| Multihit TDCs in the PreSPEC setup (CAENv1290) [message #17372] |
Tue, 07 October 2014 14:18  |
miree
Messages: 71
Registered: June 2014
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continuous participant |
From: *ikp.physik.tu-darmstadt.de
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The CAENv1290 multihit TDC is a very common module in the PreSPEC setup.
In addition, there is more than one way to analyze v1290 data.
This topic is a place to collect successful methods for multihit-TDC analysis.
A CAENv1290 module has 32 channels with 25ps each. The trigger signal, to which the individual channels are referenced, has a resolution of (25ns I believe). You can think about it as if all of the 32channels have a 25ns random jitter. That jitter disappears if you look at differences between two channels. If there are several v1290 in one VME crate, the jitter is common to all channels in all modules, i.e. you can make differences even between channels of different modules.
A nice description of the module can be found in the first part of this document:
http://docs.nscl.msu.edu/daq/samples/CAEN%20V1290/CAEN_V1290_1.0.pdf
If you need really detailed information, read the v1290 manual:
http://www.tunl.duke.edu/documents/public/electronics/CAEN/caen_v1290.pd f
One way to do the reference subtraction: A single channel of one v1290 is said to be the "reference". This reference is then subtracted from all other channels. This is implemented for example in the UTILS.MhTdcPreprocessor (there are other versions of multihit TDC preprocessors around).
It gets some channels from a v1290 module into the input array called "input". It subtracts the value in "reference" from all of the values in "input". The differences are then calibrated (channel into units of ns) and written to the "diff" output array.
Because the active window of the module is very long (typically 10us) and the events of interest are typically within a few hundred ns, it is possible to set a gate around the interesting region in "diff". Every value outside that gate is dropped. All values of "diff" inside that gate survive and will be copied to "ouptut" array after subtracting the left border of the respective gate. Subtracting the gate boundary shifts the outputs in the range from 0 to a few hundred nanoseconds (depending on the size of the gate).
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| Re: Multihit TDCs in the PreSPEC setup (CAENv1290) [message #17811 is a reply to message #17372] |
Wed, 28 January 2015 10:09  |
mlcortes
Messages: 41
Registered: July 2014
Location: Darmstadt
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continuous participant |
From: *ikp.physik.tu-darmstadt.de
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I am trying a way to analyze the MhTDC of the FRS scintillators. The idea is to make all the possible differences between hits in both scintillators and take the first combination that gives a reasonable ToF.
I implemented this in a processor called TofSystemMhTDCSc un the UTILS plugin.
I use it like
processor MhTof/TofSystemMhTDC UTILS.TofSystemMhTDCSc
input_array[0] <- LyccaTargetTofCrate.mhtdc0[16] #Sc21L
input_array[1] <- LyccaTargetTofCrate.mhtdc0[18] #Sc21r
input_array[2] <- LyccaTargetTofCrate.mhtdc0[20] #Sc41l
input_array[3] <- LyccaTargetTofCrate.mhtdc0[22] #Sc41r
reference[0] <- LyccaTargetTofCrate.mhtdc0[31] #Trigger
display hit_mult 100,0,100 in TofSystemMhTDC/Multiplicity
display diff_visu_Tof_Left | time_gate_Tof_Left in TofSystemMhTDC/TofLeft
display SelectedTime_Tof_Left in TofSystemMhTDC/TofLeft
display diff_visu_Tof_Right | time_gate_Tof_Right in TofSystemMhTDC/TofRight
display SelectedTime_Tof_Right in TofSystemMhTDC/TofRight
end
After that I can take the Selected Time for left and right PMT and use the TofSystemTacCal processor.
It is still at testing stage, but maybe someone finds it useful.
Li^2
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| Re: Multihit TDCs in the PreSPEC setup (CAENv1290) [message #18322 is a reply to message #18321] |
Tue, 23 June 2015 10:15 |
Damian Ralet
Messages: 35
Registered: July 2014
Location: Darmstadt
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continuous participant |
From: *dynamic.qsc.de
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Hi Tayfun,
I need to veryfy the lookup table, but from the shape of the signal this really look like the Master trigger signal.
The master trigger is the signal sent to all modules for any accepted trigger. A copy of it is put in one of the MH-TDC channel.
Cheers,
Damian
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