lcsim/sandbox/Partridge

diff -N MultipleScatter.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ MultipleScatter.java	29 Nov 2007 19:42:16 -0000	1.1
@@ -0,0 +1,50 @@

+/*
+ * MultipleScatter.java
+ *
+ * Created on November 21, 2007, 1:12 PM
+ *
+ */
+
+package org.lcsim.fit.helicaltrack;
+
+/**
+ * Encapsulate multiple scattering errors for a hit.
+ * HelicalTrackFitter does a straight-line fit of z(s).
+ * This is a good choice for barrel detectors that
+ * measure z.  For disk detectors, the z
+ * position is fixed and the measurement coordinate
+ * is r (which is the same as s in the high pT limit).
+ * In this case, taking dz as dr * z / r is suggested.
+ * @author Richard Partridge
+ * @version 1.0
+ */
+public class MultipleScatter {
+    private double _drphi;
+    private double _dz;
+    
+    /**
+     * Creates a new instance of MultipleScatter
+     * @param drphi Multiple scattering error in the r-phi plane
+     * @param dz Multiple scattering error in z assuming fixed s
+     */
+    public MultipleScatter(double drphi, double dz) {
+        _drphi = drphi;
+        _dz = dz;
+    }
+    
+    /**
+     * Return the multiple scattering error in the r-phi plane
+     * @return r-phi multiple scattering error (units are mm)
+     */
+    public double drphi() {
+        return _drphi;
+    }
+    
+    /**
+     * Return the multiple scattering error in z
+     * @return z coordinate multiple scattering error (units are mm)
+     */
+    public double dz() {
+        return _dz;
+    }
+}