CMS (Compact Muon Solenoid) - Pixel Tracker

• Today, I want to briefly introduce the pixel tracker of CMS.
  The pixel tracker is the most inner detector of CMS, and has key role to reconstruct track of particle, to calculate the interaction point position, and etc.
  Therefore, I would say that the pixel tracker is the most shiny device of CMS.
• The pixel of pixel tracker is 100 micron * 150 micron size.
  66 million of pixels are on the area about 1 square meter.
• The geometrical setting of pixel tracker is here.
  You can see the three barrel layers which is length is 53 cm, and two disk layers each front and the backward of barrel layers.

• As you can see, disk layers look like turbine. Each wing of disk layer is rotated 20 degree   from the plane which is exactly perpendicular to the z-axis.
  It helps to get better resolution than making the disk layer as flat plane.
• The efficiency when we demand three different layer hit is usable when eta < 2.2.
  Demanding two layers is usable when eta < 2.5.