Difference between revisions of "2NCorr SPDP Introduction"
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| − | Our array of detectors has a highly non-uniform neutron efficiency and acceptance w.r.t. neutron-neutron opening angle (<math>\theta_{nn}</math>). This is due to the array's non-spherically symmetric geometry, and to its neutron detection efficiency as a function of both particle position and energy (see figure). For this reason, every measured distribution is made meaningful by | + | Our array of detectors has a highly non-uniform neutron efficiency and acceptance w.r.t. neutron-neutron opening angle (<math>\theta_{nn}</math>). This is due to the array's non-spherically symmetric geometry, and to its neutron detection efficiency as a function of both particle position and energy (see figure). For this reason, every measured distribution is made meaningful by normalizing against a "control" distribution. This is done by diving the values of the measured distribution by the control distribution on a bin-by-bin basis. For <math>\theta_{nn}</math>, the control distribution is produced by looking at pairs of pulses, and if there is a neutron event in both pulses, calculate the opening angle between the events. Since no information can be shared between neutrons of different pulses, the control distribution is free of angular correlation, but it's still sensitive to detector array geometry and efficiency as a function of position/energy. Here,"angular correlation" is used to refer to the event rate relative to a completely uncorrelated neutron source. |
| − | [[File:2N Corr OpeningAngleCf252.png|thumb| right|400px| Measured opening angle distribution of uncorrelated neutrons from Cf252 target.]] | + | [[File:2N Corr OpeningAngleCf252.png|thumb| right|400px| Measured opening angle distribution of uncorrelated neutrons from Cf252 target.]] |
Revision as of 22:21, 19 January 2018
Our array of detectors has a highly non-uniform neutron efficiency and acceptance w.r.t. neutron-neutron opening angle (). This is due to the array's non-spherically symmetric geometry, and to its neutron detection efficiency as a function of both particle position and energy (see figure). For this reason, every measured distribution is made meaningful by normalizing against a "control" distribution. This is done by diving the values of the measured distribution by the control distribution on a bin-by-bin basis. For , the control distribution is produced by looking at pairs of pulses, and if there is a neutron event in both pulses, calculate the opening angle between the events. Since no information can be shared between neutrons of different pulses, the control distribution is free of angular correlation, but it's still sensitive to detector array geometry and efficiency as a function of position/energy. Here,"angular correlation" is used to refer to the event rate relative to a completely uncorrelated neutron source.
