20 research outputs found
Combined acoustic and optical trapping
No full textCombining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, comparatively large particles. With conventional approaches it is difficult to fully employ the strengths of each method due to the different experimental requirements. Here we present the combined optical and acoustic trapping of motile micro-organisms in a microfluidic environment, utilizing optical macro-tweezers, which offer a large field of view and working distance of several millimeters and therefore match the typical range of acoustic trapping. We characterize the acoustic trapping forces with the help of optically trapped particles and present several applications of the combined optical and acoustic trapping, such as manipulation of large (75 ?m) particles and active particle sorting.© 2011 OSA<br/
PO-0795: Comparison of Service graph log and Dynamic linac log of Elekta Linacs for patient QA
No full textA windowless high power diffraction tube with Si anode for the efficient excitation of low Z elements for TXRF
No full textA WINDOWLESS HIGH POWER DIFFRACTION TUBE WITH SI ANODE
FOR THE EFFICIENT EXCITATION OF
LOW Z ELEMENTS FOR TXRF
Th.Meinschad1, Christina Streli1, P.Wobrauschek1, Ch. Eisenmenger-Sittner2,
1Atominstitut, Univ. of Technology, Vienna, Austria
2 Inst. of condensed matter, Vienna Univ.of Technology, Austria
To excite low Z elements efficiently low energy photons are required, specially to detect Al and Na on Si wafer surfaces photon with an energy below the Si ?K edge but above the Al-K edge. Using synchrotron radiation is the most effective way but also for lab scale instrumentation there are some approaches. Besides W-M lines also the use of Si K line is possible. An additional problem is the fact that total reflection geometry requires a collimated beam, so a fine focus X-ray tube configuration should be used. But this requires a low take off angle ( generally 6°) which leads to strong self absorption of the low energy X-ray photons.
A high power diffraction tube was modified by integrating the tube in the vacuum circuit of the measuring chamber. The anode block was constructed to be changeable, Si was used as anode material. The anode geometry was optimized for high brilliance and low absorption.
The results show an improvement of detection limits in comparison to a standard Cr anode fine focus tube. A detection limit of 90 pg for Na has been achieved with 600 W
A NEW WINDOWLESS SI ANODE FINE FOCUS X-RAY TUBE FOR THE MORE EFFICIENT EXCITATION OF LOW Z ELEMENTS IN TXRF
No full textA NEW WINDOWLESS SI ANODE FINE FOCUS X-RAY TUBE FOR THE MORE EFFICIENT EXCITATION OF LOW Z ELEMENTS IN TXRF
Th.Meinschad1, Christina Streli1, P.Wobrauschek1, Ch. Eisenmenger-Sittner2,
1Atominstitut, Univ. of Technology, Vienna, Austria
2 Inst. of condensed matter, Vienna Univ.of Technology, Austria
To excite low Z elements efficiently low energy photons just above the absorption edge of the element to be analyzed are required. Especially to detect Al and Na on Si wafer surfaces, photons with an energy below the Si ?K edge but above the Al-K edge are needed to avoid a strong excitation of the Si bulk but giving efficient excitation of the analytes. Using synchrotron radiation is the most effective way but also for lab scale instrumentation there are some approaches. Besides W-M lines also the use of Si K line is possible. An additional problem is the fact that total reflection geometry requires a collimated beam, so a fine focus X-ray tube, electronic focus 8mm x 0.4mm configuration should be used. In the normal design a 6° take off angle is chosen, which leads to strong self absorption in the anode of the low energy X-ray photons. A compromise between high brilliance and low self absorption was made and a take off angle of 19 degree was chosen.
A commercially available high power diffraction tube was modified and integrated in the vacuum circuit of the measuring chamber. The anode was designed easily exchangable and Si was the target material. The anode geometry was optimized for high brilliance and low absorption.
An improvement of detection limits in comparison to a standard Cr anode fine focus tube could be obtained. Results are presented
A WINDOWLESS SI ANODE X-RAY TUBE WITH FINEFOCUS FOR THE EFFICIENT EXCITATION OF LOW Z ELEMENTS ON SI WAFER SURFACES WITH TXRF
No full textA WINDOWLESS SI ANODE X-RAY TUBE WITH FINEFOCUS
FOR THE EFFICIENT EXCITATION OF
LOW Z ELEMENTS ON SI WAFER SURFACES WITH TXRF
Th.Meinschad1, Christina Streli1, P.Wobrauschek1, Ch. Eisenmenger-Sittner2,
1Atominstitut, Univ. of Technology, Vienna, Austria
2 Inst. of condensed matter, Vienna Univ.of Technology, Austria
Low energy photons are required to excite low Z elements efficiently. Especially to detect Al and Na on Si wafer surfaces, photons with an energy below the Si ?K edge but above the Al-K edge are needed to avoid a strong excitation of the Si bulk but giving efficient excitation of the analytes. Using synchrotron radiation is the most effective way but also for lab scale instrumentation there are some approaches. Besides W-M lines also the use of Si K line is possible. An additional problem is the fact that total reflection geometry requires a collimated beam, so a fine focus X-ray tube, electronic focus 8mmx0.4mm configuration should be used. In the normal design a 6° take off angle is chosen, which leads to strong self absorption in the anode of the low energy X-ray photons. A compromise between high brilliance and low self absorption was made and a take off angle of 19 degree was chosen.
A commercially available high power diffraction tube was modified and integrated in the vacuum circuit of the measuring chamber. The anode was designed easily exchangable and Si was the target material. The anode geometry was optimized for high brilliance and low absorption
An improvement of detection limits in comparison to a standard Cr anode fine focus tube could be obtained. Results are presented
EP-1759: Logfile based detection and dosimetric effects of deviations between TPS and linac
No full textMedia 6: Combined acoustic and optical trapping
No full textOriginally published in Biomedical Optics Express on 01 October 2011 (boe-2-10-2859
The SPL (II) at CERN, a Superconducting 3.5 GeV H- Linac
No full textA revision of the physics needs and recent progress in the technology of superconducting (SC) RF cavities have triggered major changes in the design of a SC H-linac at CERN. With up to 5MW beam power, the SPL can be the proton driver for a next generation ISOL-type radioactive beam facility (âEURISOLâ) and/or supply protons to a neutrino () facility (conventional superbeam + beta-beam or -factory). Furthermore the SPL can replace Linac2 and the PS booster (PSB), improving significantly the beam performance in terms of brightness, intensity, and reliability for the benefit of all proton users at CERN, including LHC and its luminosity upgrade. Compared with the first conceptual design, the beam energy is almost doubled (3.5GeV instead of 2.2 GeV) while the length is reduced by 40%. At a repetition rate of 50 Hz, the linac reuses decommissioned 352.2MHz RF equipment from LEP in the low-energy part. Beyond 90MeV the RF frequency is doubled, and from 180MeV onwards high-gradient SC bulkniobium cavities accelerate the beam to its final energy of 3.5GeV. This paper presents the overall design approach, together with the technical progress since the first conceptual design in 2000
