Comments on: Molecular Photography

By: Dave

Dave — Sat, 18 Nov 2006 15:48:27 +0000

AFM, as well as Scanning Tunneling Microscopy, are both good tools for atomic imaging, but both have some major constraints - the first of which is their constraint to solid substrates, and only the surface of those substrates. Also, neither technique has the ability to actually take a “picture” of the surface, but rather makes a topological map of the region based on current differences and tip deflection. I’ll never forget the first time I saw an AFM image - imagine getting a B.S. degree in Chemistry and never seeing an atom other than through X-ray crystallography!

By: Jeremy

Jeremy — Mon, 06 Nov 2006 01:44:46 +0000

Nigel Cook,

I believe they imaged beetles. In my opinion, the scientific merit behind their work is slightly clouded. They went outside the lab in the woods and gathered up whatever bugs they could find and stuck them in the beam. One of the objectives of the experiment was to see ‘how long it would take for a bug to go berserk’. But, because there are no activists protecting the rights of dung beetles, there was no problem. I think one of their images appeared on the cover of Science a few years back…

By: N. Peter Armitage

N. Peter Armitage — Sun, 05 Nov 2006 22:18:14 +0000

>I thought that shooting a cloud of molecules with a high-energy x-ray beam was >like shooting a cloud of gnats with a fire hose â€” you could get one good still >frame, but then the reaction would be blown apart. Is this one of those dealies >where you keep running the same reaction over and over, taking shots at 1ms, >2ms, 3ms…?

Aaron, you got it… ‘cept it’s more like 1 picosecond, 2 ps, 3ps!

-P

By: JoAnne

JoAnne — Sun, 05 Nov 2006 06:28:01 +0000

Hi Aaron,

I am not an expect on this, but I think perhaps the trick is that the X-ray pulses are just plain super fast, being just a nanosecond apart. Or perhaps since LCLS is at the high energy end of the X-ray spectrum, perhaps they don’t disturb the molecules that much as their wavelengths are a couple of magnitudes shorter than the molecular size. Just a couple of thoughts…

By: Aaron

Aaron — Sun, 05 Nov 2006 03:27:50 +0000

On a more serious note, how do you plan to use this new-fangled contraption for making movies? I thought that shooting a cloud of molecules with a high-energy x-ray beam was like shooting a cloud of gnats with a fire hose — you could get one good still frame, but then the reaction would be blown apart. Is this one of those dealies where you keep running the same reaction over and over, taking shots at 1ms, 2ms, 3ms…? I don’t understand how this could work well with reactions involving more than two molecules!

By: Aaron

Aaron — Sun, 05 Nov 2006 03:16:08 +0000

free electrons

Free electrons?! Where?!

By: JoAnne

JoAnne — Sat, 04 Nov 2006 07:15:26 +0000

Chris W: Wow, I have no idea. Sounds like something we should fix though. Unfortunately, I am barely beyond point & click, so I’m the wrong one to be having this conversation.

Alexey: Precision measurements and heavy flavor physics, as important as they are, were given the lowest priority on both the EPP2010 and P5 roadmaps. I believe the particle physics community is just not willing to pay $500 M for a super-B-factory. That kind of funding is not up to the SLAC director, that brand of science would have to be a priority of the community and DOE.

By: Chris W.

Chris W. — Sat, 04 Nov 2006 00:44:51 +0000

JoAnne,

Sorry to throw in a blog administration question, but why is select/copy-and-paste from CV posts disabled under Internet Explorer? (I haven’t tested Firefox or other browsers.)

To grab a paragraph for inclusion in an email, as I just did, I have to view the page source, locate the relevant paragraph in the HTML code, and copy it from my source viewer.

I believe this has been an issue ever since CV came online.

By: nigel cook

nigel cook — Fri, 03 Nov 2006 19:09:42 +0000

Jeremy, what insects did they x-ray? American cockroaches allegedly can only take 67,000 R, but German cockroaches are hardier and will take 90-105,000 R, see http://www.ipm.iastate.edu/ipm/hortnews/1996/12-13-1996/bomb.html

By: Alexey Petrov

Alexey Petrov — Fri, 03 Nov 2006 14:39:09 +0000

It’s great to hear that particle physics will be an active part of the Lab in the future, at least theory and astro… Rumor had it that the leadership of SLAC didn’t even want to consider “local” continuation of the experimental particle program in B-physics (i.e. super B-factory) — is that true?

Actually, X-ray laser is not the only technique for this. There is also a technique called “Atomic Force Microscopy” that is used for “taking pictures” of the atoms… but the device is really tabletop (located in a lab across a hall from my office)…