The use of CVD diamond to produce carbon K ultrasoft x-rays.
Carbon K ultrasoft x-rays (278 eV) interact with biological material producing random, isolated tracks of single electrons with a range < 7 nm (cf width of DNA helix approximately2 nm). The electron tracks produced by these ultrasoft x-rays are similar to the numerous secondary electrons and 'track ends' produced by essentially all ionizing radiations. They therefore provide a unique tool in the study of mechanisms of radiation action in the cell. Conventional carbon targets used with the Medical Research Councils cold-cathode discharge tubes have a limited lifetime of 40-50 min. We have investigated the use of thin, freestanding diamond films produced using chemical vapour deposition techniques as a new transmission target for a cold-cathode tube. We present here a novel use of diamond to produce CK ultrasoft x-rays for irradiation purposes. The system described produces an entrance absorbed dose rate to attached cells of approximately 0.2 Gy min(-1) which due to the long target lifetime is usable for low dose-rate CK x-ray studies.
Hill
M A
MA
Medical Research Council, Radiation & Genome Stability Unit, Harwell, Didcot, Oxfordshire OX11 0RD, UK. m.hill@har.mrc.ac.uk
D018130:Diamond; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D018499:Linear Energy Transfer; D010315:Particle Accelerators / Q000295:instrumentation*; D014159:Transducers; D014965:X-Rays
D018130:Diamond