News-Archive (6/1/03-2/12/04)

02/12/04

A beta version of the new postprocessor xgenesis is available in the third party section. The new versions allows to run the postprocessor in IDL without an IDL license, using the new feature of the IDL virtual machine.

Thanks to the work of Gregg Penn Genesis 1.3 is extended by some features including beam conditioning, uniform energy distribution and initial bunching and energy modulation. The new parameters are:

• CONDITX, CONDITY : conditioning strength in x and y. See the paper by Sessler for more information. Default is 0
• BUNCH, BUNCHPHASE : Initial bunching factor and phase. Default is 0
• EMOD, EMODPHASE: Amplitude and phase of initial energy modulation. Default is 0
• IGAMGAUS: Zero value yields uniform distribution in energy, any other a Gaussian. Default value is 1.

Note that the manual hasn't been updated yet.

11/06/03

The output has been extended to include the phases of the bunching factor of all harmonics. They are enable by setting the bits 20-24 of LOUT.

09/10/03

The BEAMFILE option supports now the specification of the initial angle of the electron slice in units of x' and y'. The columns in the COLUMN statement have to be specified with XPRIME and YPRIME, respectively.

When using external magnet files Genesis required still a dummy specification of a quadrupole lattice according to the stepsize. This has been optimized, so that FL, DL, DRL and F1ST are completely ignored now when the external file has a quadrupole lattice defined.

The feature of FFSPEC has been extended. If has following behaviour:

• FFSPEC = 0 : POW_MID is the on-axis power of the center grid point, integrated over one grid tile, PHI_MID is the phase of the central grid point
• FFSPEC > 0 : POW_MID is the total power in the near field, while PHI_MID is the phase of the central grid point
• FFSPEC < 0 : POW_MID is the on-axis intensity in the far-field, while PHI_MID is the phase of the far field intensity.

The reason is, that POW_MID and PHI_MID were used to calculate the spectrum. The new option of FFSPEC allows to select a specific spectrum.

DISTFILE and BEAMFILE allows a new information line, which has only one argument: REVERSE. If this keyword is specified (e.g. the line is '? REVERSE') Genesis reverse the longitudinal order in the input file.

08/29/03

Because the current implementation of the shotnoise algorithm, based on the method of Penman, does not supply the correct statistics for higher harmonics. Simulations of cascading HGHG FELs can yield a too high shotnoise power level.

A second method is implemented, based on a frequency composed method by Wiliam Fawley, which provides the correct values. It is default for input files with version 1.0 and higher, while the old method can be selected with the new parameter ISNTYP=1.

The new algorithm is a step towards a higher harmonics implementations in Genesis 1.3, which will be available in the future.

Additional new features are the dump on a higher harmonics. For this the parameter IDMPPAR has to be set to the harmonics (e.g. IDMPPAR=3 to convert the phase space distribution to the third harmonics.) Works only with VERSION 1.0 and higher.

Similar a negative value for MAGOUT enforces Genesis to terminate execution after all input files have been processes. Usefull for checking magnetic lattices o external distributions.

06/04/03

Due to a limited time budget of the main author, the SDDS/HDF5 version of Genesis 1.3 will only be available in the C++ version of the code, unless somebody else volunteers to do the work in FORTRAN.

06/01/03

Genesis 1.3 website goes public. Send comment to the webmaster.