Proton Calorimetry/Equipment/QuARC General Information
QuARC Information Summary
1. Scintillators
The main properties of our scintillators are:
- ρ = (1.03±0.01)g cm-3
- decay constant = 2.5 ns
- maximum emission at 425 nm (blue-violet)
- light output = 56% of anthracene
- n = 1.57
In total we have 302 scintillator sheets. Their production mechanisms and average thicknesses are summarised in this file []. The order in which the scintillators are assembled in each stack is available in the GUI, inside every experimental run log.
- Each sheet thickness is measured in 8 different points of the scintillator: 4 corners, and 4 middle parts of each side.
- The uncertainty is simply calculated as the standard deviation.
- For the scintillator stacks used in Manchester and PARTREC we measured the thickness in 3 points.
- Clear polished scintillators (machine block) offer the best light output.
2. Photodiodes
The first prototype of the QuARC had a CMOS sensor, but it was then upgraded to photodiodes coupled to each sheet individually. There is a direct coupling, so no optical gel is used.
- Model = hamamatsu S12915-16R
- Effective photosensitive area = 6.0 mm2
- Spectral response wavelength between 340-1100 nm
- Quantum efficiency peaks at 960 nm
3. Boards: DDC232
We have two different types of boards (revB and revC) that differ in the number of PD and the space between them. They are directly coupled to the PD, and need a power cable and a PMOD connection that goes to the FPGA.
- revB: 16 photodiodes, spaced 2.86 mm. Uses 12V power cable.
- revC: 32 photodiodes, spaced 3.0 mm. Uses 7V power cable -> revD is a modification of revC, with a change in the heat management.
4. FPGA
The FPGA is used to read the boards and transfer the data to the PC. The FPGA automatically loads the last code designed, but if not we can load it with Vivado: the code used is FTDI.h, which uses libFTDI libraries so they need to be installed in the laptop. We have 2 different boards:
- Nexys board:
- usb104: powered via USB and connected to the board with a PMOD cable.
If we want to run the DAQ, first we have to compile the code as follows:
MacBook: g++ -L/opt/local/lib -I/opt/local/include/libftdi1 -lftdi1 -std=c++17 -O3 FTDI.cpp -o FTDI Nuc PC: g++ -L/usr/lib64 -I/usr/include/libftdi1 -lftdi1 -std=c++17 -O3 FTDI.cpp -o FTDI
We can then run the code with the adequate parameters:
./FTDI nexys/usb104 num_DDCports FSR t_INT(us) nmeasurements outputfile board (testmode)
We can also visualise "live" (reads from average.csv) using the livePlot code.
g++ -o livePlot livePlot.cpp `root-config --cflags --glibs` -O3
./livePlot num_DDCboards FSR yScale revB/C reversetrue/false (clean folder background.txt backST.txt frontST.txt ...)
5. Data acquisition
Running FTDI code the average time per read should be ~170us, giving a data transfer speed of ~0.47MB/s.
- We acquire data using FTDI.cpp code, changing the output file to Run001.txt, Run002.txt and so on.
- If we want to acquire data and show it live we need to use progh.sh
./prog.sh nexys/usb104 4 350 0 170 100000 50 true capture.txt revB/C true/false (fit/test/clean) (folder background.txt backST.txt frontST.txt ...)
6. Data analysis
Questions
- Boards: What needs to be done to them? Vivado codes into FPGA but boards? Daisy chaining? What was done in terms of usbC connection?
- FPGA: no longer using nexys? What issues did we have with both of them?
- Experiment: just use FTDI code changing the run number? where are these runs saved? Possible errors during data acquisition? test mode?
- Data analysis: parameters for fit based on what?