Spin Bits

In FY02 run, we had 4 spin bits 

  bit0  1       yellow up
  bit1  2       yellow down
  bit2  4       blue up
  bit3  8       blue down

  spinbit=0        unpol-unpol or unfilled-unfilled
  spinbit=5        Y-up   B-up
  spinbit=6        Y-down B-up
  spinbit=9        Y-up   B-down
  spinbit=10       Y-down B-down
  spinbit=1,2      blue abort gaps
  spinbit=4,8      yellow abort gaps

which gave number from 0 to 15. And we could not tell both-un-filled
bunches(odd number bunches) to unpol-unpol bunches. 

In FY03 run, we got 8 bits (y/b * filled/up/down/unpol) which gives 
number from 0 to 255. If you access from StTriggerDetector::spinBits(), 
you get full information:

  bit0  1       yellow filled
  bit1  2       yellow up
  bit2  4       yellow down
  bit3  8       yellow unpol
  bit4  16      blue filled
  bit5  32      blue up
  bit6  64      blue down
  bit7  128     blue unpol

  spinbit=0       unfilled-unfilled
  spinbit=153     unpol-unpol
  spinbit=51      Y-up   B-up
  spinbit=53      Y-down B-up
  spinbit=83      Y-up   B-down
  spinbit=85      Y-down B-down
  spinbit=3,5     blue abort gaps
  spinbit=48,80   yellow abort gaps

Of course, there are functions which gives each bit with easy to 
remember names, like StTriggerDetector::spinBitBlueDown(), for 
your convenience.

For consistency reason, spin bits from StL0Trigger are still
4 bit converted from 8bit(0-255) and you should expect the
same old spinbits there. In summary:

FY02  StL0Trigger       4bit
FY03  StL0Trigger       4bit

FY02  StTriggerData     not available till re-production of FY02 data
FY03  StTriggerData     8bit