code: def calcTransM(self, gamma=None):
          
          sconf = self.getConfig(type='simu')
          if 'l' in sconf:
              l = float(sconf['l'])
          else:
              l = 0
          self.transM = mathutils.transDrift(l, gamma)
          self.transM_flag = True
          return self.transM
docs: calculate transport matrix
  
          :param gamma: electron energy measured by mc^2
          :return: transport matrix
          :rtype: numpy array