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Datashape

In this page we explain, based on mingo design, what is the data about, from raw to some options for the possible derived variables.

Raw data

The main variables the detector allows to obtain are times and charges, but the charge calculation comes from the width of the digital signal that is created as a response to the main signal, as it was said in other pages. The data collects, then, time and charge for each side of each strip. These events are saved in T1_F, T1_B, Q1_F and Q1_B, for the lowest layer (we should change this according to the new criteria), etc. A value of time is stored aside with each event information.

Processed data

From this raw data there are some analysis we can perform: some of them are simple and important for monitoring, but we also include other more advanced ideas that can be used to de physics with the telescope.

Standard analysis

  • Position. From the raw data we can obtain information about the location (X,Y) of each event within the RPC active area:
  • X : $(\Delta t \cdot v_p)$ : Time difference (\Delta t) of the timestamps T<n>_F,T<n>_B of the front and back signal, multiplied by the propagation velocity $(v_p)$ of the signal within the strip. Has to be calibrated to take into account the length of the cables and other components which can introduce an offset to $(\Delta t)$.
  • Y : Strip number. The wider strips give lower resolution. This coordinate is much worse than the X.
  • Charge. Information about the charge deposited by the event is coded into the length of the digital pulses generated by the DABC electronic boards. We set a boundary in a reasonable level to consider streamers all the events at its right in the spectrum. However, we have 2 connections to each strip (front and back), and furthermore, we can have multiple hits in different strips within the coincidence window. Thus, the way we select the value of the charge of each event is as follows:
  • For each strip, calculate the average charge Q between the front and back.
  • For each hit within the coincidence window in one RPC, choose the largest Q.
  • Efficiency. For this detector we are calculating the efficiency without taking into account geometric concerns. In order to guarantee with a high degree of certainty that what we are detecting are muons, we acquire data in coincidence mode. This is, we only consider a hit a real event if it gets detected in 3 of the RPC layers, and then we look at the remaining layer. Since we also have information of the location of the hit within the RPC, we can plot a map of efficiency for each RPC. When measuring the efficiency, approximately 1 hour of data acquisition could be sufficient.
  • Rate. The total rate of events given a certain trigger.

Advanced analysis

  • Tracking: angular distribution of cosmic ray incident direction.
  • Multiplicity of the events (just how many particles are involved in each opened time window).
  • Particle discrimination or identification.
  • Time distribution between events, particles, bundles...