Difference between revisions of "CERN Prototype"

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* Hadronic showers: older calorimeters had resolution of 80%/sqrt(E). Since sampling fraction in LAr TPC is higher, we are likely to do better than this, but still conservatively assume O(10%)/sqrt. Qualitatively, we can follow arguments similar to the previous item. It follows then that O(10<sup>3</sup>-10<sup>4</sup>) events will be enough for the purposes of this measurement. Indeed, looking at typical test beam and calibration practices (per papers published), we see that 10<sup>4</sup> events is the typical statistics for a given incident beam momentum.
 
* Hadronic showers: older calorimeters had resolution of 80%/sqrt(E). Since sampling fraction in LAr TPC is higher, we are likely to do better than this, but still conservatively assume O(10%)/sqrt. Qualitatively, we can follow arguments similar to the previous item. It follows then that O(10<sup>3</sup>-10<sup>4</sup>) events will be enough for the purposes of this measurement. Indeed, looking at typical test beam and calibration practices (per papers published), we see that 10<sup>4</sup> events is the typical statistics for a given incident beam momentum.
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In summary, depending on case, this part of the measurement program can be accomplished with event sample of the size ~O(10<sup>3</sup>-10<sup>4</sup>), and in some cases less.
  
 
=== PID ===
 
=== PID ===
  
Measuring the "fake" rate, i.e. particle mis-identification,
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Measuring the "fake" rate, i.e. particle mis-identification, is important for certain physics to be addressed by the experiment (cf. proton decay). If the probability of mis-PID is "p", then the statistical uncertainty can be expressed as sqrt(p*(1-p)/n). This can also be understood in terms of precise measurements of "tails" in certain distributions. At the time of writing, we need more guidance in this area, but in general it appears that in this case we would indeed be motivated to take as much data as practically feasible.

Revision as of 23:41, 26 February 2015

Select Documents and Meetings

  • 2015
    • DocDB 10385: Brief review of Computing Requirements for the test

Expected Data Volume

Event Size Estimates

Measurement categories are based on slide 9 in DocDB 9993. Estimated events sizes are based on Monte Carlo simulations run previously for the 10kt version of the Far Detector, and are only meant to be precise within an order of magnitude. However, simple channel count and ADC digitization rate considerations do confirm that this is the right scale for the data produced per event (with zero suppression). Based on a MC data point for electrons (including showers) and experience in uBooNE, we can also conclude that the event sizes for single tracks and showers of comparable total energy (contained in the detector) would not be widely different.

Particle Type Momentum Range (GeV/c) Bin (MeV/c) Approx. event size (MB)


p 0.1-2.0 100 1
p 2.0-10.0 200 5
mu± 0.1-1.0 50 1
mu± 1.0-10.0 200 5
0.1-2.0 100 1
2.0-10.0 200 4
K+ 0.1-1.0 100 1


gamma (pi0) 0.1-2.0 100 1
gamma (pi0) 2.0-5.0 200 5

Statistics

Energy Scale and Resolution

In terms of detector characterization, some of the important parameters include energy scale and resolution for both single tracks and showers - hadronic and EM. Let's consider them first (using comments from T.Junk):

  • Energy scale: for Gaussian distribution, uncertainty will be sigma/sqrt(n). Assuming resolution of 1%, and aiming for ±0.1% precision, only 100 events would be needed.
  • Hadronic showers: older calorimeters had resolution of 80%/sqrt(E). Since sampling fraction in LAr TPC is higher, we are likely to do better than this, but still conservatively assume O(10%)/sqrt. Qualitatively, we can follow arguments similar to the previous item. It follows then that O(103-104) events will be enough for the purposes of this measurement. Indeed, looking at typical test beam and calibration practices (per papers published), we see that 104 events is the typical statistics for a given incident beam momentum.

In summary, depending on case, this part of the measurement program can be accomplished with event sample of the size ~O(103-104), and in some cases less.

PID

Measuring the "fake" rate, i.e. particle mis-identification, is important for certain physics to be addressed by the experiment (cf. proton decay). If the probability of mis-PID is "p", then the statistical uncertainty can be expressed as sqrt(p*(1-p)/n). This can also be understood in terms of precise measurements of "tails" in certain distributions. At the time of writing, we need more guidance in this area, but in general it appears that in this case we would indeed be motivated to take as much data as practically feasible.