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HOM Definition SDDS File Format
The general SDDS format is defined by two parts, the header and zero
or more data tables. The header contains namelist commands defining,
among other things, the interpretation of the data in the tables. A
table consists of a list of parameters values followed by columns of
data. In the HOM definition file, clinchor requires the presence of
columns Frequency, and any two of ShuntImpedance, Q,
RoQ (the ratio ).
The allowed column names for the HOM definition file are:
- Frequency or f -- Required column. Frequency in
units of Hz or MHz. The program internally converts to Hz.
- ShuntImpedance or R or Rs or Rt --
Required column (see above). Shunt impedance in units of Ohm for
monopole HOMs, and units of Ohm/m for dipole HOMs.
- Q or QualityFactor -- Required column (see above). Quality factor of the resonator.
- ROverQ or R/Q or ROQ -- Required column (see
above). Shunt impedance divided by . In units of Ohm for
monopole HOMs, and units of Ohm/m for dipole HOMs.
- DeQFactor or deQFactor -- Factor by which to reduce the
of the HOM after reading in this file.
- StaggeringStep or staggeringStep or DeltaFrequency or deltaFrequency or df -- Optional
column. Units of Hz only. Default value is 0. If larger than one, then the
frequencies of the NumberOfCavities HOM resonators are staggered
by this interval.
- ShiftToResonance -- Optional column. Default value is
0. If non-zero, then the frequency of the HOMs is shifted to the
closest resonance. If staggeringStep is non-zero, then the
frequency shifting is done after staggering the frequencies.
- NumberOfCavities or NCavities or Cavities or
cavities -- Optional parameter. Default value is 1. If 0,
then this HOM type is not used in the calculation. If greater than
one, then the HOM resonator is duplicated numberOfCavities times.
Here is an example of an SDDS HOM definition file for the APS ring cavities:
SDDS1
&description text="APS cavity longitudinal HOMs" contents="HOM definition" &end
&column name=Frequency, symbol=f, units=Hz, type=double,
description="Resonant frequency of HOM resonator" &end
&column name=ShuntImpedance, symbol=R, units=Ohm, type=double,
description="Shunt impedance of longitudinal HOM resonator" &end
&column name=Q, symbol=Q, units="", type=double,
description="Q of longitudinal HOM resonator" &end
&column name=NumberOfCavities, symbol=N$bcav$n, units="", type=long,
description="Number of cavities for each HOM" &end
&column name=StaggeringStep, units=Hz, type=double,
description="Staggering frequency steps between cavity HOMs" &end
&column name=ShiftToResonance, type=long,
description="flag causes automatic shift to resonance after Staggering" &end
&data mode=ascii, noRowCounts=1 &end
558.7e6 13.6e6 68e3 16 -0.08e6 0
761.1e6 25.6e6 53e3 16 -0.7e6 0
962.0e6 6.1e6 54e3 16 -1.2e6 0
1017.4e6 2.6e6 41e3 16 -1.7e6 0
1145.1e6 2.7e6 92e3 16 -1.5e6 0
1219.2e6 3.6e6 41e3 16 -1.9e6 0
Next: Example Files
Up: User's Guide to Program
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Randy Flood
2006-11-06