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

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 QE/CE + Uniformity (by H.Miyamoto Mons2003/this meeting) Gain/Waveform (by S.Yoshida Mons2003) DOM 2D Scan (Scheduled this year)

Monitoring N2 Scattering by The calibrated tubes Aperture Limiter Energy Meter Reflectors/Attenuators The Absolute QE/CE measurement

Beam PMT Box Chamber Calibration PMTs N 2 laser Rotation Bed Attachment for the IceCube PMT Photon beam with 13 mm diameter scans the cathode

PMT R-guide Rotation-bed UV LED Motor CE Uniformity 2D scan

The Collection Efficiency: Lego plot

SF0030 vs SF0050 SF0016 vs SF0050 Example: The relative Collection Efficiency

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 -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 DOM 2D scan QE/CE + Uniformity The Table data + Interpolation + Normalization By the absolute calibration Charge Response/Waveform GEANT4 Empirical Table

SPE Charge Response S spe (q)~ (1-P e )exp[-q/q  ] + P e N G (q-q 0 /q  )

SPE Charge Response Cont ’ d Some GOOD News q  /q 0, q  /q 0 universally scaling

SPE Charge Response Cont ’ d Some GOOD News Global q  /q 0, q  /q 0  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. CE X Gain 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

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 DOMVGlass.cc DOMVGel.cc GEANT4 DOMVPmtQe.cc DOMVPmtCharge.cc (1-P e )exp[-q/q  ] + P e N G (q-q 0 /q  ) DOMVPmtWaveform.cc

Summary The PMT calibration data is ready for the detector MC Modeling the PMT response was done. A 1 st 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