.5 dead wire radius
FDC_STRIP_DEAD_ZONE_RADIUS 5.0 other dead wire radius
FDC_ACTIVE_AREA_OUTER_RADIUS 48.5
FDC_ANODE_CATHODE_SPACING 0.5
FDC_TWO_HIT_RESOL 25.
FDC_WIRES_PER_PLANE 96
FDC_WIRE_SPACING 1.
FDC_STRIPS_PER_PLANE 192
FDC_STRIP_SPACING 0.5
FDC_STRIP_GAP 0.1
FDC_MAX_HITS 100
FDC_K2 1.15
FDC_STRIP_NODES 3
FDC_THRESH_KEV 1. threshold in keV
FDC_THRESH_STRIPS 5. threshold in pC
FDC_ELECTRON_CHARGE 1.6022e-4 electron charge in fC
FDC_DIFFUSION_COEFF 1.1e-6 diffusion speed cm^2/s --> 200 microns at 1 cm
FDC_TDRIFT_SIGMA 3.6363636e-9 The error on the drift time in the FDC, used to gaussianly smear incoming hits
FDC_CATHODE_SIGMA 150.0 The error in the distance along the wire as measured by the cathodes (NOT including Lorentz effect, but including fluctuations due to ion trail density, in microns)
FDC_PED_NOISE 0.0 The FDC pedestal noise is used to smear the cathode ADC values such that the position along the wire has the resolution specified by FDC_CATHODE_SIGMA, units in pC (calculated from FDC_CATHODE_SIGMA in SmearFDC)
FDC_TIME_WINDOW 1000.0E-9 Time window for acceptance of FDC hits units in seconds
FDC_HIT_DROP_FRACTION 0.0 Fraction of FDC hits to randomly drop (0=drop nothing 1=drop everything)

FCAL

Description Variable Value File Line/Function
fADC counts -> physical units a_scale 1.0E6/1.3E5 DFCALHit_factory.cc 53
shower profile parameters? DFCALCluster shower_profile()
mcsmear gaussian time resolution (ps) 200. mcsmear/smear.cc 869


BCAL

Description Variable Value File Line
fADC counts -> physical units, 100 keV/count (?) a_scale 0.0001 DBCALHit_factory.cc 38
non-linear shower energy corrections DBCALShower_factory_IU.cc 23-46
sigma(z) estimation, cm (with TDC info, from NIM article) m_sig_z 1.1 / sqrt(E) DBCALPoint.cc 96
sigma(z) estimation, cm (without TDC info, from NIM article) m_sig_z 30. DBCALPoint.cc 104

In DBCALUnifiedHit_factory::brun():34-119 - Need to revisit timewalk corrections.

Various clusterizing parameters/calculations:

DBCALCluster.cc:

  // The method below for determining sig_theta works better than the one
  // above. sigma_z is determined using errors when reconstructing MC data.
  double sigma_z = sqrt(1.394*1.394/m_E + 0.859*0.859);
  m_sig_theta = sigma_z*sin(m_theta)*sin(m_theta)/DBCALGeometry::BCALINNERRAD;

DBCALCluster_factory.cc:

  In DBCALCluster_factory::evnt(), energy threshold is 5*k_MeV

  In DBCALCluster_factory::clusterize()
    float seedThresh = 1*k_GeV;
    float minSeed = 10*k_MeV;

  In DBCALCluster_factory::overlap( const DBCALCluster& highEClust,
                                    const DBCALCluster& lowEClust )
  //deltaPhi_force_merge and delta_z_force_merge were determined by looking
  //at the separation of decay photons from pi0's from a pythia sample.
  //There are no events where the decay photons have separation
  //(delta_phi < 0.2 && delta_z < 25 cm), so in most cases it should be safe
  //to merge clusters together if they are so close.
  const double deltaPhi_force_merge = 0.1; //radians
  const double delta_z_force_merge = 15.0*k_cm;

  //A major cause of extra clusters are lower energy hits, which have poor
  //z-resolution and so are not properly merged. Treat low energy
  //clusters (< 40 MeV) as a special case. Again, hopefully this is only
  //a temporary fix until we have a more comprehensive solution.
  const double delta_z_force_merge_low_E = 40.0*k_cm;
  const double low_E = .04*k_GeV;

TOF

Description Variable Value File Line
fADC counts -> physical units a_scale 0.2/5.2E5 DTOFHit_factory.cc
fADC time resolution (ns) hit->sigma_t 4.0 DTOFHit_factory.cc
TDC time resolution (ns) hit->sigma_t 0.160 DTOFHit_factory.cc

t0 offset for fADC?

Start Counter

Description Variable Value File Line
fADC counts -> physical units a_scale 2.0E-2/5.2E-5 DSCHit_factory.cc 36
fADC time resolution (ns) hit->sigma_t 4.0 DSCHit_factory.cc 37
TDC time resolution (ns) hit->sigma_t 0.160 DSCHit_factory.cc 38

Geometry constants

FDC

FDC/DFDCGeometry.h has a bunch of constants that need to be reconciled with HDGeant/hitFDC.c Note that HDGeant/hitFDC.c actually reads these out of the CCDB (!)

//----- These were cut from HDGeant/hitFDC.c -----
#define DRIFT_SPEED           .0055
#define CATHODE_ROT_ANGLE     1.309  // 75 degrees
//#define CATHODE_ROT_ANGLE     0.7854 // 45 degrees
#define WIRE_DEAD_ZONE_RADIUS 3.2
#define ANODE_CATHODE_SPACING 0.5
#define TWO_HIT_RESOL         250.
#define WIRES_PER_PLANE       96
#define WIRE_SPACING          1.0
#define U_OF_WIRE_ZERO        (-((WIRES_PER_PLANE-1)*WIRE_SPACING)/2)
#define STRIPS_PER_PLANE      192 
#define STRIP_SPACING         0.5
#define U_OF_STRIP_ZERO            (-((STRIPS_PER_PLANE-1)*STRIP_SPACING)/2)
#define STRIP_GAP             0.1
#define MAX_HITS             100
//#define K2                  1.15
#define STRIP_NODES           3
#define THRESH_KEV           1.
#define THRESH_STRIPS        5.   /* mV */
#define ELECTRON_CHARGE 1.6022e-4 /* fC */
//------------------------------------------------