Discussion List Archives

[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 
choices for commercial systems. There are many of these that are 
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 
( 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 
distances between apertures, sample and detector. Some of the 
are not very flexible in their accomodation of customer resolution wishes 
but Dr. Siong should be fairly adamant about insisting on appropriate 

Even if Dr. Siong chooses to go with a commercial 3-pinhole SAXS system, 
is my recommendation that he should still form an opinion on which of the 
following components he would want in his setup.

Sealed tube
Rotating Anode
	high intensity

None, or
Cross-Coupled Goebel Optics (Bruker)
	High Intensity
Quasi-focusing Confocal Max Flux (Osmic)
	Even Higher intensity (X2)

Sample Environment:

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"


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