Contact

Dr. Roland Beyer
PostDoc / Beamline scientist
Nuclear Physics
roland.beyerAthzdr.de
Phone: +49 351 260 - 3281

Structure of the list-mode-data written by MBS

Data acquisition setup for measuring the photon production cross section

One List-Mode-Data (LMD) readout event contains several trigger events. The number of these trigger events depends on the v1495_trig_scal, read_till_end and repeat_readout values in the setup.ini file. Typical values range from 1 up to 512. The actual maximum number of trigger events has to be checked while reading out the LMD file to avoid array overflow.

The event structure depends on the electronics schema used but consists of a number of 32 bit long data words. The type of word is identified by the 5 highest bit the so called GEO. Depending on this GEO the meaning of the different lower bits is shown in the list below.

The single Data words have the following bit-structure:

Time:

GEO = 0  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0 0/1 Time / 100 ms
Bit 26 is 0 for real time and 1 for live time
real and live time are written once only after the stop acquisition signal (trigger type 15) as an end of acquisition flag

Time Flag:

GEO = 1  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 1 Scaler period / ms
The time flag is written as a header for the scaler data block and gives the time between each scaler readout

Scaler Values:

GEO = 4  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 1 0 0 N = number of scaler words following
Subsequent to this single data word N further words are following. Each word contains only one 32 bit value. The meaning of each value is the number of hits counted by the scaler. Note that each scaler channel can be used in scaler or timer mode. In scaler mode the number of rising edges of the input signal are counted. In timer mode the integrated time when the input is high is measured by creating the conjunction of input signal and the internal clock.

consecutive number = scaler ch

Value

0 OR of FPGA input 00-07
1 OR of FPGA input 08-15
2 OR of FPGA input 16-23
3 Coincidence Pl 0
4 Coincidence Pl 1
5 Global OR
6 raw trigger
7 vetoized trigger
8 downscaled trigger
9 FPGA clock
10 FPGA clock AND veto
11 FPGA clock AND NOT veto
12 N.C.
13 veto (timer)
14 not veto (timer)
15 1 (timer)
16 ADC words
17 ADC events
18 QDC1 words
19 QDC1 events
20 QDC2 words
21 QDC2 events
22 TDC words
23 TDC events
24 veto words
25 veto events
26 LMD words
27  
28  
29  
30  
31 target changes
32 FC channel 1
33 FC channel 2
34 FC channel 3
35 FC channel 4
36 FC channel 5
37 FC channel 6
38 FC channel 7
39 FC channel 8
40 LaBr3 1
41 LaBr3 2
42 LaBr3 3
43 LaBr3 4
44 LaBr3 5
45 HPGe 0
46 HPGe 1
47 HPGe 2
48 HPGe 3
49 HPGe 4
50 PTB FC
51 Accelerator
52 SOR (start of readout)
53 TDC gate
54 ADC gate
55 QDC1 gate
56 QDC 2 gate
57  
58  
59  
60  
61  
62  
63  
for the DAQ channels cf. cabeling scheme

Veto scaler:

GEO = 6  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 1 1 0 N = number of veto length values following
Subsequent to this single data word N further words are following. Each word contains only one 32 bit value. Note, that the order of the bytes of these words has to be swapped. The meaning of each value is the length in units of 25 ns of the following signals:

consecutive number

Signal

1 ADC Busy
2 QDC 1 Busy
3 QDC 2 Busy
4 DAQ total dead time
5 Trigger length
6 Veto (total event dead time)

TDC Data:

GEO = 8 1  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 0 0 1 Channel Measurement

TDC Channel

Input

0 FC 1
1 FC 2
2 FC 3
3 FC 4
4 FC 5
5 FC 6
6 FC 7
7 FC 8
8 LaBr3 1
9 LaBr3 2
10 LaBr3 3
11 LaBr3 4
12 LaBr3 5
13 HPGe 0
14 HPGe 1
15 HPGe 2
16 HPGe 3
17 HPGe 4
18 PTB FC
19 N.C.
20 N.C.
21 N.C.
22 N.C.
23 N.C.
24 Accelerator
25 N.C.
26 N.C.
27 N.C.
28 TDC trigger
29 trigger
30 veto = veto start
31 not veto = veto end
for the DAQ channels cf. cabeling scheme

TDC Trailer:

GEO = 8 0  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 0 0 0          Status       Word counter

Trigger Time Tag:

GEO = 9  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 0 1 Time since previous trigger / 800 ns

ADC/QDC Header:

GEO = 10, 12, 14 2  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 1 0 0 1 0 Crate no.     memorized Ch.                

ADC/QDC Data:

GEO = 10, 12, 14 0  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 1 0 0 0 0       Channel Range       UN OV Measurement

Range = 0 is for the low gain value, 1 for high gain
UN = 1 indicates that the value was below the programmed threshold
OV = 1 indicates a dynamic range overflow

Channel

ADC (GEO = 10)

QDC 1 (GEO = 12)

QDC 2 (GEO = 14)

0 HPGe 0  FC 1 LaBr3 1
1 HPGe 1  FC 2 LaBr3 2
2 HPGe 2  FC 3 LaBr3 3
3 HPGe 3  FC 4 LaBr3 4
4 HPGe 4  FC 5 LaBr3 5
5 PTB FC  FC 6 N.C.
6 N.C.  FC 7 N.C.
7 N.C.  FC 8 N.C.

Target Change Flag:

GEO = 28  
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 0 0                                                     new Target

 


Contact

Dr. Roland Beyer
PostDoc / Beamline scientist
Nuclear Physics
roland.beyerAthzdr.de
Phone: +49 351 260 - 3281