Updating how time offsets are applied, dealing with different start times (#1074)

Author: N-Plx

reconstruction/alert/src/main/java/org/jlab/rec/atof/hit/ATOFHit.java

@@ -21,12 +21,11 @@ public class ATOFHit {
 
     private int sector, layer, component, order;
     private int tdc, tot;
-    private float startTime;
+    private Float startTime;
     private double time, energy, x, y, z;
     private String type;
     private boolean isInACluster;
     private int associatedClusterIndex;
-    private double meanTimeAligned;
     int idTDC;
 
 
@@ -82,13 +81,9 @@ public double getTime() {
         return time;
     }
 
-    public double getStartTime() {
+    public Float getStartTime() {
         return this.startTime;
     }
-    
-    public double getMeanTimeAligned(){
-        return this.meanTimeAligned;
-    }
 
     public void setTime(double time) {
         this.time = time;
@@ -195,27 +190,18 @@ public final String makeType() {
      * unsupported.
      */
     public final int convertTdcToTime() {
-        
         //Converting tdc to ns, event start time correction
-        this.time = Parameters.TDC2TIME*this.tdc - this.startTime;
+        this.time = Parameters.TDC2TIME*this.tdc;
+        //If the startTime has been defined, remove it
+        if(this.startTime!= null) this.time -= this.startTime;
 
         //TODO: When table structure evolves, pay attention to order.
         //Key for the current channel 
         int key = this.sector*10000 + this.layer*1000 + this.component*10 + 0;//this.order;
-        //Key for the reference channel over which all the others sharing the same z are aligned 
-        int referenceModuleKey = this.component*10; 
 
         //Time offsets
         double[] timeOffsets = CalibrationConstantsLoader.ATOF_TIME_OFFSETS.get(key);
-        double[] timeOffsetsRef = CalibrationConstantsLoader.ATOF_TIME_OFFSETS.get(referenceModuleKey);
-        this.meanTimeAligned = timeOffsetsRef[0];
-        //The names below correspond to the CCDB entries
-        //They will most probably evolve
-        //For now let's say t0 is used to store the bar-to-bar and wedge-to-wedge alignments
         double t0 = timeOffsets[0];
-        double tChannelToChannelPhiAlignment = (t0 - this.meanTimeAligned);
-        if(this.type=="bar up" || this.type=="bar down") //bar alignment is done with the sum of the two times
-            tChannelToChannelPhiAlignment=tChannelToChannelPhiAlignment/2.;
 
         //tud is used to store the bar up - bar down alignment
         double tud = timeOffsets[1];
@@ -237,8 +223,6 @@ public final int convertTdcToTime() {
         double dtw3 = timeWalks[7];
         double chi2ndf = timeWalks[8];*/
 
-        //Veff corrections TO BE IMPLEMENTED
-        
         double veff, distance_to_sipm, timeOffset;
         if (null == this.type) {
             LOGGER.finest("Null hit type, cannot convert tdc to time.");
@@ -249,19 +233,20 @@ public final int convertTdcToTime() {
                     veff = Parameters.VEFF;
                     //Wedge hits are placed at the center of wedges and sipm at their top
                     distance_to_sipm = Parameters.WEDGE_THICKNESS / 2.;
-                    timeOffset = - tChannelToChannelPhiAlignment;
+                    timeOffset = - t0;
                 }
                 case "bar up" -> {
                     veff = Parameters.VEFF;
                     //The distance will be computed at barhit level when z information is available
                     distance_to_sipm = 0;
-                    timeOffset = - tud/2. - tChannelToChannelPhiAlignment;
+                    //t0 for bars is the sum of up+down channels->need 1/2
+                    timeOffset = - tud/2. - t0/2;
                 }
                 case "bar down" -> {
                     veff = Parameters.VEFF;
                     //The distance will be computed at barhit level when z information is available
                     distance_to_sipm = 0;
-                    timeOffset = + tud/2. - tChannelToChannelPhiAlignment;
+                    timeOffset = + tud/2. - t0/2;
                 }
                 case "bar" -> {
                     LOGGER.finest("Bar hit type, cannot convert tdc to time.");
@@ -418,7 +403,7 @@ public double getPhi() {
      * @param atof Detector object representing the atof, used to calculate
      * spatial coordinates.
      */
-    public ATOFHit(int sector, int layer, int component, int order, int tdc, int tot, float startTime, Detector atof) {
+    public ATOFHit(int sector, int layer, int component, int order, int tdc, int tot, Float startTime, Detector atof) {
         this.sector = sector;
         this.layer = layer;
         this.component = component;

reconstruction/alert/src/main/java/org/jlab/rec/atof/hit/BarHit.java

@@ -1,5 +1,7 @@
 package org.jlab.rec.atof.hit;
 
+import org.jlab.io.base.DataEvent;
+import org.jlab.io.hipo.HipoDataSource;
 import org.jlab.rec.atof.constants.Parameters;
 import org.jlab.rec.alert.constants.CalibrationConstantsLoader;
 
