DynamicInefficiencyCMSPixels
https://iopscience.iop.org/article/10.1088/1748-0221/10/05/C05006/pdf
- The sensor efficiency is defined by excluding the following sources of inefficiency: permanently damaged detector parts, modules with readout errors
and Single Event Upsets (SEU).
- The impact of SEUs is minimized by reprogramming the detector during data taking. The SEU is not yet included in the CMS simulation software since it has a minor effect on recorded data
- Excluding all the above efficiency decreasing effects from the measurement, there remains a significant efficiency loss that we call the dynamic inefficiency
- In a series of high multiplicity events, the buffers (mainly data and time-stamp buffers) of the ROC (Pixel readout chip) may overflow, resulting in data losses. The largest part of the inefficiency comes from the overflow of the time-stamp buffers in the double columns. This inefficiency dynamic in the sense that it is not permanent, instead the size of the effect depends on trigger rate, previous and current events