====== Top level packet tags ======
The top level packet tags are defined as (C code):
#define S800_VERSION 0x0004
#define S800_PACKET 0x5800
#define S800_TRIGGER_PACKET 0x5801
#define S800_TOF_PACKET 0x5802
#define S800_TIMESTAMP_PACKET 0x5803
#define S800_FP_SCINT_PACKET 0x5810
#define S800_FP_IC_PACKET 0x5820
#define S800_FP_TIME_PACKET 0x5830
#define S800_FP_CRDC_PACKET 0x5840
#define S800_II_CRDC_PACKET 0x5850
#define S800_TA_PIN_PACKET 0x5860
#define S800_II_TRACK_PACKET 0x5870
#define S800_II_PPAC_PACKET 0x5880
#define S800_OB_SCINT_PACKET 0x5890
#define S800_OB_PIN_PACKET 0x58A0
#define S800_FP_HODO_PACKET 0x58B0
====== Detailed description of each packet tag ======
This section gives details on how to unpack the data associated with each packet tag. The format of the data for each packet tag is frozen as of version 4 of the S800 data format. Further modifications to data associated with a particular detector will result in a new packet tag being defined. Please see the [[S800 data format#Versioning system|versioning system]] section for more details.
===== S800_TRIGGER_PACKET =====
Data read from the Lecroy 2367 ULM module and a Phillips 7186H TDC. One trigger pattern followed by up to four times. Format:
0xpppp 0xcttt 0xcttt ...
where p is the trigger pattern, c is the channel within the TDC and t the data.
^ Time data ^ TDC Channel |
|S800 source|8|
|External1 source|9|
|External2 source|10|
|Secondary source|11|
===== S800_TOF_PACKET =====
Times read from both a Phillips 7186H TDC and an Ortec 566 TAC digitized by a Phillips 7164 ADC. Format:
0xcttt ...
^ Time data ^ TDC channel ^ TAC channel |
|RF|12| |
|Object Scintillator|13|5|
|XFP Scintillator|14|4|
|Si|15| |
===== S800_SCINT_PACKET =====
Energies and times of the focal plane scintillator, read from a Lecroy 4300B FERA and a Phillips 7186H TDC. A non-zero energy generates an energy and time pair. Format:
0xceee 0xcttt ...
^ Detector signal ^ Channel |
|E1 Up|0|
|E1 Down|1|
|E2 Up|2|
|E2 Down|3|
|E3 Up|4|
|E3 Down|5|
===== S800_FP_IC_PACKET =====
Zero suppressed energies from the ionization chamber, read from a Phillips 7164 ADC. Format:
0xceee ...
===== S800_FP_CRDC_PACKET =====
Data from the two S800 CRDCs in the form of digitized waveform samples read from the Jtec XLM72V ULM, and anode energies and times read from a Phillips 7164 ADC. These packet data contain sub packets. The S800_FP_CRDC_RAW_PACKET contains the waveform samples and the S800_FP_CRDC_ANODE_PACKET contains the energies and times. Each CRDC is read out sequentially and it's data preceded by an id word. Format:
0x000i subpackets ...
where i is the id number (0 or 1).
==== S800_FP_CRDC_RAW_PACKET ====
Sub packet of [[S800 version 0x0004#S800_FP_CRDC_PACKET|S800_FP_CRDC_PACKET]] giving waveform data. Format:
0xtttt waveform data ...
where t is the threshold. The waveform data is written using two consecutive words per sample, to be upacked from the following format (binary representation):
word 1: hsss ssss sscc cccc
word 2: 0000 nndd dddd dddd
where h is the header bit, which should always be 1 for valid CRDC data;
s are the 9 bits of the sample number (maximum number of samples is 512);
c are the 6 bits of the channel number;
n are the 2 bits of the connector number;
d are the 10 bits of data.
==== S800_FP_CRDC_ANODE_PACKET ====
Sub packet of [[S800 version 0x0004#S800_FP_CRDC_PACKET|S800_FP_CRDC_PACKET]] giving energies and times of the CRDCs. Format:
0xeeee 0xtttt
===== S800_FP_HODO_PACKET =====
Up to 32 Hodoscope energies read from Phillips 7164 ADCs, read in sparse mode, hit patterns read from a LeCroy 4448 Coincidence register, and a time value read from an Ortec 566 TAC via a Phillips 7164 ADC. The type of data to extract is determined from the first word of the packet, the id word. The first 16 energies are associated with id = 0, the second 16 with id = 1 and the hit patterns and time with id = 2. Format:
(id = 0,1) 0x000i 0xceee ...
(id = 2) 0x000i 0xaaaa 0xbbbb 0xtttt
where i is the id, a is the coincidence register A for the first 16 channels, b the register for the second 16 channels and t the TAC time.
===== S800_II_TRACK_PACKET =====
Data from the intermediate image tracking PPAC read from a Jtec XLM72V universal logic module in the form of waveform samples. The S800_II_TRACK_PACKET contains no data and is solely a wrapper for the S800_II_TRACK_RAW_PACKET sub packet.
==== S800_II_TRACK_RAW_PACKET ====
Sub packet of [[S800 version 0x0004#S800_II_TRACK_PACKET|S800_II_TRACK_PACKET]] giving waveform data. Format:
0xtttt waveform data ...
where t is the threshold. The waveform data is written using two consecutive words per sample, to be upacked from the following format (binary representation):
word 1: hsss ssss sscc cccc
word 2: 0000 nndd dddd dddd
where h is the header bit, which should always be 1 for valid PPAC data;
s are the 9 bits of the sample number (maximum number of samples is 512);
c are the 6 bits of the channel number;
n are the 2 bits of the connector number;
d are the 10 bits of data.
===== S800_OB_PIN_PACKET =====
Energy from the object box PIN detector, read out from a Phillips 7164 ADC. Format:
0xceee
===== S800_TIMESTAMP_PACKET =====
A 48 bit timestamp read from a Jtec XLM74 universal logic module. Written as three consecutive words. Format:
0xhhhh 0xmmmm 0xllll
where h are bits 47-32, m are bits 31-16 and l bits 15-0 of the 48 bit timestamp word.