[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: SAXS advice for Malaysian National U.
- Subject: Re: SAXS advice for Malaysian National U.
- From: "John D. Barnes" <john.barnes@nist.gov>
- Date: Tue, 7 Nov 2000 11:40:14 -0500
Sender: karsten dan joensen <joensen@osmic.com> Subject: Re: SAXS advice for Malaysian National U. Dear John As a member of the commercial X-ray community I would suggest that before making his own instrument Dr. Kan Chee Siong should consider some of other choices for commercial systems. There are many of these that are preferable over the Bruker GADDS system depending on his specific needs in terms of intensity, resolution, and/or background reduction. Firs Dr. Siong should consider if he is going to measure oriented samples. ( I wouldn't expect his fluids to be oriented). If he is NOT going to measure oriented samples: he should definitely consider looking into a new 1-dimensional SAXS camera presently undergoing final testing at the lab of Prof. Glatter in Graz, Austria in collaboration with Anton Paar Company. This system has a very high intensity (roughly 40 times the existing Kratky Systems) and a very good resolution due to focusing optics and a clever use of the slits. Finally, some very nice data-reduction and interpretation software has been developed for this system. If he IS going to measure oriented samples: I can only recommend a traditional 3-pinhole SAXS system. Such commercial systems are available from Rigaku, and Bruker (Bruker prefers 2-pinhole systems). However I am aware that also Nonius, Seifert and Osmic have constructed such systems for their customers. For a 3-pinhole SAXS system Dr. Siong will need to decide what resolution he is looking for in most of his samples. This will determine the required distances between apertures, sample and detector. Some of the manufacturers are not very flexible in their accomodation of customer resolution wishes but Dr. Siong should be fairly adamant about insisting on appropriate resolutions. Even if Dr. Siong chooses to go with a commercial 3-pinhole SAXS system, it is my recommendation that he should still form an opinion on which of the following components he would want in his setup. Source: Sealed tube stable Rotating Anode high intensity Optics: None, or Graphite Monochromatic Cross-Coupled Goebel Optics (Bruker) Monochromatic High Intensity Quasi-focusing Confocal Max Flux (Osmic) Monochromatic Even Higher intensity (X2) Sample Environment: Detector: Gas Detector (Bruker's HiStar) High Efficiency Moderate Spacial Resolution (0.2mm -0.8 mm) Continuous Readout High count-rate saturation Image plate Moderate Efficiency High Spatial Resolution Read-out only after measurement High Count rate capability I hope this is helpful in constructing your "official reply" Sincerely Karsten Dan Joensen Dr. John D. Barnes email: john.barnes@nist.gov Natl Inst of Stds and Tech Voice: 301-975-6786 100 Bureau Drive, Stop 8544 FAX: 301-975-4977 Gaithersburg, MD 20899 URL: http://www.nist.gov/sas
- Prev by Date: SAXS advice for Malaysian National U.
- Next by Date: Passing of Harry Brumberger
- Prev by thread: SAXS advice for Malaysian National U.
- Next by thread: In-House X-Ray Equipment
- Index(es):