Large area diamond single cristal for High -Luminosity LHC trackers – MONODIAM-HE

In the framework of the High-Luminosity LHC (HL-LHC), it is proposed to build prototypes of particle detectors based on Chemical Vapor Deposition (CVD) monocrystalline diamond of greater dimensions. This generic R&D program aims primarily to evaluate the possible use of these detectors in future physics programs at high intensity and high luminosity.

In this project, all aspect related to the realisation and characterisation of tracking devices based on monocrystalline diamond will be addressed: growth of diamond films with controlled impurities content, surface preparation by plasma and metallisation using various metals, assembly of detectors and connection to read-out electronics, characterisation and tests at various stages of the realisation. Heavy irradiation tests will be perfomed.

One of the main goal of the project is to develop a new lift-off process by mean of ions implantation in order to prepare crystal seeds from the same initial substrate (clones). Using mosaics realised by close-packing such diamond clones, it can be possible to produce monocrystalline diamond films of bigger dimensions. Using this new technique, it is expected that at the end of this project, pixel detectors made on diamond single crystal of bigger dimensions can be realized in a reproducible way for the first time. The quality of theses detectors will be validated using standard High Energy techniques (tests in laboratory and using particle beams, irradiations up to 1016 neq/cm-2). This development may provide the only viable solution for a tracking detector near the collision point for future experiments at very high luminosity.

The character of pluri-disciplinarity of the MONODIAM-HE project has to be emphasised: the partners are issued from two national institutes, IN2P3 and INSIS. The project regroups laboratories having a renowned expertise in all fields required for such developments. The Institut Pluridiciplinaire Hubert Curien and Laboratoire de Physique Subatomique et de Cosmologie have been involved in numerous High Energy collaboration, and are members of the CMS and ATLAS collaboration. The Centre de Recherche Plasmas-Materiaux-Nanostructures (CRPMN) group of LPSC is leader in plasma science and technology. The Laboratoire de Science des Procédés et des Matériaux, formely Laboratoire d'Ingénierie des Matériaux et des Hautes Pressions has been involved for almost two decades in the study of plasma processes and on the synthesis of diamond by microwave plasma assisted CVD. The Institut d'Electronique du Solide et des Systèmes (InESS) has a long lasting experience in the physics and technology of semiconductor devices.

The results of the MONODIAM-HE project, once completed, will have a significant impact on all developments related to future use of diamond detectors in various fields such as nuclear or particle physics, accelerator physics, detection for medical imaging devices or high-power electronics. In case of success, there is no doubt that this project will be a scientific and technological breakthrough in the diamond development and that it will catch the whole academic and industrial community interest. The demonstration and the availability of such crystals should give a real impulse to the wide bang gap semiconductors community allowing the French companies to reach a worldwide leading position.

During the past year, progresses have been achieved by the partners of MONODIAM-HE: LSPM grew CVD monocrystals which have been polished, metallized and tested (structural tests by InESS, CCD measurements by IPHC and LSPM). These tests have shown that these monocrystals have a quality comparable with the best monocrystals realized by the industry. After re-metallization, some of the LSPM monocrystals have been connected to the CMS pixel read-out system and successfully tested in a beam line (at FNAL-USA). In addition, a 7-seeds mosaic has been grown by LSPM, with a thickness (780 µm) never achieved before.