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event_filter

S800 data format from Event Filter (S800 Filter)

The purpose of the S800 filter is to parse data from the S800 Event Builder, and reformat them in separated data packets, with an specific structure.

Data from the S800 filter are encapsulated as Ring Items (RI) and, as such, will include a Ring-Item Header, a Body Header, and a Body, where the real parsed data are included. Ring Items emitted from the S800 filter are pushed into a Ring-Buffer called s800filter.

This page describes the data format assembled in the Body of the S800 Filter RI. The data is written in a series of 16-bit unsigned integers, subsequently referred to as words. Regardless of what modules are being read, the Body of the S800 Filter RI will always include four 16-bit words, followed by a series of data packets. The structure of the whole Body is described in the diagram below:

Body Length 1 Body Length 2 S800 Data Tag S800 Data Version Data Packet 1 Data Packet 2
  • Body Length 1: Number of words in body (self inclusive)
  • Body Length 2: Number of words in body - 1 (self-inclusive)
  • S800 Data Tag: 0x5800
  • S800 Data Version: 0x0005

General packet structure

All data is written using the concept of “packets”. The format of a packet is:

Length Packet Tag Packet Data

Length: a count of the number of words in the packet, inclusive of the length word itself

Packet Tag: a predefined integer indicating the type of data found in the Packet Data

Packet Data: the data themselves. These can be data read from the modules or a sub packet. Sub packets have identical structure to main packets. Using this format all data can be placed in nested packets, and coding decisions on how to unpack the Packet Data can be made by examination of the preceding Packet Tag. Packets (including sub packets) can also be skipped by jumping ahead Length words in the buffer.

In this section, each 16-bit word sent by the Filter is described by a 16×3-table diagram. The first row includes the value, either in decimal or hexadecimal format, or a descriptive note. The second row shows the value in binary (“X”s are used to describe arbitrary values that vary from event to event). The last row shows the bit number.

Time-stamp packet

The timestamp is encoded in the XLMV72 time-stamp module for each event as a 64-bit word. The Event Filter parses it as a set of four consecutive 16-bit words.

  • Packet Length (self-inclusive)
6
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5803
0 1 0 1 1 0 0 0 0 0 0 0 0 0 1 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • First 16-bit time-stamp word
First 16-bits “chunk” of time-stamp
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Second 16-bit time-stamp word
Second 16-bits “chunk” of time-stamp
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Third 16-bit time-stamp word
Third 16-bits “chunk” of time-stamp
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Fourth 16-bit time-stamp word
Fourth 16-bits “chunk” of time-stamp
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Event-number packet

The event-number is given by the VMUSB scaler channels as a 48-bit word coded in two 32-bit words. The Event Filter parses it and re-formats it as a three 16-bit words.

  • Packet Length (self-inclusive)
5
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5804
0 1 0 1 1 0 0 0 0 0 0 0 0 1 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • First 16-bit event-number word
First 16-bits “chunk” of event-number
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Second 16-bit event-number word
Second 16-bits “chunk” of event-number
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Third 16-bit event-number word
Third 16-bits “chunk” of event-number
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Trigger packet

The trigger packet includes a bit-pattern word (encoded by the ULM trigger module), with information about what sources triggered the event, and their corresponding time from the Phillips 7186 TDC.

  • Packet Length (self-inclusive)
A number from 2 to 7
0 0 0 0 0 0 0 0 0 0 0 0 0 X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5801
0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Trigger pattern
Bit pattern
0 0 0 0 0 0 0 0 0 0 0 X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

the encoding of the active bits is given by the following table:

Bit Source
0 S800 (from E1 up)
1 Coincidence
2 External 1
3 External 2
4 Secondary (e.g. GRETINA)
  • Trigger time

The time of each trigger source (except for “coincidences”) is given by a word that look like:

Ch time
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

there can be up to four time words (depending on whether time is greater than 0), one for each channel. The channel number Ch is given by:

Ch Source
8 S800 (from E1 up)
9 External 1
10 External 2
11 Secondary (e.g. GRETINA)

Time-of-flight packet

The time-of-flight packet includes all the timing values encoded in the Phillips TDC and the XFP-FP and OBJ-FP ToF from the ORTEC TACs encoded in the S800 Phillips 7164H ADC.

