  Silicon sensors are the go-to technology for high-precision sensors in
particle physics. But only recently low-noise silicon sensors with internal
amplification became available. The so-called Low Gain Avalanche Detector
(LGAD) sensors have been developed for applications in High Energy Physics, but
lack two characteristics needed for the measurement of low-energy protons (<60
keV): a thin entrance window (in the order of tens of nm) and the efficient
amplification of signals created near the sensor's surface (in a depth below 1
um). In this paper we present the so-called proton Low Gain Avalanche Detector
(pLGAD) sensor concept and some results from characterization of the first
prototypes of the sensor. The pLGAD is specifically designed to detect
low-energy protons, and other low-penetrating particles. It will have a higher
detection efficiency than non-silicon technologies, and promises to be a lot
cheaper and easier to operate than competing silicon technologies.
