|20040812||ROMEO ver. 0.91 released|
|20040507||The original ROMEO page uploaded|
A fast and reliable detector simulator is indispensable as well as
full Monte-Carlo simulator, especially for the phase of physics analysis.
While the development of the full Monte-Carlo ray trace simulator for
DOMs(DOMINANT) is underway, we started to develop more handy simulator
Root-based Optical Module EmulatOr)
which simulates the photon propagation inside the DOM sphere and the
PMT response. It would have tables of photon acceptance vs angle of
incidence and timing
have not be implemented yet).
ROMEO is the handy (D)OM simulator based on ROOT/C++ especially tuned to the AMANDA/IceCube (D)OMs. Current version equips only the PMT response module which comprises three sub-modules:DOMPhotoCathode, DOMChargeResponse, and DOMWaveForm.
The current class structure is shown in fig.2. We made a base class for modules named "DOMVModule", currently based on TTask/ROOT. This class would be a wrapper for integration to the IceTray framework.
DOMPMTPhotoCathode module simulates the fluctuation of the collection efficiency. The imput data are generated by DOMINANT as a injection point on the PMT surface. We also measured uniformity of the relative collection efficiency as shown in the central panel of fig.3. The right panel of fig.3 shows an example of resultant photo electron distribution sumpled by Monte-Carlo in ROMEO.
DOMPMTChargeResponse module is based on the charge response functions as shown in fig.4. From our analysis of charge response using single photo electrons, we have learnt that it is PMT gain-scaling and exhibits no variance from tube to tube. For example, relative contribution of the exponential-type component to the main gaussian part, which is parameterized by P_ex, is independent on HV and almost universally same between different tubes as ploted in fig.5. Fig.6 shows a sumpled charge distribution of SPE in the simulation using this model which shows good agreement with our calibration data.
(left: fig5, right: fig6)
DOMPMTWaveForm module simulates the wave form function with a simple gaussian model. Gained charge received from the DOMPMTChargeResponse is converted to the normalization factor of the gaussian assuming the 50 ohm impedance. Fig.7 shows superimposed pulse waves simulated by this module.
How to install the ROMEO
Ray trace&BG sim
PMT Handy c++ sim
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