DRS4 Forum
  DRS4 Discussion Forum, Page 44 of 44  Not logged in ELOG logo
ID Date Authordown Subject
  573   Tue Nov 29 23:19:06 2016 Abhishek RajputPotential Incorrect Timing Calibration for DRS4 Data

Hello Stefan,

Thank you for the excellent explanation and diagram. This part of the code is now much clearer to me.

My other questions pertain to the "trigger cell". Firstly, what precisely does this mean? Moreover, how does the "trigger cell" relate to the trigger time delay we can set in the DRS4 application? This is causing some confusion for me, because regardless of where you set the trigger time delay on the DRS4 application, there are still points on the waveform that are saved prior to the moment in time when a pulse exceeds some voltage threshold we set in the application. I get the impression that "trigger delay" and "trigger cell" are unrelated concepts, so any clarification you can provide would be greatly appreciated.

Abhishek

Stefan Ritt wrote:

The code in the macro is correct. The misconception lies in the definition what "sample 0" means. Please view the attached picture. This is simplified case with a DRS chip with only 8 cells (instead of 1024). There are two events (blue and red). In the first event, the chip is stopped at trigger cell (tc) 2, in the second case at 5. Since the readout starts with the trigger cell, the first readout sample in the first event belongs to cell #2, the next one to cell #3 and so on. In the second (red) case, the first sample belongs to cell #5, the second to cell #6 and so on. "Aligning cells 0" now means that the physical cell 0 (not the readout sample) is aligned for each channel. In the first event, the 7th readout sample will have the same time in all channels, in the second event the fourth readout cells will have the same time. This is because physical cell #0 is always at different places inside the readout array.

Stefan

Abhishek Rajput wrote:

Hello,

I was running through a particular binary file containing data taken on all 4 channels of the DRS4 and printing out the value of the first time sample for each channel (per event). While doing so, I noticed that some of these times were negative. For this dataset, channel 1 was chosen as the reference channel (which is the default setup in Stefan's DRS4 macro).  From my understanding, the calibration procedure delineated in the DRS4 manual and shown in the code below is supposed to sync the timing of each channel relative to sample 0. However, this does not appear to be the case for when I print out the time value of the first sample, I notice that only channel 1's 0th sample is set to 0. The first sample for the other channels is nonzero (and most often negative). 

Even more strange is when I test another 4-channel dataset with the same code, this issue does not appear. More specifically, the first time sample on each waveform on all channels is set to 0, as should be the case.

My question is therefore whether or not the timing calibration varies from dataset to dataset. My initial thought was that this should not be the case, but I have two different data sets taken on the same set of channels which give different timing calibration results. Are there any circumstances under which this behavior can happen? 

for (ch=0 ; ch<5 ; ch++) {
         i = fread(hdr, sizeof(hdr), 1, f);
         if (i < 1)
            break;
         if (hdr[0] != 'C') {
            // event header found
            fseek(f, -4, SEEK_CUR);
            break;      
         }
         chn_index = hdr[3] - '0' - 1;
         fread(voltage, sizeof(short), 1024, f);
         
         for (i=0 ; i<1024 ; i++) {
            // convert data to volts
            waveform[chn_index][i] = (voltage[i] / 65536. - 0.5);
            
            // calculate time for this cell
            for (j=0,time[chn_index][i]=0 ; j<i ; j++)
              time[chn_index][i] += bin_width[chn_index][(j+eh.trigger_cell) % 1024];            
         }
      }
    
      // align cell #0 of all channels
      t1 = time[0][(1024-eh.trigger_cell) % 1024];
      for (ch=1 ; ch<4 ; ch++) {
         t2 = time[ch][(1024-eh.trigger_cell) % 1024];
         dt = t1 - t2;
         for (i=0 ; i<1024 ; i++)
            time[ch][i] += dt;
      }

 

 

  580   Fri Dec 9 04:17:46 2016 Abhishek RajputPotential Incorrect Timing Calibration for DRS4 Data

Hello Stefan,

Many thanks for the explanations. You've cleared my confusion in this matter.  

