wiki:AnalysisTutorial

This page is far from being complete. While I give an introduction to my students, I try to write down a few notes, hoping that it can serve as a small introduction and help future students.

Analysis Steps

To analyse data, you should be familiar with the following steps:

technical information

set ROOT environment
source /path_to_ROOT/bin/thisroot.sh (you can put this into your .bashrc file)
how to start a macro
go to Mars directory
start root
execute .x path/macro.C("with maybe some variable", 2)
example .x fact/analysis/star.C("/path/sequencefile.txt",5.3,3.2,"inpath","outpath")
or directly root -b -q fact/analysis/star.C\(\"/path/sequencefile.txt\"\,5.3\,3.2\,\"inpath\"\,\"outpath\"\) (-b for without display)
rawdata in wü
/fact/raw/YYYY/MM/DD/YYYYMMDD_FFF.fits.fz
callisto in Wü
/scratch/local/dorner/data.2013.05.11/callisto/YYYY/MM/DD/ (temporary path, will be changed)
star in Wü
/scratch/local/dorner/data.2013.05.11/star/YYYY/MM/DD/ (temporary path, will be changed)
sequences in Wü
/scratch/local/dorner/sequences/YYYY/MM/DD/ (temporary path, will be changed)

callisto

what is done?
calculation of calibration constants, extraction of signal, calibration of data
macro
Mars/fact/analysis/callisto.C
input
sequence file, rawdata (files found with information in sequence file
output
YYYYMMDD_SSS-calibration.root (plots), YYYYMMDD_FFF_C.root (one per run)

star

what is done?
image cleaning, calculation of image parameter
macro
Mars/fact/analysis/star.C
input
sequence file, callisto output
output
YYYYMMDD_SSS-images.root (plots), YYYYMMDD_FFF_I.root (one per run)

merpp

what is done?
merge auxiliary information to data
macro
Mars/fact/analysis/merpp.C
input
sequence file, YYYYMMDD_FFF_I.root
output
YYYYMMDD_FFF_I.root (one per run)

ganymed

what is done?
background suppression, calculation of excess(, energy reconstruction)
macro
Mars/fact/analysis/ganymed.C
input
dataset file, star output (_I.root files)
output
name-analysis.root (result, eventlist after cuts, plots), name-summary.root (event list before cuts)

lightcurve

what is done?
calculation of excess rate
macro
Mars/fact/analysis/lightcurve.C
input
several datasets or information from DB

additional information

sequence
a sequence of runs, consisting of: pedestal run, light pulser run, one or more data runs
dataset
a collection of data runs
YYYYMMDD
night (date of sunset is used)
FFF
file number (starts with 0 every night
SSS
sequence number (number of first run in sequence)

dataset file

a dataset file is a simple text file containing one or more lines as e.g.

/path_to_imageparameter_file YYYYMMDD_FFF_I.root

be aware that there is a space between the path and the file name

in the filename wildcards can be used

exercises A

  1. run callisto for a sequence (check the macro to find out how to call the macro)
  2. run star for the same sequence
  3. run merpp for the same sequence
  4. write a dataset file
  5. run ganymed for this dataset file

Data Check

Understanding the data and selecting only data with good quality is very important.

Available Information

what information does exist to check the data quality?

  • information from the rawdata
  • information from the auxiliary data
  • callisto output
  • star output
  • ganymed output

List of Tools

exercises B

  1. search for some runs affected by lidar
  2. compare star output plots for data affected by lidar with data not affected by lidar
  3. plot image parameters for data affected and data not affected by lidar, as e.g. in https://www.fact-project.org/logbook/showthread.php?tid=1291
  4. redo exercise A5 after selecting only runs with good quality

Understanding the Data

exercise C1

rate scan plot

plot of rates vs time (give time range)

a) explain how the trigger threshold is determined b) explain the structure in the plot rate-vs-time: where do the humps come from? where does the general decline come from?

hints: use visibility tool, 2D threshold plot

Last modified 4 years ago Last modified on Jun 4, 2014, 4:19:13 PM