  • Packet Length (self-inclusive)
A number from 2 to 10
0 0 0 0 0 0 0 0 0 0 0 0 X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5802
0 1 0 1 1 0 0 0 0 0 0 0 0 0 1 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Time-of-flight values

The time-of-flight information for each channel is coded in words that look like:

Ch time
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Up to eight of these words can be present (depending on wheter time is greater than 0): six from the Phillips TDC, and two from the XFP-FP and OBJ-FP TACs. The channel number Ch is given by:

Ch Source
6 Phillips TDC time from the A1900 IM2 north scintillator (optional)
7 Phillips TDC time from the A1900 IM2 south scintillator (optional)
12 Phillips TDC time from the RF
13 Phillips TDC time from the OBJ scintillator
14 Phillips TDC time from the XFP scintillator
15 Phillips TDC time from the LaBr (optional)
4 XFP-FP time-of-flight from TAC
5 OBJ-FP time-of-flight from TAC

Note that the time values from the Phillips TDC are subtracted by SpecTcl to the time from the S800 trigger E1 up (encoded in the trigger packet) in order to calculate the corresponding time-of-flight. On the other hand, the times from the TACs (Ch 4 and 5) correspond to actual time-of-flight values.

Scintillator packet

The scintillator packet includes the energy (encoded in the FERA LeCroy module) and time (encoded in the Phillips TDC) of the S800 FP scintillator signals. In the original configuration, there were 3 scintillators (E1, E2, and E3) which were later reduced to just one (E1) after the installation of the Hodoscope.

  • Packet Length (self-inclusive)
A number from 4 to 8
0 0 0 0 0 0 0 0 0 0 0 0 X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5810
0 1 0 1 1 0 0 0 0 0 0 1 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Energy and time values

The energy (from the FERA module) and time (from the Phillips TDC) are given by two consecutive words:

Ch energy
0 0 0 X 0 X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Ch time
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

These words are sent by the Filter as long as energy is greater than 0 or Ch equals 2. The channel assignment given by the Filter is:

Channel Source
0 E1 up
1 E1 down
2 Empty

Ion-Chamber packet

The Ion-chamber packet includes the energies of the 16 ion-chamber segments encoded in one of the Phillips 7164H ADC.

  • Packet Length (self-inclusive)
A number from 4 to 20
0 0 0 0 0 0 0 0 0 0 0 X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5820
0 1 0 1 1 0 0 0 0 0 1 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Sub-packet “Energy” Length (self-inclusive)
A number from 2 to 18
0 0 0 0 0 0 0 0 0 0 0 X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Sub-packet “Energy” Tag
0x5821
0 1 0 1 1 0 0 0 0 0 1 0 0 0 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Energy values

The energy (from the Phillips 7164H ADC module) is given by a series of words that look like:

Ch energy
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where Ch is the segment number (from 0 to 15, being segment 0 the most upstream). The Filter gives an energy word for each segment as long as energy is greater than 0.

CRDC packets

The Filter provides two CRDC packets: one for Cathode Readout Drift Chambers (CRDC)|CRDC1 and one for Cathode Readout Drift Chambers (CRDC)|CRDC2. Each CRDC packet is divided in two sub-packets: the “Raw” sub-packet with information about the pads energies (encoded in the CRDCs XLM72 modules), and the “Anode” sub-packet with anode energy and time information encoded in the CRDCs Phillips ADC. In the following, we describe the structure of the packet provided by the Filter for each CRDC.

  • Packet Length (self-inclusive)
A number from 10 to 330
0 0 0 0 0 0 0 X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5840
0 1 0 1 1 0 0 0 0 1 0 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • CRDC label
0x0000 or 0x0001
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where 0x0000 and 0x0001 identify CRDC1 and CRDC2, respectively.

