4 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 R∕Q). For many columns of physical quanitities the correct units must be specified.

The allowed column names for the HOM definition file are:

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