1. CLAS12 Timing Calibration
Latifa Elouadrhiri
Jefferson Lab
CLAS Collaboration – CLAS12 Workshop
Jefferson Lab
March 28-31, 2017

2. CLAS12 Equipment 12/3/2018 Forward Detector (FD) Central Detector (CD)
TORUS Magnet
HT Cherenkov Counter
Drift Chamber System
LT Cherenkov Counter
Forward TOF System
Pre-shower Calorimeter
E.M. Calorimeter
Central Detector (CD)
SOLENOID Magnet
Silicon Vertex Tracker
Central TOF System
- Central Neutron Detector
MicroMegas
Forward Tagger
RICH detector
Polarized target
Upgrade Detectors
Forward Tagger (FT)
Ring-Imaging Cherenkov Counter (RICH)
Micro-Megas Detector (MM)
Central Neutron Detector (CND)
12/3/2018

3. CLAS12 Channel Counts Total # of channels: 111831 Sub-System16
Silicon Vertex Tracker
33792
Central TOF 48
High Threshold Cerenkov Counter
Forward Drift Chamber Anodes
24192
Low Threshold Cerenkov Counter
216
Forward Time of Flight(1a, 1b, 2)
1080
PreShower Calorimeter
1152
EM Calorimeter
1296
CND
144
Forward Tagger Calorimeter
332
Forward Tagger Hodoscope
116
Forward Tagger MM
3392
Micromegas
RICH
25024
Total # of channels:

4. CLAS12 Timing Devices Timing System CAEN V1190 (96ps)
Flash-250 ADC
VSM
DCRB MM

5. INL Compensation on the TDC1290 Module
The linearity of the TDC is corrupted. The measured bin size of the TDC module without updating the linearity table - many bins are way off (>5 bins from where they should be). Each bin is about 24ps, so 4 bins is already roughly 100ps error and we are getting more than that for some measurements.
Using Bryan Moffit’s (from DAQ group) routines successful loading of an INL table into the flash memory of the TDC1290 module confirmed its functionality

6. 1190/1290 TDC INL During CLAS12 KPP
KPP Data
1190/1290 TDC INL during next CLAS12 run. Calibration planned before summer
KPP data Calibration can be done off-line

7. FADC250 - Modes • Mode-1: Full waveform.
The FADC250 module samples at 250 MHz, or once every 4 ns, and its firmware can be configured to readout in various modes:
• Mode-1: Full waveform.
• Mode-7: High-resolution time and arithmetic pulse integral, and a pedestal and pulse maximum.
During KPP we used exclusively Mode-1 readout
Implemented offline the same Mode-7 firmware algorithms on Mode-1 data, being tested.
Full waveform allows more precise fit to improve timing and provide input to future firmware, and running Mode for physics run

8. Mode-7 = “High-Res” Timing + Pulse Integral + Event Pedestal
Mode-1 = Full Waveform
Mode-7 = “High-Res” Timing + Pulse Integral + Event Pedestal
In 2015 we used exclusively Mode-1 readout
–  Provides full waveform and allows more sophisticated analysis.
•  Possible to improve timing, pedestal, pulse integrals
•  Provide justification for future firmware upgrades
–  Currently we started with just implementing the same Mode-7 firmware algorithms on Mode-1 data offline in recon
An illustration of Mode-1 readout (full waveform) and Mode-7 readout (in red).

9. The DAQ system: Trigger Interface (TI) board (one per crate) keeps a count of the 250 MHz clock, where the counter is reset at the beginning of each run.
Global system clock vs. CAEN TDC clock. The global system clock is represented by the TI counter and is shown modulo 6. The trigger can come on any edge of the global system clock.

10. Calibration TDC vs FADC (KPP Data)
Time difference between CAEN TDC and FADC-250 for a given channel, summed over all channels, and divided into values of nTI,6
A. Kim

11. FTOF Time walk KPP Data
A. Kim

12. Summary Work just started 2 weeks ago
Working closely with Sergey , Fast Electronics and DAQ groups to complete the calibration before the summer
Coordinate this effort cross the CLAS12 sub-systems
Input the to the FADC firmware
Input to the choice of the FADC running Mode for physics

13. Summary Work just started 2 weeks ago
Working closely with Sergey , Fast Electronics and DAQ groups to complete the calibration before the summer
Coordinate this effort cross the CLAS12 sub-systems
Input the to the FADC firmware
Input to the choice of the FADC running Mode for physics
Use of timing for noise reduction for CLAS12 sub-sytems in general