Particle and Radiation Detectors Based on Diamond

Abstract

CVD diamond is a remarkable material for the fabrication of particle and photon radiation detectors. The improvement of the electronic properties of the material has been under intensive investigations and led to the development of a few applications that are addressing specific industrial needs. In particular, we have used diamond layers for industrial applications where it exhibits attractive characteristics as compared with other materials: e.g., radiation and corrosion hardness for a-counters or high gamma-meters at high fluxes; high transparency to low energy X-rays for synchrotron beam line monitoring devices, etc. These specific properties can motivate the use of diamond even though the detection properties remain relatively poor. Indeed, one inherent problem with diamond is the presence of defect levels that are altering the detection characteristics. These are observed in all CVD materials but also in very high quality natural diamonds. They result in unstable responses and carrier losses. Also, it has been observed that high sensitivities may result from the progressive filling of deep levels, e.g. pumping effects, with a detrimental effect on the stability and the response time. Also, the polycrystalline nature is somewhat detrimental as it induces significant non-uniformities of the device response with respect to the position of interaction. We have investigated these features by imaging the response of CVD diamond using a micrometer size focused X-ray beam. The comparison with the grain structure showed that it has a strong influence on the field distribution. We present here recent developments studied at CEA in Saclay for the optimisation of the material with respect to the specific requirements of several applications. They include radiation hard counters; X-ray intensity, shape and beam position monitors, solar blind photodetectors, and high dose rate gamma-meters.

A fast low-noise charged-particle CVD diamond detector

“…The flexibility in choice of electrode geometry allows position sensitive structures on a single detector as well as dose measurements. An overview of properties of CVD diamond detectors can be found in [9] and [10].…”

Hydrogen-terminated boron-doped diamond films under intense gamma irradiation

“…Si, GaAs, and AlGaN [2]. For space or extreme radiation environment applications such as deep UV photodiode (alternatively, visible blind), medical radiotherapy, and novel nuclear micro-battery [3][4][5][6], it is of utmost importance to demonstrate the influence of radiation on materials' structural integrity as well as physical stability. Since the structure dictate materials' physical properties, the assessment of physical properties provides a general guideline helping us to determine the nature of defects and/or structural modification induced due to radiation and its effect on the prototype device.…”

“…Interestingly, we did not observe dramatic change in their structural characteristics with increasing radiation dose in contrast to un-doped non-hydrogenated poly/micro diamond as reported earlier [7], alluding to the stability of H-BDD films which complies with those reported on single crystal diamond [2,5,[7][8] (see Figure 1). A possible explanation is proposed: BDD is conductive throughout, H-terminated diamond is conductive on the surface, but non-H terminated diamond is insulating.…”

Plasmon channels in the electronic relaxation of diamond under high-order harmonics femtosecond irradiation

“…The energy of free electrons resulting from such an excitation is monitored using photoelectron sepctroscopy. We present here first results obtained on diamond, a material that was selected both because of its important applications to detection of ionising radiation [7] which of course involves electron transport -but also because the first ab initio calculations of the electronic lifetimes -which is determined, for its electronic part, by the energy loss mechanisms we discussed above -have been realised, and will be presented below.…”