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User name Miyoshi
Log entry time 19:11:51 on February21,2000
Entry number 21486
keyword=SSD threshold calibration
SSD external threshold calibration was done.
We use 12 bit CAMAC DAC to change threshold.
When the parameter for DAC is 3079, external threshold is below:
plane 1(FEB #100) : 317.4mV
plane 2(FEB #101) : 317.8mV
plane 3(FEB #103) : 317.6mV
plane 4(FEB #104) : 317.7mV
plane 5(FEB #107) : 317.0mV
plane 6(FEB #108) : 316.0mV
plane 7(FEB #109) : 317.0mV
plane 8(FEB #110) : 317.4mV
plane 9(FEB #114) : 317.2mV
plane 10(FEB #118) : 319.3mV
These values are the same as internal threshold.
We will start taking SSD data at this threshold settings.
When the parameter for DAC is 3899, external threshold is below:
plane 1(FEB #100) : 818mV
plane 2(FEB #101) : 818mV
plane 3(FEB #103) : 818mV
plane 4(FEB #104) : 818mV
plane 5(FEB #107) : 818mV
plane 6(FEB #108) : 816mV
plane 7(FEB #109) : 818mV
plane 8(FEB #110) : 817mV
plane 9(FEB #114) : 816mV
plane 10(FEB #118) : 819mV
By using these values, we decide DAC parameter setting.
For example, we want to go up threshold by 20mV,
we should change DAC parameter 3079 to 3102(3079+33), and so on.
DAC parameter set used when taking data will be included in CRL file(*.crl or *.c).