IceCube PMT/Super PMT

DOM acceptance with the super PMT

The DOM acceptance as a function of angle and wavelength are simulated using ROMEO and the GEANT4-based DOMIMANT with the calibration data of the bare super PMTs. They are inputs for the photonics table production as we have done for the regular IceCube DOMs.

The bare PMT data

The PMT has been calibrated with the same procedures with those for Golden PMT calibration. The absolute efficiency was measured at the central region of its photocathode surface. It was then converted to the area-averaged efficiency using the cathode two dimensional scan map. For the photonics table production, we select "ZQ0040" super PMT. The calibration data are plotted below.

Modeling of PMT and DOM

Since the photonics table generation requires the average PMT and DOM behaviors, we constructed the PMT model based on the Chiba's sample data obtained by measurements of more than 100 PMTs. This model then gives the azimuthal-averaged photocathode response map shown below. The ROMEO takes this model data together with the pre-calculated tables by GEANT4 tracing photons propagating in the glass and gel.

ROMEO simulation for the DOM acceptance calculation

Now ROMEO calculates the photon detection probability with every direction and wavelength using the area-averaged absolute QE of "ZQ0040" PMT and the azimuthal-averaged photocathode response of the model PMT. The resultant effective area of the DOM for vertical photons (0 deg) as a function of wavelengths and the relative angular acceptance are displayed below. The area for 400 nm photons increases by 21 % compared to that with the regular IceCube PMT.
Last modified: Sat Feb 23 14:39:32 JST 2008