Today I finished the OptoCad simulation with practical scenario. I used the real measurement distance for optical components on the bench, and the in-vacuum distance from yuefan's e-log entry 441. I tried also to fine tune(means to move it with like two milimeters) the position of the last infrared lens on the bench. However, the results turn out to be similar with each other when you just look the simulation output picture. And also you can find the output data is similar. For example, the beam size around FI for them are 1.06mm and 1.36mm individualy. See attached file1~4.

However, we can see from the above attached simulation pdf file that the entering beam of PR chamber has some anomalous behaviours. You can see from attached file5, it shows only the incident beam and it is really good. That means bad thing is reflection.  I also checked the output txt file and confirmed the anomalous comes from the reflection of cavity. However, since now I haven't found that why it is like this. I would like to talk with Matteo next week.