1. MDC Simulation & Digitization
Yuan Ye
BesIII Software Meeting

2. Construction Layer Cell Equal Division Wire Straight Wire
Sensitive Area
Sensitive Area
Straight Wire
Ideal Position

3. Hit Record every hit LayerNo CellNo Edeposit Ddift
Ttof (Global time from event begin)
global 
local

4. Digitization Loop over all hits, combine hits from same
cell to one Digi
Edigi=Edeposit
Ddigi
Energy cut
Now Emin=0, needed T
Do X-T conversion, T =Ttof + Tdrift
Ddrift of minimum T

5. Digitization(Cont.) Smear Get Spatial Resolution from Cal.
x=(f 12+(1-f) 22)1/2
Sample between 1 2 use f
Possible correction: Edigi
Electronic correction 20m:
2= 1,22- electronic2
Sample use 
Ddigi=Ddigi+ Dsmear
If Ddigi<0, do again

6. Digitization(Cont.) X-T conversion Ddigi Tdrift Create Tdigi T to TDC
Tdigi = Tdrift + Ttof + Ttransfer
Possible Correct : Edigi & threshold
T to TDC

7. Multiple Scatter vs Step Limit
@1GeV
StepLimit cm
pt Mev
Now we set default is 2cm

8. Background Two methods: Mix background from data with MC
Add in digitization use some model (done)
Digi mix (future)
Mix background from data with MC

9. Thanks!