@@ -30,15 +32,19 @@ public ATOFHit getHitUp() {
      * 
      */
     public boolean isInTime() {
+        //Undefined start time is when useStartTime option is false in the yaml
+        //for example for usage with simulations
+        //-> we keep all the hits
+        if(this.hitUp.getStartTime() == null) return true;
         double timeShift = 0;
+        //TO DO: make this more robust
         //For FT electron for which the startTime is set at -1000
         //We need to shift where the cut is applied
+        //2180 = 2*1090 = 1000+90 for FD start time around 90ns
+        //if the data start time is not around 90, this will be a problem
         if(this.hitUp.getStartTime()<0) timeShift = 2180;
-        if(Math.abs(
-                this.hitUp.getTime()+this.hitDown.getTime()
-                        -timeShift
-                        -this.hitUp.getMeanTimeAligned())
-                <40)
+        if(Math.abs(this.hitUp.getTime()+this.hitDown.getTime()
+                        -timeShift)<40)
             return true;
         return false;
     }
@@ -70,17 +76,19 @@ public final void computeZ() {
      * 
      */
     public final void computeTime() {
-        //We pick the most energetic signal as the timing signal
-        double time_at_sipm, distance_to_sipm;
-        if(this.hitDown.getEnergy() > this.hitUp.getEnergy()) {
-            time_at_sipm = this.hitDown.getTime();
-            distance_to_sipm = Parameters.LENGTH_ATOF/2. - this.getZ();
-        }
-        else {
-            time_at_sipm = this.hitUp.getTime();
-            distance_to_sipm = Parameters.LENGTH_ATOF/2. + this.getZ();
-        }
-        this.setTime(time_at_sipm - distance_to_sipm/this.vEff);
+    //Select the most energetic hit as the timing reference
+    final boolean useDownstream = hitDown.getEnergy() > hitUp.getEnergy();
+    final double sipmTime   = useDownstream ? hitDown.getTime() : hitUp.getTime();
+    //veff correction
+    //t0 has already been removed.
+    //distance to SiPM is L/2+-z, part of it is absorbed into the t0 as:
+    //t0 = 2*offset+L/veff
+    //t_hit = t_u/d - 2*offset/2 -/+ tud/2 - 1/veff(L/2 -/+ z)
+    //t_hit = t_u/d - (t0)/2 -/+ tud/2 +/- z/veff
+    //Only the z part remains
+    final double zDirection = useDownstream ? +this.getZ() : -this.getZ();
+    final double correctedTime = sipmTime + zDirection / vEff;
+    this.setTime(correctedTime);
     }
 
     /**

reconstruction/alert/src/main/java/org/jlab/rec/atof/hit/HitFinder.java

@@ -5,7 +5,6 @@
 import org.jlab.geom.base.Detector;
 import org.jlab.io.base.DataBank;
 import org.jlab.io.base.DataEvent;
-import org.jlab.rec.alert.constants.CalibrationConstantsLoader;
 
 /**
  * The {@code HitFinder} class finds hits in the atof.
@@ -64,7 +63,7 @@ public void setWedgeHits(ArrayList<ATOFHit> wedge_hits) {
      * @param atof the {@link Detector} representing the atof geometry to match
      * the sector/layer/component to x/y/z.
      */
-    public void findHits(DataEvent event, Detector atof, float startTime) {
+    public void findHits(DataEvent event, Detector atof, Float startTime) {
         //For each event a list of bar hits and a list of wedge hits are filled
         this.barHits.clear();
         this.wedgeHits.clear();

reconstruction/alert/src/main/java/org/jlab/service/alert/ALERTEngine.java

@@ -175,7 +175,7 @@ public boolean processDataEvent(DataEvent event) {
                 int layer_pred = (int) pred[1];
                 int wedge_pred = (int) pred[2];
 
-                ATOFHit hit_pred = new ATOFHit(sector_pred, layer_pred, wedge_pred, 0, 0, 0, 0, ATOF);
+                ATOFHit hit_pred = new ATOFHit(sector_pred, layer_pred, wedge_pred, 0, 0, 0, 0f, ATOF);
                 double pred_x = hit_pred.getX();
                 double pred_y = hit_pred.getY();
                 double pred_z = hit_pred.getZ();
@@ -193,7 +193,7 @@ public boolean processDataEvent(DataEvent event) {
                     int sector = bank.getInt("sector", k);
                     int layer = bank.getInt("layer", k);
 
-                    ATOFHit hit = new ATOFHit(sector, layer, component, 0, 0, 0, 0, ATOF);
+                    ATOFHit hit = new ATOFHit(sector, layer, component, 0, 0, 0, 0f, ATOF);
 
                     double dx = pred_x - hit.getX();
                     double dy = pred_y - hit.getY();
@@ -212,9 +212,6 @@ public boolean processDataEvent(DataEvent event) {
             } catch (Exception ex) {
                 System.out.println("Exception in ALERTEngine processDataEvent: " + ex); // TODO: proper logging
             }
-
-
-            
         }
         return true;
     }

reconstruction/alert/src/main/java/org/jlab/service/atof/ATOFEngine.java

@@ -60,7 +60,7 @@ public boolean processDataEvent(DataEvent event) {
         if (!event.hasBank("RUN::config")) {
             return true;
         }
-        float startTime = 0;
+        Float startTime = null;
         if(useStartTime)
         {
             //This assumes the FD reconstruction produced an event with good startTime
@@ -101,14 +101,11 @@ public boolean processDataEvent(DataEvent event) {
         //projector.projectTracks(event);
         //rbc.appendMatchBanks(event, projector.getProjections());
 
-        // Why do we have to "find" hits? 
         //Hit finder init
         HitFinder hitfinder = new HitFinder();
         hitfinder.findHits(event, ATOF, startTime);
-
         ArrayList<ATOFHit> WedgeHits = hitfinder.getWedgeHits();
         ArrayList<BarHit> BarHits = hitfinder.getBarHits();
-        
         //Exit if hit lists are empty
         if (WedgeHits.isEmpty() && BarHits.isEmpty()) {
             //			System.out.println("No hits : ");