  • CRDC Sub-packet “Raw” Length (self-inclusive)
A number from 3 to 323
0 0 0 0 0 0 0 X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • CRDC Sub-packet “Raw” Tag
0x5841
0 1 0 1 1 0 0 0 0 1 0 0 0 0 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Global threshold
0x0000
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

This word is reserved for a global threshold; it is no longer used, so it is set to 0

  • Samples sub-packets

The Filter sends a series of sample sub-packets. Each sub-packet consists of two parts. The first part includes one 16-bit word with information about the sample and channel numbers:

control bit sample channel
1 X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where channel is a number between 0 and 63, and refers to a group of four pads. The second part includes up to four consecutive 16-bit words, each with a pad energy greater than 0:

control bit empty connector energy
0 0 0 0 X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

The connector number is related to the pad number (pad) according to: pad = channel + connector x 64 (where connector ranges from 0 to 3, and channel is given by the first word of the sample sub-packet). Note that the Filter processes information from connectors with energies greater than 0.

  • CRDC Sub-packet “Anode” Length (self-inclusive)
4
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • CRDC Sub-packet “Anode” Tag
0x5845
0 1 0 1 1 0 0 0 0 1 0 0 0 1 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Energy from Anode

The anode energy (encoded in the S800 Phillips 7164H ADC) is given by:

empty energy
0 0 0 0 X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Time from Anode

The anode time (from an ORTEC TAC encoded in the S800 Phillips 7164H ADC) is given by:

empty time
0 0 0 0 X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Hodoscope packet

The Filter parses the Hodoscope information encoded in the two Phillips 7164 ADCs and re-formats the data in three packets, two with the energies of the two groups crystals (from 1 to 16 and from 17 to 32), and the third one with the hit pattern recorded in the LeCroy 4448 coincidence-register module.

Each of the two first packets look like:

  • Packet Length (self-inclusive)
A number from 3 to 19
0 0 0 0 0 0 0 0 0 0 0 X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58B0
0 1 0 1 1 0 0 0 1 0 1 1 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Hodoscope Sub-packet “Energy” Tag
0x0000 or 0x0001
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where 0x0000 labels the energy sub-packet of the first group of crystals from 1 to 16, and 0x00001 labels the second group of crystals from 17 to 32.

  • Energy values

The energy from each of the two Phillips 7164H ADC modules is given by a series of words that look like:

Ch energy
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where Ch is the crystal number in the packet (from 0 to 15). The Filter gives an energy word for each crystal as long as energy is greater than 0.

The third hodoscope packet with information from the coincidence register looks like:

  • Packet Length (self-inclusive)
6
0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58B0
0 1 0 1 1 0 0 0 1 0 1 1 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Hodoscope Sub-packet “Hit-pattern” Tag
0x0002
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Hit pattern
hit pattern of first 16 crystals
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
hit pattern of crystals 16 to 32
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Time

The Hodoscope OR time (from an ORTEC TAC encoded in the S800 Phillips 7164H ADC) is given by:

empty time
0 0 0 0 X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

TPPACs packet

The Filter parses and re-formats information from the Tracking PPACs encoded in the XLM72 TPPACs module. The new packet includes both TPPACs; its structure is very similar to that from the CRDCs.

  • Packet Length (self-inclusive)
A number from 5 to 325
0 0 0 0 0 0 0 X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x5870
0 1 0 1 1 0 0 0 0 1 1 1 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • TPPAC Sub-packet “Raw” Length (self-inclusive)
A number from 3 to 323
0 0 0 0 0 0 0 X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • TPPAC Sub-packet “Raw” Tag
0x5871
0 1 0 1 1 0 0 0 0 1 1 1 0 0 0 1
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Global threshold
0x0000
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

This word is reserved for a global threshold; it is no longer used, so it is set to 0

  • Samples sub-packets

The Filter sends a series of sample sub-packets. Each sub-packet consists of two parts. The first part includes one 16-bit word with information about the sample and channel numbers:

control bit sample channel
1 X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where channel is a number between 0 and 63, and refers to a group of four pads. The second part includes up to four consecutive 16-bit words, each with a pad energy greater than 0:

control bit empty connector energy
0 0 0 0 X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

The connector number is defined between 0 and 3, and it is related to the pad number (pad). The value 0 refers to the first 64 pads, and correspond to the strips in the dispersive direction of the first TPPAC. The value 1 is for pads between 63 and 127, and includes the strips in the non-dispersive direction of the first TPPAC. The value 2 corresponds to pads between 128 and 191, which are associated to the strips in the dispersive direction of the second TPPAC. Finally, the value 3 corresponds to pads between 191 to 256, and covers the strips in the non-dispersive direction of the second TPPAC.

