The answer to this depends on what you want the .tab FILE for.

For incub8r / levit8r, or 4play / 4dg8r, where you want a lookup-table that does a POSSIBLY non-linear mapping of ADC channels (for the data on TAPE) to (hyper)cube channels, then the simplest solution is to use the program lufwhm. You will need to have some idea of the range of ADC channels that you wish to include in your cube. If you wish to use nonlinear GAINS, you should also have some idea of how the width (FWHM) of the peaks varies with energy; you will need to specify this in terms of parameters like those used to define the starting width in gf3, see gf3.hlp or the escl8r/levit8r NIM paper for details. If you do not want to use nonlinear gains, you can simply enter 

1, 0, 0

as the FWHM parameters, to pretend that you have a constant FWHM of 1 channel.

Lookup-table files can be used for other purposes, however; for example, they are very useful in SCANNING tapes for setting gates on your raw Ge energies to select certain reaction products or bands for selective analysis. It was for this application that the .tab file format was first developed. They can be easily created in gf3 by using the LU and WI commands. You can also display the windows in any .tab file, including those from lufwhm, by using the DW command.

The answer to this depends on what you want the .tab file for.

For incub8r / levit8r, or 4play / 4dg8r, where you want a lookup-table that does a possibly non-linear mapping of ADC channels (for the data on tape) to (hyper)cube channels, then the simplest solution is to use the program lufwhm. You will need to have some idea of the range of ADC channels that you wish to include in your cube. If you wish to use nonlinear gains, you should also have some idea of how the width (FWHM) of the peaks varies with energy; you will need to specify this in terms of parameters like those used to define the starting width in gf3, see gf3.hlp or the escl8r/levit8r NIM paper for details. If you do not want to use nonlinear gains, you can simply enter 

1, 0, 0

as the FWHM parameters, to pretend that you have a constant FWHM of 1 channel.

Lookup-table files can be used for other purposes, however; for example, they are very useful in scanning tapes for setting gates on your raw Ge energies to select certain reaction products or bands for selective analysis. It was for this application that the .tab file format was first developed. They can be easily created in gf3 by using the LU and WI commands. You can also display the windows in any .tab file, including those from lufwhm, by using the DW command.