Abhishek Rajput

Stefan Ritt wrote:

The inverter chain in the DRS4 is continously running in a ring. Once you get a trigger, it is stopped. This happens in any of the 1024 cells. The last cell which sampled a signal plus ne is called "trigger cell". In the previous diagram in event #1, the last cell sampling was "1", so the trigger cell is "2". In event 2 (red case), the trigger cell is 5. If you would run like this, you see only the part of the waveform BEFORE your trigger (since the DRS4 is continously sampling and is stopped with the trigger). In order to see the full peak of your waveform, you can apply some external trigger to shift the trigger position to the right. This is done in the FPGA reading out the DRS4 chip. If your peak is let's say 20 ns wide, and you delay your trigger by 30 ns, you see the peak plus 10 ns right of the peak.

Stefan

Abhishek Rajput wrote:

Hello Stefan,

Thank you for the excellent explanation and diagram. This part of the code is now much clearer to me.

My other questions pertain to the "trigger cell". Firstly, what precisely does this mean? Moreover, how does the "trigger cell" relate to the trigger time delay we can set in the DRS4 application? This is causing some confusion for me, because regardless of where you set the trigger time delay on the DRS4 application, there are still points on the waveform that are saved prior to the moment in time when a pulse exceeds some voltage threshold we set in the application. I get the impression that "trigger delay" and "trigger cell" are unrelated concepts, so any clarification you can provide would be greatly appreciated.

Abhishek

 

  487   Thu Mar 31 19:30:26 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

  489   Thu Mar 31 19:44:38 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Stefan Ritt wrote:

No. You have to use an inverter for one of your signals.

Stefan

Abaz Kryemadhi wrote:

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

 

 

  491   Thu Mar 31 20:38:05 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

Thanks, that looks just fine.

Stefan Ritt wrote:

Here is one (SI 100): https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups

Abaz Kryemadhi wrote:

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Stefan Ritt wrote:

No. You have to use an inverter for one of your signals.

Stefan

Abaz Kryemadhi wrote:

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

 

 

 

 

  493   Fri Apr 1 01:30:40 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

Hi Chris,

 I am looking at Sensl SiPMs as well,  can you send the part number from Coilcraft?

Thanks!

Abaz

Chris Thompson wrote:

I needed a fast pulse inverter in order to feed signals from the recent SensL SiPMs into a conventional CFD which only accepted negative signals. I got a very small ferite torridal transformer from Coilcraft and wired up to invert signals then inserted into in 50 ohm coax cable and it works fine. These things cost only a few cents each!

Abaz Kryemadhi wrote:

Thanks, that looks just fine.

Stefan Ritt wrote:

Here is one (SI 100): https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups

Abaz Kryemadhi wrote:

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Stefan Ritt wrote:

No. You have to use an inverter for one of your signals.

Stefan

Abaz Kryemadhi wrote:

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

 

 

 

 

 

 

  497   Sat Apr 2 17:22:34 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

Thanks again,   this is very useful,  just another question did you put any other passive elements in the circuit for inverting the signal or just simply swaped the transformer connections? 

Chris Thompson wrote:

The coilcraft part number is: JA4220-ALB. Iordered two of them and they were sent as free samples. You might want to buy some slightly bigger ones. I found them so small it was very hard to solder the coax cable to the connectors. Since I got them, I managed to damage one as they are quite fragile! In the confirmation email I got there was some contact info which may be useful for you: "For help, contact Victoria Berner at 847-516-5551  vberner@coilcraft.com "  BTW every time I use this forum I'm told that my password is not valid. Each time I reset it according to the "Lost pasword preceedure. Then I can log on again. Its quite annoying.

Abaz Kryemadhi wrote:

Hi Chris,

 I am looking at Sensl SiPMs as well,  can you send the part number from Coilcraft?

Thanks!

Abaz

Chris Thompson wrote:

I needed a fast pulse inverter in order to feed signals from the recent SensL SiPMs into a conventional CFD which only accepted negative signals. I got a very small ferite torridal transformer from Coilcraft and wired up to invert signals then inserted into in 50 ohm coax cable and it works fine. These things cost only a few cents each!

Abaz Kryemadhi wrote:

Thanks, that looks just fine.

Stefan Ritt wrote:

Here is one (SI 100): https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups

Abaz Kryemadhi wrote:

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Stefan Ritt wrote:

No. You have to use an inverter for one of your signals.

Stefan

Abaz Kryemadhi wrote:

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

 

 

 

 

 

 

 

 

  499   Sun Apr 3 22:34:28 2016 Abaz KryemadhiTrigger on the And of a positive and negative signal

Thanks, great!

