1. pCVD diamond J. Buytaert

2. some interesting facts The sales of synthetic diamond material overtook that of natural industrial diamond products as long ago as 1978. In 2000 world consumption of industrial diamond passed the one billion carat milestone. cvd diamond often quality exceeds natural diamond properties, less or controlled impurities. cvd apparatus are now quite common and ‘affordable’. quality grades : “thermal” (‘cheap’) and “optical”(‘more expensive’). But, unfortunately high thermal (K>1800 W/Km) quality == optical quality ! price high thermal quality: –online quote “TM180” from Elementsix,Ltd : 1cm^2, 250um = 85 euro. –‘price indication’ (Diamond materials) : 80 mm disk, 250um : ~3000 euro. (~60 e/cm^2). grow rate 1-2 um/hour. (150um -> 1week !)

3. ‘Diamond materials’ company 1 day visit. small spin-off from Fraunhofer institut, Freiburg, Germany. –started in 2004, 8 engineer/physicist. –small production capacity at the moment.(13 ovens), aimed at optical quality. –also produce patented cvd equipment; “P30” oven –can gear-up production rapidly. –research oriented, very interested in new applications. –have contacts with Dulinsky (strasburg, mimosa) and H. Kagan

4. ‘Diamond materials’ company. have all processing steps in-house: –grinding, polishing –laser cutting –metallization –quality control –mounting techniques 20 years of research experience on cvd diamond. ‘ideal’ developing partner ?

5. ‘Diamond materials’ company. learned: –that Velopix module concept is very ‘viable’ (geometry, cutting, thermal aspects). –currently limited to 80mm disks. They are developing 150mm oven. –80 mm/ 250 um disk feels like a ‘rigid plastic’: quite resilient/flexible. –80 mm disk has typically 0.5mm out-of plane ‘bowing’ in center. depends on thickness. 150 um ? can be flattened by constrain. No risk for breaking. Disappears when cut. probably inherent to poly-crystalline cvd technique : unequal grain structure on nucleation and grow side. All manufactures. –diamond can be brazed to metals (Cu) and diamond ! Interesting for mechanical construction and cooling interfaces !

6. Degradation of thermal conductivity with irradation ? 33rd EPS Conference on Plasma Phys. Rome, 19 - 23 June 2006 ECA Vol.30I, P-1.119 (2006). Radiation-hard ceramic materials for Diagnostic and Heating and Current Drive systems for ITER. we agreed with Diamond materials on an irradiation of a sample. They can measure thermal ‘in-plane’ conductivity with 2 mm resolution.

7. Elementsix,Ltd (UK) World leader in industrial CVD diamond. Also strong research branch. –provide detector grade diamond to RD42 –“DIAFILM TM180”: should ask for large dimensions. –“ScD Thermal”: silicon-carbide-diamond ?

8. Further: At CERN other groups are interested in pCVD diamond for low-mass mechanical, cooling substrate: –NA62 Gigatracker ( in contact with A. Kluge, P. Riedler, G Nuessle). –cooling section PH/DT (R. Dumps, P. Petagna): plan to setup evaluation stand. University of bristol : http://www.chm.bris.ac.uk/pt/diamond/ http://www.chm.bris.ac.uk/pt/diamond/

9. Immediate plans: build ‘thermal study module’: 1 Medipix/Timepix on CVD substrate, with cooling interface in vacuum, with PH/DT. Readout compatible with USB module. contact Elementsix. irradiation test for thermal conductivity degradation ( April 2010)