[Halld-offline] Gluex event sizes in pythia MC

[Richard Jones]

David,

Ok, I can certainly do that.  I will post the distribution of hits in each detector.  Converting those to event size will not be a trivial task because different detectors have different numbers of words per hit, eg. 4 in the Bcal or TOF (2 ends x adc+tdc) vs 2 for the CDC and most other detectors.

-Richard J.


On 10/28/2010 1:06 AM, David Lawrence wrote:
> Hi Richard,
>
>       I can certainly see the benefits of the clean separation that you
> have advocated for some time. I even tried my best to make the arguments
> on your behalf when the issue came up at offline meetings over the last
> year or so. The consensus, however, was to make the truth information
> associated with each hit a little more accessible hence the
> contamination of the hits tree in the data model.
>
>       Given the state of things as they are, I think the best estimates
> for event size from the hddm data would have to be derived by looking
> only at the number of hits in each detector. The raw data will likely
> have header words with the crate and slot number encoded followed by
> data words containing the digitized hit value in the lower bits and
> channel info in the upper bits. If it's easy to make plots of just the
> number of cathode hits and the number of anode hits, then we can
> calculate the bytes in the raw data file assuming two 4-byte words for
> each cathode hit (time and amplitude) and one 4-byte word for each anode
> hit (time only). Headers will have to be estimated in some way. Sascha
> has done this before and so may have some comment.
>
>       Note that I'm hoping to start looking at the details of the raw
> data format in a couple of weeks. We will need a hddm to raw-data-evio
> converter so we can test out the online systems prior to first beam.
> This will hopefully give us a very accurate idea of the data volumes we
> can expect as well.
>
> Regards,
> -David
>


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