Talk:Free-electron laser

message: Since a "microwave amplification by stimulated emission of radiation" device is called a maser and a "light amplification by stimulated emission of radiation" device is called laser, an "X-ray amplification by stimulated emission of radiation" device should most properly be called either a xaser, or since masers were first, an X-ray maser?  Besides xaser being hard to pronounce, laser is a much more common term than maser ever was, so I imagine that it will stay "X-ray laser".
--David R. Ingham 23:28, 18 July 2005 (UTC)
replies: text: An FEL does not amplify the x-rays (or whatever kind of radiation) by stimulated emission. See self-amplified spontaneous emission (SASE). I believe FEL has the word laser in it because free electrons create laser alike radiation, i.e. monochromatic, directional (thereby intense) and coherent. FEL can produce light in various wavelength regimes. Only x-ray free electron laser are commonly abbreviated as XFEL. I've never heard 'xaser' and I think 'x-ray laser' is misleading because it is not stimulated emission that amplifies the radiation. I propose to use FEL or XFEL instead! --Maderthaner (talk) 02:17, 13 November 2014 (UTC)
thread_title:  The name of an X-ray device 

message: I have a doctorate in biophysics, yet I could not understand discussion of the XFEL. Sorry to whoever worte it. :) 
Can someone who understands the basic underlying theory rewrite this section in the style of the "News/Focus" section of the journal Science.  
An example: the current versions says "down to a wavelength of 1.5 Ångstroms." How good is that? How "hard" are x-rays of that wavelength? The journal Science says, "These 'hard' x-ray wavelengths—down to 0.1 nanometers—promise to reveal the structure of proteins that have eluded other techniques and nanometer-scale features inmeterials.",Science, vol 314 (5800), p. 751, 2006 
This is an excellent example of the style I would like to see here.
Can someone who understands the technology please describe how XFEL are built and generate x-rays? Nwbeeson 14:53, 20 November 2006 (UTC)
thread_title:   Very Dense Verbage 

message: It seems to me that the word "so" is used too many times in this paragraph, it doesn't read well.
"Depending on the position along the undulator the oscillation of an electrons is in phase or not in phase with this radiation. So the light either tries to accelerate or decelerate this electrons. So it gains or loses kinetic energy, so it moves faster or slower along the undulator. So the electrons form bunches. Now they are synchronized and will in turn emit synchronized (that is coherent) radiation."
I would recommend replacing it with something like:
"Depending on the position along the undulator the oscillation of an electrons is in phase or not in phase with this radiation. The light either tries to accelerate or decelerate this electrons. It thereby gains or loses kinetic energy, so it moves faster or slower along the undulator. This causes the electrons to form bunches. Now they are synchronized, and will in turn emit synchronized (that is coherent) radiation."
--Patrick--70.58.248.157 23:39, 8 December 2006 (UTC)
thread_title:  Last paragraph of FEL creation 

message: freakin ucsb's free electron laser 
http://sbfel3.ucsb.edu/  —Preceding unsigned comment added by 68.6.66.57 (talk) 05:03, 18 September 2007 (UTC)
thread_title:  Outside Links 

message: http://blog.wired.com/defense/2008/09/weapons-grade-l.html  —Preceding unsigned comment added by 137.244.215.19 (talk) 13:54, 25 March 2009 (UTC)
replies: text: Nothing about FEL on that page! -- Tomdo08 (talk) 20:58, 23 September 2010 (UTC)
thread_title:  Northrop Grumman hits Weapons grade FEL 

message: can you "tune" SASE FEL by slowly changing the energy of the electron beam? Or would the beam (its coherency) have to break down inbetween? because the beam is faster than the electrons, and would interact with electrons that still have the old energy. would the beam just get a bit "dimmer" while tuning? --Maxus96 (talk) 02:06, 27 March 2010 (UTC)
thread_title:  tuning / noisy startup problem 

message: The description of the workings is rather terse. It's not clear to me how the FEL is different from other undulators. JKeck (talk) 19:39, 5 May 2010 (UTC)
thread_title:  Vs. Undulator? 

message: The description of the FEL gets nearly everything wrong. I will mend this in the near future. -- Tomdo08 (talk) 21:03, 23 September 2010 (UTC)
replies: text: The description "Beam creation" is incomplete and requires verification an I agree the entire article needs work, but I wouldn't go so far as to say it is wrong. Insertion devices are indeed used in free electron laser devices. Polyamorph (talk) 20:12, 6 November 2010 (UTC)
thread_title:  Explanation wrong 

message: I'm curious what the analog to population inversion is in a FEL. 174.108.116.161 (talk) 05:28, 11 November 2010 (UTC)
thread_title:  Analog of Population Inversion? 

message: CF: http://www.foxnews.com/scitech/2011/01/20/raygun-breakthrough-revolutionize-naval-power/?test=faces 
"Military Tech: Breakthrough Laser Could Revolutionize Navy's Weaponry" Published January 20, 2011  Hope this helps, Charles Edwin Shipp (talk) 00:30, 21 January 2011 (UTC)
thread_title:  Navy FEL breakthrough 

message: Is there a reason that the article does not cite the relevant papers for things such as the history behind FELs for the introduction, but rather lists them as further reading? --Dlfreese (talk) 07:15, 31 May 2012 (UTC)
thread_title:  Sources 

message: Please someone correct that mistake, there is no stimulation, amplification essentially starts from noise! I tried to correct this already but my changes have been undone! English Wikipedia is the first search hit and wrong, great! 
Reference:
E. Saldin, E. Schneidmiller, and M. Yurkov, "The Physics of Free Electron Lasers" (Springer, 2000) (page 10 e.g.)
http://flash.desy.de/ (english, bottom paragraph)  — Preceding unsigned comment added by 130.149.239.38 (talk) 11:33, 29 May 2013 (UTC)
replies: text: I did change this. I have to say, this section of the article could be improved. --Maderthaner (talk) 02:23, 13 November 2014 (UTC)
thread_title:  SASE - Self amplified SPONTANEOUS emission   the article is wrong here 

message: I propose to restructure the beam creation part of the article. I have the feeling that the first couple sections are all talking about this but not really to the point. I noticed often that the SASE process was explained in a dubious way and also seeding/self-seeding could be brought under this section. There is also multiple ways of creation a FEL seeded beam, e.g. self-seeding.--Maderthaner (talk) 02:33, 13 November 2014 (UTC)
thread_title: Wrapping up the beam creation, large facility, mirror and seeded section

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thread_title:  External links modified 

message: a list of FEL prize awards doesn't seem appropriate for this page.  perhaps it should get its own page, or be deleted?— Preceding unsigned comment added by Pjgrandinetti (talk • contribs) 22:39, March 29, 2021 (UTC)
:I deleted it. It was unreferenced and probably not notable enough for its own page. Pelirojopajaro (talk) 07:08, 30 March 2021 (UTC)
thread_title:  FEL prize? 

message: The examples of FELs lists two devices in Japan. As far as i can gather, the SPring-8 SASE source was a project that ended up becoming SACLA, at the Spring-8 campus at RIKEN Harima Institute.
We should consider removing SPring-8 Compact SASE Source. 91.64.185.27 (talk) 06:29, 2 May 2024 (UTC)
thread_title:  SPring-8 Compact SASE Source --> SACLA at Spring8