Generation of continuous and pulsed diagnostic imaging x-ray radiation using a carbon-nanotube-based field-emission cathode

TLDR

X‑ray radiation is widely used in medical and industrial applications, yet the basic x‑ray tube design has remained largely unchanged for a century. The study demonstrates that medical diagnostic X‑ray radiation can be generated using a carbon‑nanotube field‑emission cathode. The CNT cathode device produces continuous and pulsed X‑rays with programmable waveforms and repetition rates, achieving >100 kHz pulsed output by gate‑voltage programming. The CNT cathode achieved a 28 mA emission current over a 0.2 cm² area, producing X‑ray intensity sufficient to image a human extremity at 14 kVp/180 mAs, indicating potential for portable and miniature X‑ray sources.

Abstract

X-ray radiation is widely used in medical and industrial applications. The basic design of the x-ray tube has not changed significantly in the last century. In this paper, we demonstrate that medical diagnostic x-ray radiation can be generated using a carbon nanotube (CNT)-based field-emission cathode. The device can readily produce both continuous and pulsed x-rays with a programmable wave form and repetition rate. A total emission current of 28 mA was obtained from a 0.2 cm2 area CNT cathode. The x-ray intensity is sufficient to image a human extremity at 14 kVp and 180 mAs. Pulsed x-ray with a repetition rate greater than 100 kHz was readily achieved by programming the gate voltage. The CNT-based cold-cathode x-ray technology can potentially lead to portable and miniature x-ray sources for industrial and medical applications.