from gs_skim_b:
1111110000000000 { bit
5432109876543210 { numbers
--------
sssssssdddddmmmm <- bgo-sum-e, other mul, clean mul
abeeeeeeeeeeeeee <- energies (e)
abeeeeeeeeeeeeee
abeeeeeeeeeeeeee
.
srrrrrrriiiiiiii <- detector id's (i)
srrrrrrriiiiiiii and reduced times (r, s sign)
srrrrrrriiiiiiii
from gs_skim_a:
1111110000000000 { bit
5432109876543210 { numbers
--------
sssssssdddddmmmm <- bgo-sum-e, other mul, clean mul
abeeeeeeeeeeeeee <- energies (e)
abeeeeeeeeeeeeee
abeeeeeeeeeeeeee
.
srrrrrrriiiiiiii <- detector id's (i)
srrrrrrriiiiiiii and reduced times (r, s sign)
srrrrrrriiiiiiii
.
00000000tttttttt <- times
00000000tttttttt
00000000tttttttt
This pattern repeats itself in the 16K buffers. The buffers are
padded at the end with zeros, i.e., when a multiplicity of zero is read -
a new buffer should be read.
The first 16bit word of the event contains the clean multiplicity "m", the sum of dirty germanium and clean BGO detectors that fired "d" (other multiplicity) and the sum of energy in the BGO detectors "s" - in the bit-pattern indicated. To get the 'total-multiplicity', add the m-multiplicity and d-multiplicity together.
Then follows m 16 bit words that contains both the germanium energies and side channel information. The first 14 bits are the energies. The meaning of the higher bits are:
ab meaning
-- -----------------------------------------
00 central hit (or no side channel info)
10 side A hit on split detector
01 side B hit on split detector
11 hi res overflow, low-res energy substituted
The following m 16 bit words contains the detector ID's and reduced times. For the reduced time: bits 8 to 14 contains the reduced time value (0...128) and bit 15 (the highest bit) contains the sign of the reduced time. If the latter bit is set, the ge time was early, and if not set, the time was late.
There are eof marks at regular intervals on the tape, of which some (but not all) are associated with eov marks on the data tapes or individual sorts. The extra eof marks are there for timing purposes in subsequent processing.