Difference between revisions of "First look at TOF calibration"

From GlueXWiki
Jump to: navigation, search
Line 28: Line 28:
 
*# plot this time difference vs. paddle number of paddles that got hit in the other plane
 
*# plot this time difference vs. paddle number of paddles that got hit in the other plane
 
*# [[File:PaddleNumber_vs_deltat_example.gif|200px]]
 
*# [[File:PaddleNumber_vs_deltat_example.gif|200px]]
 +
*# again look at each projection and fit the <math>\Delta t</math> peak
 +
*# [[File:deltat_fitposition_example.pdf|200px]] example fit
 +
*# now one can also plot the fit results as a function of paddle number. The inverse slope is the speed module paddle pitch
 +
*# [[File:velocity_example.gif|200px]]
 +
*# one can also plot the difference between symmetric paddles around the beam hole
 +
*# [[File:timediff_planesymmetry_example.pdf|200px]]

Revision as of 15:48, 15 April 2015

First Look

  • first select data sample with the following conditions:
    1. only consider hits within 50ns of the timing peak both for ADC data and TDC data
    2. only consider paddles that have hits on both ends
    3. take care of the 6fold trigger timing shift in the TDC (24ns window)
  • Do a rough determination of the walk correction by using the time in the ADC as reference.
    1. calculate Time difference: \Delta t=t_{{TDC}}^{{i}}-t_{{ADC}}^{{i}}
    2. calculate Integral: I = pulse_integral - pulse_pedestal*nsamples
    3. walk correction fit Note: the minimum ionizing peak is between 6000 and 10000
  • Do mean time comparison between different planes
    1. calculate MeanTime of Paddle i in plane j: MT_{{planej}}^{{i}}=(t_{{right}}+t_{{left}})/2.
    2. calculate MeanTime for all Paddles n in plane k: MT_{{planek}}^{{n}}=(t_{{right}}+t_{{left}})/2.
    3. for each event plot for each paddle in plane k: MT_{{planek}}^{{n}}+MT_{{planej}}^{{i}}
    4. Example mtdiff.gif
    5. fit the meant time peak of each projection:
    6. Fit projection example1.gif example 1
    7. Fit projection example2.gif example 2
    8. Do this for each paddle in the first plane as reference paddle.
    9. Choose one paddle in the first plane as THE REFERENCE PADDLE
    10. Calculate the difference between the fit results of each paddle in the first plane w.r.t. THE REFERENCE PADDLE and fit the distribution
    11. Meantime average to refpaddle example.gif average difference of mean time to REFERENCE PADDLE
    12. Now we have offsets for the Mean-Time for all Paddles w.r.t. THE REFERENCE PADDLE
  • Do time difference comparison of one paddle with the paddle number in the other plane
    1. calculate time difference: \Delta t_{{planej}}^{{i}}=(t_{{right}}-t_{{left}})/2.
    2. plot this time difference vs. paddle number of paddles that got hit in the other plane
    3. PaddleNumber vs deltat example.gif
    4. again look at each projection and fit the \Delta t peak
    5. 200px example fit
    6. now one can also plot the fit results as a function of paddle number. The inverse slope is the speed module paddle pitch
    7. Velocity example.gif
    8. one can also plot the difference between symmetric paddles around the beam hole
    9. 200px