Transcript PMT Calibration Results and the MC simulation Shigeru Yoshida, Chiba University

PMT Calibration
Results and the MC
simulation
Shigeru Yoshida, Chiba University
http://www.ppl.phys.chiba-u.jp/
Outline
Overview of the IceCube PMT
calibration for the detector MC
Absolute QE/CE
Uniformity of CE
Charge Resolution/WaveForm
The Response Modeling
A DOM-analog MC prototype
The DOM/PMT calibration
Gain/Waveform
(by S.Yoshida Mons2003)
QE/CE + Uniformity
(by H.Miyamoto Mons2003/this meeting)
DOM 2D Scan
(Scheduled this year)
The Absolute QE/CE
measurement
Aperture Limiter
Reflectors/Attenuators
Energy Meter
Monitoring N2
Scattering by
The calibrated tube
Attachment for the IceCube PMT
Calibration PMTs
Chamber
PMT Box
Beam
Rotation Bed
N2 laser
•Photon beam with 13 mm diameter scans the cathode
CE Uniformity
2D scan
PMT
UV LED
R-guide
Rotation-bed
Motor
The Collection Efficiency: Lego plot
Example: The relative Collection
Efficiency
SF0030 vs SF0050
SF0016 vs SF0050
Charge Resolution/Waveform
In the Freezer
Temp –32degree
PMT Setting in the Freezer
Base circuit
Diffuser attached to UV LED
SPE Charge Spectrum
SPE Waveform
The calibration data for the MC
simulation
The absolute QE/CE data of 4 PMTs now under
measurement
The CE uniformity data of 16 PMTs available
The SPE spectrum and the waveform @ -30C At HV
from 1600V to 2000 V for 4 PMTs
The Gain uniformity data of 1 PMT (possible to add 3
more PMTs)
We are ready to add more PMT data this summer in the
pre-shipping measurement.
The DOM response Modeling
Charge Response/Waveform
The Table data + Interpolation
DOM 2D scan
+ Normalization
By the absolute
calibration
GEANT4
Empirical Table
QE/CE + Uniformity
SPE Charge Response
Sspe(q)~ (1-Pe)exp[-q/qt] + Pe NG(q-q0/qs)
SPE Charge Response Cont’d
Some GOOD News
qt/q0, qs/q0 universally scaling
SPE Charge Response Cont’d
Some GOOD News
Global qt/q0, qs/q0 can reconstruct the
response of ALL PMTs at every gain
And some BAD News…
GAIN seems to have some position dependences….
We see it in the “CE” scan data
.
We may be able to ignore this because…
• so small in terms of AREA
• Simulating MPEs response would be OK
ONLY SPE simulation might be problematic
CE X Gain
SPE Waveform Model
Gaussian fits well!!
SPE Waveform Model
FWHM of a SPE pulse depends on PMT gain.
But the change is small … 200 psec or so
Some Issues and Proposal
Uniformity exhibits significant tube to
tube variance. We do not want to
implement 4800 tables in the DOM MC.
 SIMULATE the response for the broader
light beam as a function of angle and
compare it with the measurement at UW.
Some Issues and Proposal
(Cont’d)
Localized gain variance has been found.
 Use the AVERAGE behavior ?
Some Issues and Proposal
(Cont’d)
Localized gain variance has been found.
 Just ignore it!
DOM Analog MC prototype
DOMVPmtWaveform.cc
DOMVPmtCharge.cc
(1-Pe)exp[-q/qt] + Pe NG(q-q0/qs)
GEANT4
DOMVPmtQe.cc
DOMVGlass.cc
DOMVGel.cc
Summary
The PMT calibration data is ready for the
detector MC
Modeling the PMT response was done.
A 1st prototype PMT MC module is being built
under the root framework
Running this MC would address some
concerns like the tube-tube variance
Please bookmark
http://www.phys.chiba-u.jp/research/IceCube/PMT/