Difference between revisions of "Constants to Review"

Revision as of 16:23, 2 June 2014

These are constants whose values need to be revisited

Digitization-level constants

CDC

a_scale = 1.0E6/1.3E5

FDC

a_scale = 2.4E4/1.3E5; // for cathodes, what about wires?

FCAL

a_scale = 4.0E1/2.5E5

BCAL

a_scale = 0.0001; // 100 keV/count (?)

TOF

a_scale = 0.2/5.2E5

ADC: hit->sigma_t = 4.0; // ns (what is the fADC time resolution?)
TDC: hit->sigma_t = 0.160; // ns (what is the TOF TDC time resolution?)
t0 offset for fADC?

Start Counter

a_scale = 2.0E-2/5.2E-5

ADC: hit->sigma_t = 4.0; // ns (what is the fADC time resolution?)
TDC: hit->sigma_t = 0.160; // ns (what is the TOF TDC time resolution?)
t0 offset for fADC?

Reconstruction constants

CDC/DCDCTrackHit_factory.h

w_eff=29.5e-9; gas_gain=1e5; hit->dist = hit->tdrift*55.0E-4; // Use number hardwired in simulation for now

ring/straw counting starts at 1

FDC

FDC/DFDCGeometry.h has a bunch of constants that need to be reconciled with HDGeant/hitFDC.c

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

FCAL

Various constants in DFCALCluster::shower_profile()

BCAL

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;

In DBCALPoint::DBCALPoint()
  estimates of m_sig_z

In DBCALShower_factory_IU::DBCALShower_factory_IU()
  energy calibration parameters

In DBCALUnifiedHit_factory::brun()
  loading timewalk parameters from CCDB
 

mcsmear

void SmearFCAL(s_HDDM_t *hddm_s):
    double t=fcaltruthhit->t + SampleGaussian(200.0E-3); // smear by 200 ps fixed for now 7/2/2009 DL