CCD particle detector simulation
A new CCD detector for the SLAC National Accelerator Laboratory was developed by the MPG HLL . The 3D design simulation for the device was carried out in cooperation with the Weierstrass Institute in Berlin. The surprising result of the simulation was that the CCD was able to store millions of electrons in one pixel instead of the expected few hundred thousands.The numerical simulation covered all operational states of the device:
- charge collection (electrons) from the big silicon volume beneath a pixel structured by the doping and contacts on the top of the silicon waver,
- shifting electrons from one pixel to the next until the end of the detector is reached, where the charge is read out (this was simulated by shifting electrons back and forth between neighboring pixels),
During the shifting any charge losses are forbidden. The electrons are counted before and after shifting them to the neighboring pixel and the precision is set such that relative losses of less then 10-6 still can be quantified, that is less than one electron lost from one million stored.
In the first part of the video, gray is the vertical cut (high density to the left) and yellow is an isosurface of the moving electrons controlled by the boundary conditions which are seen directly in the gray vertical cut on the top. The second part shows the electrostatic potential for the same sequence of operations. The third part shows the electrostatic potential beneath the surface and an isosurface in the shift plane. The electrons are moving from the storage pockets in a vertical channel to the shift plane.