Constants to Review

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;

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	48
fADC time resolution (ns)	hit->sigma_t	4.0	DTOFHit_factory.cc	49
TDC time resolution (ns)	hit->sigma_t	0.160	DTOFHit_factory.cc	50

CCDB table - TOF/tof_parms

Name	Value	Description	Action
TOF_C_EFFECTIVE	15.0	effective light speed in the plastic scintillator paddles units [ns]
TOF_ATTEN_LENGTH	150.	attenuation legth of paddle units [cm]
TOF_POS_RES	3.0	TOF position resolution in the transvers direction of the paddle [cm]
TOF_ADC_TO_E	1.0	conversion of ADC to energy
TOF_TDC_MC_RES	0.06	TDC resolution as in the MC units [ns]
TOF_PHOTONS_PERMEV	8000.	scintillation photon generated per MeV energy
TOF_THETA_MAX	50.74	total internal reflection
TOF_PMT_SURFACE	19.63	PMT surface in cm^2
TOF_ADC_RES_MC	50.	adc resolution pC/count in MC
TOF_TDC_RES_MC	0.06	TDC resolution in ns
TOF_PMT_GAIN_MC	40000000.	PMT gain factor in MC
TOF_PHE_EFF	0.2	PMT quantum efficiency
TOF_REFLECT_EFF	0.5	reflection efficiency of scintillation light
TOF_CENT_TRES	-0.698970004	timing resolution in the center of the paddle log10(0.2ns)
TOF_ADC_TO_E	1.0	ADC to energy conversion factor in MC
TOF_HALFPADDLE	126.	half the length of a TOF paddle in cm
TOF_PADDLE_LENGTH	252.	half the length of a TOF paddle in cm
TOF_PADDLEWIDTH	6.	with of a TOF paddle in cm
TOF_E_THRESHOLD	0.001	Energy threshold in GeV
TOF_SIGMA	0.1	Timing resolution in [ns]
TOF_TWO_HIT_RESOL	25.	two hit resolution in tof [ns]
TOF_THRESH_MEV	0.	threshold applied to deposited energy in MC
TOF_MAX_HITS	25	maximum merged hits per paddle
TOF_MAX_PAD_HITS	25	maximum total hits per paddle

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

CCDB table - START_COUNTER/start_parms

Name	Value	Description	Action
START_SIGMA	0.3	Start counter timing resolution 300ps
START_PHOTONS_PERMEV	200.	Start counter number of photons per MeV
START_ATTEN_LENGTH	150.	attenuation length in cm
START_C_EFFECTIVE	15.	effective speed of light in cm/ns
START_TWO_HIT_RESOL	25.	time window for two hit resolution in ns
START_MAX_HITS	100	maximum number of hits per readout channel
START_THRESH_MEV	0.150	threshold in MeV
START_LIGHT_GUIDE	140.	light guid length in cm
START_ANGLE_COR	1.17	?
START_BENT_REGION	50.	?

Geometry constants

THESE ARE BEING UPDATED

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