diff -u -r1.2 -r1.3
--- FADCEcalReadoutDriver.java	20 Mar 2013 01:03:32 -0000	1.2
+++ FADCEcalReadoutDriver.java	24 Oct 2013 20:01:54 -0000	1.3
@@ -22,15 +22,16 @@

 import org.lcsim.hps.recon.ecal.EcalConditions;
 import org.lcsim.hps.recon.ecal.HPSRawCalorimeterHit;
 import org.lcsim.hps.util.ClockSingleton;

+import org.lcsim.hps.util.RandomGaussian;

 import org.lcsim.hps.util.RingBuffer;
 import org.lcsim.util.lcio.LCIOConstants;
 
 /**

- * Performs readout of ECal hits.
- * Simulates time evolution of preamp output pulse.

+ * Performs readout of ECal hits. Simulates time evolution of preamp output
+ * pulse.

  *
  * @author Sho Uemura <[log in to unmask]>

- * @version $Id: FADCEcalReadoutDriver.java,v 1.2 2013/03/20 01:03:32 meeg Exp $

+ * @version $Id: FADCEcalReadoutDriver.java,v 1.3 2013/10/24 20:01:54 meeg Exp $

  */
 public class FADCEcalReadoutDriver extends EcalReadoutDriver<RawCalorimeterHit> {
 

@@ -82,6 +83,8 @@

     private double scaleFactor = 128;
     private double fixedGain = -1;
     private boolean constantTriggerWindow = false;

+    private boolean addNoise = false;
+    private double pePerMeV = 2.0; //photoelectrons per MeV, used to calculate noise

 
     public FADCEcalReadoutDriver() {
         flags = 0;

@@ -90,6 +93,10 @@

 //        converter = new HPSEcalConverter(null);
     }
 

+    public void setAddNoise(boolean addNoise) {
+        this.addNoise = addNoise;
+    }
+

     public void setConstantTriggerWindow(boolean constantTriggerWindow) {
         this.constantTriggerWindow = constantTriggerWindow;
     }

@@ -375,8 +382,14 @@

         //fill the readout buffers
         for (CalorimeterHit hit : hits) {
             RingBuffer eDepBuffer = eDepMap.get(hit.getCellID());

+            double energyAmplitude = hit.getRawEnergy();
+            if (addNoise) {
+                //add preamp noise and photoelectron Poisson noise in quadrature
+                double noise = Math.sqrt(Math.pow(EcalConditions.physicalToNoise(hit.getCellID()) * EcalConditions.physicalToGain(hit.getCellID()), 2) + hit.getRawEnergy() * ECalUtils.MeV / pePerMeV);
+                energyAmplitude += RandomGaussian.getGaussian(0, noise);
+            }

             for (int i = 0; i < bufferLength; i++) {

-                eDepBuffer.addToCell(i, hit.getRawEnergy() * pulseAmplitude((i + 1) * readoutPeriod + readoutTime() - (ClockSingleton.getTime() + hit.getTime())));

+                eDepBuffer.addToCell(i, energyAmplitude * pulseAmplitude((i + 1) * readoutPeriod + readoutTime() - (ClockSingleton.getTime() + hit.getTime())));

             }
         }
     }