CAMB (Code for Anisotropies in Microwave Background) is a numerical tool designed to best describe anisotropies in microwave background, i.e the first light emitted by the Universe 380.000 years after the Big-bang. This code is avalaible on cosmologist.info website. You will able to find also the theoretical part and the implemented numerical method.
2.Use of CAMB :
Once the archive decompressed, look at the compilation. We can build 2 types of executable : "camb" et "camb_fits". The first is the basics version of the code, which only generates raw output data files. Among these files, the most important is the one which contains temperature as a function of the multipole "l" parameter : "test_scalCls.dat" file by default.
The second one allows to get, with in addition of the previous ones, a FITS formatted output file : "test_scalCls.fits" file by default.
Depending on the version of the code you have, you may experience problems with compilation. For any questions, you can subscribe to the following dedicated forum : cosmocoffee.info, and post into the "Computers and software" part.
3.Results examples :
Below a comparison of three power angular spectrums got by CAMB with WMAP et PLANCK experimental data : the first one represents the concordance model also called ΛCDM model, the second and the third one are Einstein-de Sitter (EdS) model where density is equal to critical density (with Ων=0.12 and ΩQ=0.12), and the two last ones are data collected by WMAP and PLANCK missions.
Here the gnuplot script for plotting the power angular spectrums :