A high-power gas laser pumped by an intense, pulsed, space charge-and current-neutralized ion beam. A high-pressure gas in the laser cavity is ionized by an ion beam. Atomic processes occur which result in a population inversion for the excited states of the gas. Coherent radiation is then emitted by the excited gas atoms in the inverted state. The light is amplified as it traverses the gas. Multiple traversal can be obtained by using an optical cavity comprising mirrors which reflect the light into the excited gas so that the light can be further amplified with each pass through the cavity. Extraction of light energy is done by using a partially transmitting mirror as part of the optical cavity.
A pre-excited excimer laser is formed in a thin flat package. Input X-ray photons which are modulated by passing through a body to be analyzed raise the pre-excited excimer gas molecules to a lasing energy level and the coherent radiation produced is measured and produces an amplified image of the input X-ray photon modulation.