1：Experimental Design and Method Selection:

The study utilized two homemade Coumarine-153 dye lasers as sources of exciting resonance radiation pulses, pumped optically by the third harmonic of a Nd3+:YAG pulsed laser. The setup included an external multichannel generator for timing control and a photomultiplier for signal detection.

2：Sample Selection and Data Sources:

Experiments were conducted with pure ytterbium and its mixtures with buffer gases Ar and Xe at varying pressures and temperatures.

3：List of Experimental Equipment and Materials:

Coumarine-153 dye lasers, Nd3+:YAG pulsed laser (model LS-2145D-C3/2), KDP crystals, electro-optical modulators, multichannel generator (model 9618), photomultiplier, and a personal computer for data analysis.

4：Experimental Procedures and Operational Workflow:

The delay between exciting pulses was varied, and the photon echo signals were detected, converted to digital form, and analyzed. Polarization of the pulses was controlled to study both ordinary and collision-induced photon echoes.

5：Data Analysis Methods:

The relaxation rates and cross-sections were calculated from the photon echo kinetics, considering the isotopic composition of the gases.