Chris Thompson wrote:

No there are no other components. I put a photo of the inverter with its cables SMA and one end, BNC at the other. You can see it is very small. I glued the inverter to a piece of thin plywood, and fixed the cables to it before attempting to solder them to the pads on the ferite bead support

Abaz Kryemadhi wrote:

Thanks again,   this is very useful,  just another question did you put any other passive elements in the circuit for inverting the signal or just simply swaped the transformer connections? 

Chris Thompson wrote:

The coilcraft part number is: JA4220-ALB. Iordered two of them and they were sent as free samples. You might want to buy some slightly bigger ones. I found them so small it was very hard to solder the coax cable to the connectors. Since I got them, I managed to damage one as they are quite fragile! In the confirmation email I got there was some contact info which may be useful for you: "For help, contact Victoria Berner at 847-516-5551  vberner@coilcraft.com "  BTW every time I use this forum I'm told that my password is not valid. Each time I reset it according to the "Lost pasword preceedure. Then I can log on again. Its quite annoying.

Abaz Kryemadhi wrote:

Hi Chris,

 I am looking at Sensl SiPMs as well,  can you send the part number from Coilcraft?

Thanks!

Abaz

Chris Thompson wrote:

I needed a fast pulse inverter in order to feed signals from the recent SensL SiPMs into a conventional CFD which only accepted negative signals. I got a very small ferite torridal transformer from Coilcraft and wired up to invert signals then inserted into in 50 ohm coax cable and it works fine. These things cost only a few cents each!

Abaz Kryemadhi wrote:

Thanks, that looks just fine.

Stefan Ritt wrote:

Here is one (SI 100): https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups

Abaz Kryemadhi wrote:

Ok, thanks!  do you know an easy in-line inverter like mini-circuit or digikey?    Can also redesign the detector I gues to produce positive signals, just it might be easier if there was a simple inverter if you are aware of? thanks Abaz

Stefan Ritt wrote:

No. You have to use an inverter for one of your signals.

Stefan

Abaz Kryemadhi wrote:

I would like to be able to trigger in this fashon:  channel 0 > 0.1 and. channel 1< -0.1,  because I have a positive and a negative signal.  Can DRS4 (5) Eval board do this kind of trigger?

Thanks!

Abaz

 

 

 

 

 

 

 

 

 

 

  517   Wed Apr 27 20:04:12 2016 Abaz KryemadhiBest settings for time measurements

I am studing some pulses that are about 200-300 ns wide and a rise time of few ns,    which settings would be best for coincidence time measurements?

In some preliminary work I found for 700 MegaS the time measurement is better without time calibration (in -0.05 to 1V) rather than with time calibration in -0.5 to 0.5,  my pulses are about 60 mV.   Is it expected that always with time calibration time accuracy would be better or depends?   

Also I use this code snippet to find time for channel 1 and the same idea for chan. 2.

// find peak in channel 1 above threshold
      for (i=0 ; i<1022 ; i++)
         if (waveform[0][i] < threshold1 && waveform[0][i+1] >= threshold1) {
            tt1 = (threshold1-waveform[0][i])/(waveform[0][i+1]-waveform[0][i])*(time[0][i+1]-time[0][i])+time[0][i];
            break;
         }

 

Thanks!

Abaz

  727   Tue Jan 29 14:43:44 2019 Abaz KryemadhiROOT Macro for data acquired with the newest software

Hello,

Is there a root macro for decoding binary data acquired with the newest software for single board or multi-boards daisy chained?

Cheers,

Abaz

  747   Fri Mar 8 19:35:11 2019 Abaz KryemadhiROOT Macro for newest software

The older root macro did not work for me for data acquired with the newest software.

so for the newest software and multiple boards, I modified the read_binary.cpp into read_binary.C for those who like to use the root macro, see the attachment.  

 

  827   Tue May 4 21:18:28 2021 Abaz Kryemadhirecording only timestamp and amplitude and/or filesize maximum

Hi,

I have been collecting some date using the DRS4 board at a trigger rate of 10-20 Hz,    I only need the timestamp and the amplitude, is there anyway to select only these two live as the data comes in to be stored. 

Alternatively,  What's the maximum file size or maximum number of events I can store in one binary file in linux. 

Thanks,

Best,

Abaz

ELOG V3.1.4-bcd7b50