code: def beam_kev(self,get_error=False):
          
          
          # get epics pointer
          epics = self.epics
          
          # fetch stds
          if get_error:
              attr = 'std'
          else:
              attr = 'mean'
          
          # get inital beam energy in keV
          beam = getattr(epics.target_bias,attr)/1000.
              
          # get RB cell voltage
          bias15 = getattr(epics.bias15,attr)/1000.
          
          # get platform bias 
          if self.area == 'BNMR':
              platform = getattr(epics.nmr_bias,attr)
          elif self.area == 'BNQR':
              platform = getattr(epics.nqr_bias,attr)/1000.
          else:
              raise RuntimeError('Area not recognized')
          
          if get_error:
              return np.sqrt(np.sum(np.square((beam,bias15,platform)))) # keV
          else:
              return beam-bias15-platform
docs: Get the beam energy in kev, based on typical biases: 
                  itw (or ite bias) - bias15 - platform bias
                  
              if get_error: fetch error in value, rather than value