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Hi,

I'm trying to process some of the cosmic run data in LCSim, by converting to LCIO and applying the existing ADC to energy algorithm to the data.  I have gotten to the point, after fixing various things, that I can get an energy estimation for each crystal from LCSim now.

I generated some plots from the hps_002891.evio.0 cosmic run file, which include one plot per crystal for ADC values, pedestal subtracted ADC sums, and energy in GeV.  The energy calculation was done with the EcalRawConverterDriver in LCSim which is the standard processor we use to convert from ADC to energy.

The file is here:

http://www.slac.stanford.edu/~jeremym/hps/EcalChannelPlots.root

You can open it with the ROOT TBrowser to look at the histograms.  The numbers in the histogram titles are the crate, slot, and channel identifying each crystal.

The ADC values and the pedestal subtracted sums look reasonable enough.

The energy values for each channel have a strange distribution, but I think that's what we expect right now as the LCSim code is not correctly converting the ADC counts to energy.

You can generate these plots yourself by running the following EVIO to LCIO converter job:

java -cp ./distribution/target/hps-distribution-3.1-SNAPSHOT-bin.jar org.hps.evio.EvioToLcio -b -R 2000 -x ./steering-files/src/main/resources/org/hps/steering/monitoring/EcalChannelPlots.lcsim hps_002891.evio.0

To run this successfully, you will first need to 'svn up' the trunk and rebuild, as I had to fix a number of minor issues today in the EvioToLcio class and related code.  (See SVN checkin messages for details.)

I think we should work on improving this code in LCSim so that the energy estimation is more reasonable.

Can we discuss whether EcalRawConverter and the EcalRawConverterDriver can be used for this calculation, possibly with some small modifications or additional configuration options?  Or do we need a new Driver entirely with a different energy calculation?

I know we will need accurate gain values by channel.  The "1.0" value used right now for all channels is off by approximately a factor of 4 from what you told me, so I can update this value in the conditions system to the suggested value of 0.227 until per channel gain values are available and loaded into the conditions database.

Let me know if you have any questions/comments about this.

--Jeremy

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