lcsim/src/org/lcsim/recon/tracking/digitization/sisim

diff -u -r1.1 -r1.2
--- CDFSiSensorSim.java	24 Apr 2009 01:22:58 -0000	1.1
+++ CDFSiSensorSim.java	13 May 2009 15:15:50 -0000	1.2
@@ -196,7 +196,7 @@

             // Set up segments
             double segment_length = track.getLength()/nsegments;
             double segment_charge = track.getEloss()/nsegments/_sensor.getBulk().ENERGY_EHPAIR;

-            

+

 //            System.out.println("length of subsegments: " + segment_length);
 //            System.out.println("subsegment charge: " + segment_charge);
             

@@ -408,22 +408,33 @@

         
 //        System.out.println("Position: "+local_position);
         

-        double carrier_mobility = _sensor.getBulk().mobility(carrier);

 //        System.out.println("Carrier: "+carrier);

-        

+
+        //  Get the magnetic field - already in Si units (Tesla)

         Hep3Vector b_field = _sensor.getBField(local_position);
 //        System.out.println("B field: "+b_field);

-        
-        Hep3Vector e_field = _sensor.electricField(local_position);

+
+        //  Get the electric field and convert from V/mm to Si units (V/m)
+        Hep3Vector e_field = VecOp.mult(1000., _sensor.electricField(local_position));

 //        System.out.println("E field: "+e_field);

-        
-        double tan_lorentz = _sensor.getBulk().tanLorentzAngle(b_field.magnitude(), carrier);
-        
-//        System.out.println("Tan lorentz: "+tan_lorentz);
-        
-        Hep3Vector drift_direction = VecOp.mult(carrier.charge(),VecOp.unit(VecOp.add(
-                e_field,VecOp.mult(tan_lorentz, VecOp.cross(e_field,VecOp.unit(b_field)))
-                )));

+
+        //  Get the mobility and convert from cm^2/V/s to Si units of m^2/V/s
+        double mobility = 1.0e-4 * _sensor.getBulk().mobility(carrier);
+
+        //  Get the charge (to be consistent with mobility, this should be in units of e)
+        double qmu =  carrier.charge() * mobility;
+//        System.out.println("mobility: "+mobility+" charge: "+qmu/mobility;
+        
+        //  Calculate the velocity parallel to the E field vpar = q * mu * E
+        Hep3Vector vpar = VecOp.mult(qmu, e_field);
+//        System.out.println("vpar: "+vpar);
+
+        //  Calculate the velocity perpendicular to the E field vperp = q^2 * mu^2 * E x B
+        Hep3Vector vperp = VecOp.mult(qmu*qmu, VecOp.cross(e_field, b_field));
+//        System.out.println("vperp: "+vperp);
+
+        //  Calculate a unit vector in the drift direction
+        Hep3Vector drift_direction = VecOp.unit(VecOp.add(vpar, vperp));

         
 //        System.out.println("Drift direction: "+drift_direction);
         

lcsim/src/org/lcsim/recon/tracking/digitization/sisim

diff -u -r1.3 -r1.4
--- GenericReadoutChip.java	7 May 2009 22:36:21 -0000	1.3
+++ GenericReadoutChip.java	13 May 2009 15:15:51 -0000	1.4
@@ -126,7 +126,7 @@

 
         //  return the digitized charge data as a map that associates a hit
         //  channel with a list of raw data for the channel

-        return digitize(data);

+        return digitize(data, electrodes);

     }
 
     /**

@@ -168,7 +168,8 @@

      * @param data electrode data collection
      * @return map associating channels with a list of raw data
      */

-    private SortedMap<Integer, List<Integer>> digitize(SiElectrodeDataCollection data) {

+    private SortedMap<Integer, List<Integer>> digitize(SiElectrodeDataCollection data,
+            SiSensorElectrodes electrodes) {

 
         //  Create the map that associates a given sensor channel with it's list of raw data
         SortedMap<Integer, List<Integer>> chip_data = new TreeMap<Integer, List<Integer>>();

@@ -179,8 +180,36 @@

             //  Fetch the electrode data for this channel
             SiElectrodeData eldata = data.get(channel);
 

+            //  Get the charge in units of electrons
+            double charge = eldata.getCharge();
+
+            //  If the charge is below the neighbor threshold, don't digitize it
+            if (charge < _neighbor_threshold) continue;
+
+            //  If charge is between neighbor and noise thresholds, check it's neighbors
+            if (charge < _noise_threshold) {
+
+                //  Loop over neighbors and look for a neighbor with charge above the noise
+                boolean nbrhit = false;
+                for (Integer nbr : electrodes.getNearestNeighborCells(channel)) {
+
+                    //  See if we have electrode data for this neighbor
+                    SiElectrodeData nbrdata = data.get(nbr);
+                    if (nbrdata == null) continue;
+
+                    //  See if we have found a neigbor above the noise threshold
+                    if (nbrdata.getCharge() >= _noise_threshold) {
+                        nbrhit = true;
+                        break;
+                    }
+                }
+                
+                //  If there were no neighbor channels above threshold, don't digitize it
+                if (!nbrhit) continue;
+            }
+

             //  Calculate the ADC value for this channel and make sure it is positive

-            int adc = getChannel(channel).computeAdcValue(eldata);

+            int adc = getChannel(channel).computeAdcValue(charge);

             if (adc <= 0) {
                 continue;
             }

@@ -394,10 +423,7 @@

          * @param data electrode data
          * @return charge
          */

-        private int computeAdcValue(SiElectrodeData data) {
-
-            //  Get the charge in units of electrons
-            double charge = data.getCharge();

+        private int computeAdcValue(double charge) {

 
             //  Convert from electrons to ADC counts (1 electron = 1.6 x 10^-4 fC)
             int adc = (int) Math.floor(charge * 1.6e-4 * _adc_per_fC);