<html dir="ltr"> <head> <meta http-equiv="Content-Type" content="text/html; charset=Windows-1252"> <style id="owaParaStyle">P { MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px } </style> </head> <body dir="ltr" style="WORD-WRAP: break-word" fPStyle="1" ocsi="0"> <div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;"> <p>Hi, Kirk.</p> <p> Very interesting! Note that the spreading out in time of the resulting photons doesn't matter</p> <p>if the initial source is CW, on all the time.</p> <p> This reminds me some aspects of my recent proposal called N-Ring CircUS; namely, the muons</p> <p>make multiple passes before finally finding their way out of the ring via a septum. And since the</p> <p>source is CW, it doesn't matter that it takes time to get out.</p> <p> Another way to say it is that, for a 100% duty cycle situation, only 5D of the 6D phase space</p> <p>matters.</p> <p> I've attached a brief summary of the N-Ring CircUS idea.</p> <p>--Chuck</p> <div style="FONT-SIZE: 16px; COLOR: #000000; FONT-FAMILY: Times New Roman"> <hr tabindex="-1"> <div id="divRpF634649" style="DIRECTION: ltr"><font face="Tahoma" color="#000000" size="2"><b>From:</b> map-l-bounces@lists.bnl.gov [map-l-bounces@lists.bnl.gov] on behalf of Kirk T McDonald [kirkmcd@Princeton.EDU]<br> <b>Sent:</b> Wednesday, December 19, 2012 10:36 PM<br> <b>To:</b> Kirk McDonald<br> <b>Cc:</b> MAP-l@lists.bnl.gov<br> <b>Subject:</b> [MAP] Light recycling; Piccione lip<br> </font><br> </div> <div></div> <div> <div dir="ltr"> <div style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: 'Arial'"> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">Folks,</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">I have become fortuitously aware of an old trick in the lamp industry that is now sometimes called “light recycling” – with the goal of enhancing the optical brightness of light sources.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">Remember, brightness = power / area in transverse phase space</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">(although the opticians don’t generally say it this way, perhaps using the buzzword “etendue” instead of “area in transverse phase space”)<br> </font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">In our project, we try to increase the brightness by “cooling”/shrinking the area in transverse phase space.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">The opticians’ trick is to “recycle” the light so that one photon gets counted many times in the same area in phase space, effectively increasing the power, while leave the emittance the same.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">The historical way of doing this (dating back at least to 1936) involves a cylindrical cavity lined with a phosphor (i.e., a fluorescent lamp) with a small slit in the phosphor to let light out.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">A photon has only a small probability P to escape out the slit directly after being emitted by the phosphor.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">Generally, the photon hits another region of the phosphor, is absorbed, and then re-emitted.  [The cavity can be lined with a reflector to assist in this process.]</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">On average, the photon bounces around N = 1 / P times before it escapes through the slit.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">Hence, the steady-state emission of photons by the phosphor surface is N times greater than if the photons flew away on their first emission – as holds for an ordinary fluorescent lamp.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">The net effect is that the light coming out of the slit is N times brighter than the light from an ordinary fluorescent bulb of the same output power.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">The brightness has been enhanced N-fold (with no emittance reduction) to the extent that the absorption and re-emission involves no losses.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">[I think the lamps in Xerox machines and scanners are of this type.]</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">I’ve written up a pedagogic note on this:</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <a title="http://puhep1.princeton.edu/~mcdonald/examples/lamp.pdf" href="http://puhep1.princeton.edu/~mcdonald/examples/lamp.pdf" target="_blank">http://puhep1.princeton.edu/~mcdonald/examples/lamp.pdf</a></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><font size="2">--------------------------------------</font></font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><font size="2">This trick seems different from what we do to enhance the brightness of particle beams.</font></font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><font size="2"></font></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><font size="2">However, a comment by Fred Mills, dated 9/98, near the bottom of my web page</font></font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><a title="http://puhep1.princeton.edu/~mcdonald/mumu/physics/" href="http://puhep1.princeton.edu/~mcdonald/mumu/physics/" target="_blank">http://puhep1.princeton.edu/~mcdonald/mumu/physics/</a></font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial"><font size="2">has me wondering if part of the effect of the “Piccione lip” seen on p. 4 of</font></font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <a title="http://puhep1.princeton.edu/~mcdonald/mumu/physics/lichtenberg_mura-110.pdf" href="http://puhep1.princeton.edu/~mcdonald/mumu/physics/lichtenberg_mura-110.pdf" target="_blank">http://puhep1.princeton.edu/~mcdonald/mumu/physics/lichtenberg_mura-110.pdf</a><font face="Arial" size="2"> </font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">was to use multiple scattering in the “lip” to kick some particles into a desired area of phase space.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">That is, perhaps we can say that ionization cooling also includes a small effect equivalent to the opticians’ trick of “light recycling”.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">What do you think?</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">--Kirk</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">PS  The opticians are after big game = use of such tricks to make better solar energy concentrators for photovoltaic energy generation (or even just heating water).</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">In the past, such efforts have not involved brightness enhancement, but only clever rearrangement of light in phase space (as in Winston cones).</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">The next generation of brightness enhancement schemes uses materials with differing absorption and emission spectra to play additional “tricks”.   New engineered optical materials, called photonic band gap materials, could play a key role here.</font></div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2"></font> </div> </div> <div> <div style="DISPLAY: inline; FONT-WEIGHT: normal; FONT-SIZE: small; COLOR: #000000; FONT-STYLE: normal; FONT-FAMILY: 'Calibri'; TEXT-DECORATION: none"> <font face="Arial" size="2">If these solar brightness-enhancement schemes pay off, they will be able to fund all of high energy physics....</font></div> </div> </div> </div> </div> </div> </div> </body> </html>