Summary: Available on CMS information server IN 2005/042
CMS Internal Note
The content of this note is intended for CMS internal use and distribution only
July 20, 2005
Parallel Dynode Base for HF
J. Olson, U. Akgun, D. Monner, T. Huebner, Y. Onel
Univresity of Iowa, Iowa City, IA52242,USA
Bogazici University, Istanbul, Turkey
HF calorimeter readout system uses 2000 Hamamatsu R7525HA PMTs. In order for the PMT to operate, they
require different voltages on the dynodes of the PMT. Rather than using an independent resistor chain for each
PMT, the production bases installed in HF (called the Parallel-Dynode Bases or PDB) are parallel in design.
The results of the quality control analysis of the production PDB designed at Fermilab are presented here.
For the 2000 Hamamatsu R7525HA PMTs used in the HF calorimeter readout system, the parallel-dynode bases
are used to provide the voltage distribution to the dynodes of the PMTs. The parallel-dynode base (PDB) is an
eight-socket board which uses only one set of series resistor to provide voltage to all eight PMTs on the board.
This base design requires three voltage sources. One voltage source is connected at the top of the resistor chain.