[ROOT] TNtuple

From: Christian D. HAEBERLI (christian.haeberli@cern.ch)
Date: Thu May 11 2000 - 22:53:08 MEST


Dear Rooters

You helped me already a lot of times and I need your help once more.
Thank you in advance.

This week I made some test measurements in T9 at CERN. I read out 50 ADC
channels and  2 wired chambers (4 plains). I made runs of about 20'000
evemts. 

Now I have to following data structure in binary files:
data is structured in spills of about 400 events. First there all ADC
values of one spill, last second are the values (coordinates)of the
wired chambers of one spill.

Now, I have to:
- read in binary data
- match the events together 
- make plots (wired chamber coordinates against ADC values)

My questions about this:
-What's is the fastest way to read in binary data? The flags, the adc
values, the wired chambers coordinates are all u_shorts in the DAQ
software. So I have to read words of 2 bytes.
- I can fill a TNtuple with  the ADC values and an other NTuple with the
wired chambers coordinates. How can I match these NTuples together? 
- Can I do plots out of two NTuples?
- Or is TNtuple the wrong way to solve my problem?



Thank you very much for your help!!

Christian  



-- 
Christian Haeberli                                          
University of Bern
Laboratory for High Energy Physics
Sidlerstr. 5                                                    
CH-3012 Bern



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