The value of pad is given by index + connector x 64, where index is depends on the value of channel and connector according to the table below, where the second column shows the index values for connector=0 or 2, and the third column corresponds to the index values for connector=1 or 3:

channelindexindex
0300
1311
2282
3293
4264
5275
6246
7257
8228
9239
102010
112111
121812
131913
141614
151715
161416
171517
181218
191319
201020
211121
22822
23923
24624
25725
26426
27527
28228
29329
30030
31131
323363
333262
343561
353460
363759
373658
383957
393856
404155
414054
424353
434252
444551
454450
464749
474648
484947
494846
505145
515044
525343
535242
545541
555440
565739
575638
585937
595836
606135
616034
626333
636232

OBJECT PIN packet

The OBJECT PIN packet includes the energy (encoded in the S800 Phillips 7164H ADC measured in the S800 OBJ PIN detector. Note that for most of the experiments, this packet is empty (i.e. it only includes the packet-length and packet tag) because this detector is rarely used.

  • Packet Length (self-inclusive)
A number between 2 and 3
0 0 0 0 0 0 0 0 0 0 0 0 0 X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58A0
0 1 0 1 1 0 0 0 1 0 1 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Energy

The energy from the Phillips ADC is given by one word:

Ch energy
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

where Ch is the Phillips ADC channel reserved for the PIN detector (0). The energy words is sent by the Filter as long as energy is greater than 0.

Galotte packet

The Galotte packet includes up to five time signals from the Galotte detector. These times are encoded in the Phillips TDC. Note that for most of the experiments, this packet is empty (i.e. it only includes the packet-length and packet tag) because this detector is rarely used.

  • Packet Length (self-inclusive)
A number from 2 to 7
0 0 0 0 0 0 0 0 0 0 0 0 0 X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58D0
0 1 0 1 1 0 0 0 1 1 0 1 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Time values

The time information for each of the five detector channel is coded in words that look like:

Ch time
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Where Ch runs from 0 to 3. These words are sent by the Filter as long as time is greater than 0.

LaBr packet

The LaBr packet includes the energy (encoded in the FERA LeCroy module) and times (encoded in a Phillips TDC) from up to four LaBr detectors. Note that although there is a specific EVB tag for that Phillips TDC (0x7187), this module is currently not included in the S800 electronics. As a result, the data packet is empty (i.e. it only includes the packet-length and packet tag).

  • Packet Length (self-inclusive)
A number from 2 to 10
0 0 0 0 0 0 0 0 0 0 0 0 X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58E0
0 1 0 1 1 0 0 0 1 1 1 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Energy and time values

The energy (from the FERA module) and time (from the Phillips TDC) are given by two consecutive words for each LaBr:

Ch energy
0 0 0 X 0 X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Ch time
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Where Ch runs from 0 to 3. These words are sent by the Filter as long as time is greater than 0.

Mesytec TDC (MTDC) packet

The MTDC packet includes the multiple timing values encoded in the Mesytec MTDC. The packet looks like:

  • Packet Length (self-inclusive)
A number from 2 to 10
0 0 0 0 0 0 0 0 0 0 0 0 0 X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Packet Tag
0x58F0
0 1 0 1 1 0 0 0 1 1 1 0 0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
  • Time values

Every time value encoded in the MTDC is sent by the Filter as a series of two 16-bit words: the first one provides information about the MTDC channel and the hit number; the second one gives the time value for that channel-hit. In the current version (Oct. 2015), the Filter processes up to 32 hits per channel. This value can be increased if necessary.

hit channel
0 0 0 X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
time
X X X X X X X X X X X X X X X X
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
event_filter.txt · Last modified: 2018/05/11 15:10 by pereira