An x-ray diffraction system (300; 400) comprising: an x-ray source (302; 402) including a first interchangeable x-ray generating component (303; 403); a second interchangeable x-ray generating component (305; 405) configured to be interchanged with the first interchangeable x-ray generating component; and wherein the first interchangeable x-ray component is a first interchangeable x-ray tube (303; 403) and the second interchangeable x-ray component is a second interchangeable x-ray tube (305; 405); and characterised in that the first interchangeable x-ray tube is configured to emit a first x-ray beam (320; 420) at a first energy and a first wavelength to perform a first non-destructive below surface measurement, wherein the second interchangeable x-ray tube is configured to emit a second x-ray beam at a second energy and a second wavelength to perform a second non-destructive below surface measurement, wherein the first energy is different from the second energy and the first wavelength is different from the second wavelength; further comprising an actuator (308; 408) operatively connected to both the first interchangeable x-ray tube and the second interchangeable x-ray tube for mechanically interchanging the first interchangeable x-ray tube with the second interchangeable x-ray tube; wherein the system further comprises a controller (310; 410) operatively connected to the actuator; and wherein the controller is configured to direct the actuator to interchange the first interchangeable x-ray generating tube with the second interchangeable x-ray generating tube, after the first non-destructive below surface measurement is taken using the first interchangeable x-ray tube based on a first desired crystallographic measurement depth in a sample (314; 414) for the second non-destructive below surface measurement, using the second interchangeable x-ray tube, at a second, different, crystallographic measurement depth. an x-ray source (302; 402) including a first interchangeable x-ray generating component (303; 403); a second interchangeable x-ray generating component (305; 405) configured to be interchanged with the first interchangeable x-ray generating component; and wherein the first interchangeable x-ray component is a first interchangeable x-ray tube (303; 403) and the second interchangeable x-ray component is a second interchangeable x-ray tube (305; 405); and characterised in that the first interchangeable x-ray tube is configured to emit a first x-ray beam (320; 420) at a first energy and a first wavelength to perform a first non-destructive below surface measurement, wherein the second interchangeable x-ray tube is configured to emit a second x-ray beam at a second energy and a second wavelength to perform a second non-destructive below surface measurement, wherein the first energy is different from the second energy and the first wavelength is different from the second wavelength; further comprising an actuator (308; 408) operatively connected to both the first interchangeable x-ray tube and the second interchangeable x-ray tube for mechanically interchanging the first interchangeable x-ray tube with the second interchangeable x-ray tube; wherein the system further comprises a controller (310; 410) operatively connected to the actuator; and wherein the controller is configured to direct the actuator to interchange the first interchangeable x-ray generating tube with the second interchangeable x-ray generating tube, after the first non-destructive below surface measurement is taken using the first interchangeable x-ray tube based on a first desired crystallographic measurement depth in a sample (314; 414) for the second non-destructive below surface measurement, using the second interchangeable x-ray tube, at a second, different, crystallographic measurement depth.