Difference between revisions of "Constants to Review"

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(→‎BCAL)
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</pre>
 
</pre>
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 +
==Tables==
 +
 +
'''CCDB table - BCAL/bcal_parms'''
 +
{|class="wikitable"
 +
! Name
 +
! Value
 +
! Description
 +
! Action
 +
|-
 +
| style="width:70px;" | BCAL_DARKRATE_GHZ
 +
| style="width:50px;" | 0.0176
 +
| style="width:400px;" | Silicon PMT dark rate (from GlueX-doc-1754-v3)
 +
|
 +
|-
 +
| BCAL_SIGMA_SIG_RELATIVE
 +
| 0.105
 +
| Single PE width to amplitude ratio 6.489/61.67 = 0.105 (from GlueX-doc-1754-v3)
 +
|
 +
|-
 +
| BCAL_SIGMA_PED_RELATIVE
 +
| 0.139
 +
| Pedestal width to single PE amplitude ratio 8.585/61.67 = 0.139 (from GlueX-doc-1754-v3)
 +
|
 +
|-
 +
| BCAL_SIPM_GAIN_VARIATION
 +
| 0.04
 +
| Variation of gains between individual SiPM tiles. Yi measured a value of ~4% and indicated this in private communication.
 +
|
 +
|-
 +
| BCAL_XTALK_FRACT         
 +
| 0.10
 +
| This factor includes both the cross-talk and after-pulse probability for a 100ns window.
 +
|
 +
|-
 +
| BCAL_INTWINDOW_NS       
 +
| 100.
 +
| integration widnows in [ns]
 +
|
 +
|-
 +
| BCAL_DEVICEPDE           
 +
| 0.21
 +
| Photon detection efficiency (from GlueX-doc-1754-v3)
 +
|
 +
|-
 +
| BCAL_SAMPLING_FRACT     
 +
| 0.095
 +
| Sampling Fraction
 +
|
 +
|-
 +
| BCAL_AVG_DARK_DIGI_VALS_PER_EVENT
 +
| 240
 +
| Digitized values due to dark pulses only: Inner region has 3 digitized values/event, Outer region has 2 digitized values/event
 +
|
 +
|-
 +
| BCAL_PHOTONSPERSIDEPERMEV_INFIBER 
 +
| 75
 +
| try to extract from GlueX-doc-1069 back to photons per side per MeV in fiber
 +
|
 +
|-
 +
| BCAL_SAMPLINGCOEFA 
 +
| 0.042
 +
| Set the sampling smearing coefficients ( from GlueX-doc 827 v3 Figure 13 )
 +
|
 +
|-
 +
| BCAL_SAMPLINGCOEFB 
 +
| 0.013
 +
|
 +
|
 +
|-
 +
| BCAL_TIMEDIFFCOEFA
 +
| 0.098994949
 +
| time smearing comes from beam test time difference resolution with beam incident on the center of the module
 +
|
 +
|-
 +
| BCAL_TIMEDIFFCOEFB
 +
| 0
 +
| no floor term, but leave the option here
 +
|
 +
|- 
 +
| BCAL_THRESH_MEV
 +
| 1.
 +
| Threshold applied to energy deposition in MeV (HDGeant)
 +
|
 +
|-
 +
| BCAL_TWO_HIT_RESOL
 +
| 50.
 +
| time window for two hit resolution in ns
 +
|
 +
|-
 +
| BCAL_MAX_HITS  
 +
| 100
 +
| maximum number of hits per readout channels
 +
|
 +
|}
 +
 +
'''CCDB table - BCAL/mc_parms'''
 +
{|class="wikitable"
 +
! Name
 +
! Value
 +
! Description
 +
! Action
 +
|-
 +
| style="width:70px;" | ATTEN_LENGTH
 +
| style="width:50px;" | 300.
 +
| style="width:400px;" |
 +
|
 +
|-
 +
| C_EFFECTIVE
 +
| 16.75
 +
|
 +
|
 +
|-
 +
| SiPM_tbin_width
 +
| 0.100
 +
|
 +
|
 +
|}
 +
 +
 +
'''CCDB table - BCAL/cluster_merging'''
 +
{|class="wikitable"
 +
! Name
 +
! Value
 +
! Description
 +
! Action
 +
|-
 +
| style="width:70px;" | MIN_CLUSTER_SEPARATION_XY
 +
| style="width:50px;" | 15.0
 +
| style="width:450px;" | Minimum separation between 2 clusters for them NOT to be merged (cm)
 +
|
 +
|-
 +
| MIN_CLUSTER_SEPARATION_Z
 +
| 30.0
 +
|
 +
|
 +
|}
  
