1. Time calibration workshop 1517 May 2017, Amsterdam M. de Jong
Jpp
Time calibration workshop
1517 May 2017, Amsterdam
M. de Jong

2. Preamble (1/2) TDCs are time synchronised time calibration
central clock is broadcast to TDCs
time calibration
fixed time offset for each PMT
pre-deployment calibration
efficient start of data taking
in situ calibration
“self calibrating detector” during envisaged live time of ten years
PMT
time over threshold
discriminator
TDC
time of leading edge
time over threshold

3. time over threshold [ns]
Preamble (2/2)
Rate [a.u.]
arrival time [ns]
time over threshold [ns]

4. Introduction (1/2) Jpp [yi-pee-pee]
an exclamation used to express joy, exultation, or the like
Jpp is a collection of Java inspired C++ interfaces, classes, methods and applications
software development platform for various applications
Jpp consists of various “packages”
organised in corresponding sub-directories and name spaces
most packages can be used without prior compilation
Applications and libraries can be produced with a standard make procedure

5. Introduction (2/2) Available from SVN server $JPP_DIR/software/JXXX
see KM3NeT wiki
$JPP_DIR/software/JXXX
source files (estimated value >3 M€)
$JPP_DIR/examples/JXXX
more than 150 easy-to-read examples
$JPP_DIR/documentation/JXXX
about 20 short documents
Documentation based on Doxygen
generated “on the fly”
also available from Jenkins server

6. User (1/2) Environment Libraries Applications Scripts
source setenv.[c]sh
set PATH and LD_LIBRARY_PATH
[source zshlib.sh or cshlib.csh]
Libraries
predefined symbolic names
Applications
common command line interface (see next slide)
Scripts
option -h will print usage

7. User (2/2) JParser applies to all JXXX applications
-h print help & exit
-h! print default and possible values & exit
-v print SVN revision¶ & exit
-- end of options & continue
--! print actual values & continue
¶ Recently fixed by Kay G.

8. I/O (1/2) typical command line options -f <input file>
-n [<first event>:]<number of events>
-o <output file>
-a <detector file>
"<trigger parameter>=<value>; …"
-P "pmt=<module identifier> <PMT number> <parameter>=value; …"

9. I/O (2/2) data file formats detector file formats
ROOT .root all data types
ASCII .evt Monte Carlo data type
binary .dat internal (~ DAQ data types)
detector file formats
ASCII .detx standard
gendet .det Monte Carlo, only input
binary .dat internal
other input file formats
ASCII .txt trigger, PMT or other parameters

10. Time information (1/3)
JDAQHit { // raw data JPMT_t getPMT() { return pmt; } // index {0, 1, , 30} JTDC_t getT() { return ntohl(tdc); } // [ns] byte swap JTOT_t getToT() { return tot; } // [ns] }; JCalibration { // calibration data : // protected double t0; // [ns]

11. Time information (2/3)
// getXXX converts raw data to calibrated data // putXXX converts calibrated data to raw data template< class T> double getTime( const T& t1, const JCalibration& cal); double putTime( const T& t1, const JCalibration& cal); double getToT( const T& t1, const JCalibration& cal); double putToT( const T& t1, const JCalibration& cal);

12. Time information (3/3) detector data structure O(1) lookup tables
JDetector : std::vector<JModule>
JModule : std::vector<JPMT>
JPMT :
JObjectID
JAxis3D
JCalibration
I/O conform KM3NeT standard
O(1) lookup tables
JModuleRouter::getModule(<module identifier>)
JPMTRouter::getPMT(<PMT identifier>)

13. Time slewing (1/3)
Finite rise time of analogue pulse from PMT to reach discriminator threshold (L0 hit)
simulation
JPMTDefaultSignalProcessor::getRiseTime(double npe);
-P %.slewing=1/0; // default 1
data analysis
JHit::getT();
JHit::setSlewing(true/false); // default true

14. Time slewing (2/3) Bias due to first hit in local coincidence (L1 hit)
Simulation
general detector simulation (km3, KM3Sim, JSirene)
Processing
JHitL1::getT(); // corrected for time slewing
JHitL1::begin()->getT(); // first hit

15. time over threshold [ns]
Time slewing (3/3)
L0 hit
L1 hit
Multiplicity
Dt [ns]
time over threshold [ns]
Dt [ns]

16. Applications (1/3) JDetector create detector
JPrintDetector print detector to terminal
JConvertDetectorFormat convert file format
JCompareDetector compare detector files
JEditDetector edit detector file
JMergeDetector merge detector files
JDrawDetector2D draw footprints (2D)
JDrawDetector3D draw detector in 3D

17. Applications (2/3) JHVTuning JMonitorToT/JFitToT JSlewingK40
tuning of HV / gain
author Alex C.
JMonitorToT/JFitToT
determination of gain and gain spread
author Karel M.
JSlewingK40
determination of time slewing correction
author Maarten de J.

18. Applications (3/3) JMonitorK40/JFitK40 JPulsar
determination of t0 (and TTS, QE) of PMTs inside optical module
author Maarten de J. and Karel M.
JPulsar
determination of t0 of optical modules
author Mieke B.

19. Notes (1/3) JFitToT JTriggerEfficiency JSlewingK40
determination of gain and gain spread based on a model of time over threshold as a function of number of photo-electrons
JTriggerEfficiency
same model is used for simulation of time over threshold as well as time slewing
JSlewingK40
fit parametrisation of time slewing based on real data
result consistent with assumed model

20. Notes (2/3) JPulsar -! "<module ID> <PMT number>; []"
can be used to define which PMT(s) in which optical module should be calibrated
e.g. -! "`cat aap.txt`"
JFitK40 -! "<module ID> <PMT number>; []"
can be used to constrain PMT(s) in fit
e.g. -! "`cat aap.txt`“
JFitK40 -r
revert constraints (useful in conjunction with two step HV tuning)

21. Notes (3/3)
JFitK40 -a <detector file> -A JPulsar -a <detector file> -A
updates detector file with fitted t0 values

22. Examples (1/1) JMonitorK40.sh JSlewingK40.sh JFitToT.sh JPulsar.sh
generate data and fit time offsets of PMTs inside optical module
JSlewingK40.sh
generate data and monitor time slewing
JFitToT.sh
generate data and fit gain and gain spread
JPulsar.sh
example script for application to real darkroom data

23. Summary & Outlook
Jpp is a versatile platform for software developments
Time calibration and time slewing is taken into account in simulation of detector response
Various applications exist for time calibration
Ultimately, time calibration should be obtained from reconstruction of atmospheric muons