Alpha particle x-ray spectrometer question

[Bill_CA]

Are there any natural or man-made materials (elements, compounds, polymers) that could be placed under an alpha particle x-ray spectrometer head and give no reading? I.E. the test material would gave off no natural alpha particle radiation or x-rays from being bombarded by the emitted alpha particles from the instrument's radioactive Cerium-244 source.

Thanks

Bill