 
== TOF ==
 
== TOF ==

Revision as of 18:34, 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


CCDB table - FCAL/fcal_parms

Name Value Description Action
FCAL_PHOT_STAT_COEF 0.035 Photon-statistics factor for smearing hit energy
FCAL_BLOCK_THRESHOLD 0.02 Single block energy threshold (applied after smearing, units of GeV)
FCAL_ATTEN_LENGTH1 100. Attenuation length for Outer Glass (in cm)
FCAL_ATTEN_LENGTH2 73.1 Attenuation length for Inner Glass (in cm)
FCAL_RHG_RADIUS 30. Radius of inner lead glass blocks in cm
FCAL_C_EFFECTIVE 15. effective speed of light in glass in cm/ns
FCAL_WIDTH_OF_BLOCK 4. block width in cm
FCAL_LENGTH_OF_BLOCK 45. block length in cm
FCAL_TWO_HIT_RESOL 75. time window for two hit separation in ns
FCAL_MAX_HITS 100 maximum number of hits in a single block
FCAL_THRESH_MEV 5. threshold applied in a block (in hdgeant) Note: different unit than for smeared-blocks threshold (see above)
FCAL_ACTIVE_RADIUS 120. radius of the calorimeter
FCAL_CENTRAL_ROW 29 number of blocks in central row
FCAL_CENTRAL_COLUMN 29 number of blocks in central column

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;

Tables

CCDB table - BCAL/bcal_parms

Name Value Description Action
BCAL_DARKRATE_GHZ 0.0176 Silicon PMT dark rate (from GlueX-doc-1754-v3)
BCAL_SIGMA_SIG_RELATIVE 0.105 Single PE width to amplitude ratio 6.489/61.67 = 0.105 (from GlueX-doc-1754-v3)
BCAL_SIGMA_PED_RELATIVE 0.139 Pedestal width to single PE amplitude ratio 8.585/61.67 = 0.139 (from GlueX-doc-1754-v3)
BCAL_SIPM_GAIN_VARIATION 0.04 Variation of gains between individual SiPM tiles. Yi measured a value of ~4% and indicated this in private communication.
BCAL_XTALK_FRACT 0.10 This factor includes both the cross-talk and after-pulse probability for a 100ns window.
BCAL_INTWINDOW_NS 100. integration widnows in [ns]
BCAL_DEVICEPDE 0.21 Photon detection efficiency (from GlueX-doc-1754-v3)
BCAL_SAMPLING_FRACT 0.095 Sampling Fraction
BCAL_AVG_DARK_DIGI_VALS_PER_EVENT 240 Digitized values due to dark pulses only: Inner region has 3 digitized values/event, Outer region has 2 digitized values/event
BCAL_PHOTONSPERSIDEPERMEV_INFIBER 75 try to extract from GlueX-doc-1069 back to photons per side per MeV in fiber
BCAL_SAMPLINGCOEFA 0.042 Set the sampling smearing coefficients ( from GlueX-doc 827 v3 Figure 13 )
BCAL_SAMPLINGCOEFB 0.013
BCAL_TIMEDIFFCOEFA 0.098994949 time smearing comes from beam test time difference resolution with beam incident on the center of the module
BCAL_TIMEDIFFCOEFB 0 no floor term, but leave the option here
BCAL_THRESH_MEV 1. Threshold applied to energy deposition in MeV (HDGeant)
BCAL_TWO_HIT_RESOL 50. time window for two hit resolution in ns
BCAL_MAX_HITS 100 maximum number of hits per readout channels

CCDB table - BCAL/mc_parms

Name Value Description Action
ATTEN_LENGTH 300.
C_EFFECTIVE 16.75
SiPM_tbin_width 0.100


CCDB table - BCAL/cluster_merging

Name Value Description Action
MIN_CLUSTER_SEPARATION_XY 15.0 Minimum separation between 2 clusters for them NOT to be merged (cm)
MIN_CLUSTER_SEPARATION_Z 30.0

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 */
//------------------------------------------------
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