Electron Beam to Light and Light to Electron
Electron Beam to Light and Light to Electron Beam: Come play with me! Alexander Zholents Symposium celebrating Swapan Chattopadhyay’s Retirement April 30, 2021, Fermilab 1
Come play with me! https: //controlsweb. aps. anl. gov/controls/9000_Personal/Thomas_Fors/demon/ 2
Maxwell’s demon paradox Maxwell first introduced the ‘finite being’ in a letter to his school friend Tait (dated 11 December 1867) and repeated this argument in his 1871 treatise, Theory of Heat. James Clerk Maxwell William Thomson (Lord Kelvin) coined the term Maxwell’s Demon “Second law of thermodynamics is statistical law and can’t be applied to fluctuations of individual molecules” — implied that information can be converted to energy 3
Demon’s exorcism Smoluchowski (1914), Szilard (1929), Shannon (1948), Brillouin (1953) … 4
01101000 100111001 00000000 k. BT ln(2) per bit Charles H. Bennett Discovered the fundamental law (Landauer’s principle) governing thermodynamics of information. “Irreversibility and Heat Generation in the Computing Process” (1961). Proposed a reinterpretation of Maxwell's demon, attributing its inability to break the second law to thermodynamic cost of destroying memory (1982). 5
Demon’s exorcism Demon’s inability to violate the Second Law of Thermodynamics arises from the cost of information erasure to entropy. 6
301 pages 7
Stochastic cooling Stochastic Damping of Betatron Oscillations in the ISR, CERN, 1972 Transverse pick-up Simon van der Meer s n o i t a u t c u l F Nobel Prize in 1984 shared with Carlo Rubbia "for their decisive contributions to the large project, which led to the discovery of the field particles W and Z, communicators of weak interaction. Drawing is reproduced from van der Meer’s no mixing Nobel Lecture Amplifier Transverse kicker good mixing Slice, Ns Ns 8
S. van der Meer*: “Such a system resembles Maxwell's demon, which is supposed to reduce the entropy of a gas by going through a very similar routine, violating the second law of thermodynamics in the process. ”, *) Nobel prize lecture, 1984 9
m e r o e h t e l l i v u o i L s e t a l o i V This is only one of the instances in which conclusions which we have drawn from our experience of bodies consisting of an immense number of molecules may be found not to be applicable to the more delicate observations and experiments which we may suppose made by one who can perceive and handle the individual molecules which we deal only in large masses. J. C. Maxwell, Theory of Heat (1871) Limitations of the Second Law of Thermodynamics 10
20 December 1993 Max Zolotorev Alexander Mikhailichenko “For example, the method has application to electron-positron cooling as well as potential in muon cooling. ” 11
IOTA storage ring at FERMILAB where a test of Optical Stochastic Cooling of electrons is taking place 12
OSC limitations Delay adjustment using bypass e. Light signal is Light signal produced in amplifier undulator Zolotorev, Zholents, “Transit-time method of optical stochastic cooling”, Phys. Rev. E, 1994 Amplified light signal is used in undulator to correct the offset • Amplifiers are available only for several IR wavelengths • Amplifier and refractive lenses limit bandwidth of the system 13
16 March 2009 The is a variant of stochastic cooling with a bandwidth Vladimir Litvinenko Yaroslav Derbenev Ce. C is a prime candidate for hadron cooling in EIC • Needs low emittance and low energy spread intense electron beam at a high energy 14
New approach: using short wavelength SR Zholents, Rebuffi, Shi “Stochastic cooling with EUV light”, Phys. Rev. Acc. and Beams, 2021 Wiggler No information must be acquired, and no information is needed to perform cooling Wiggler • No amplifier • Reflective optics • 100% relative bandwidth • Use multiple light sources within one setup Electron selfcorrection action 15
OSC and Ce. C follow van der Meer’s canonic approach 1. Measure 2. Correct Dz Energy beam slice length Position inside the beam e 4. Repeat 3. Randomize 16
New approach: delayed correction Measure (and hold) and do it many time before applying corrections Wiggler 1 2 34 Wiggler e- 1 2 34 1. 2. 3. 4. Correct Measure, randomize 17
NEW APPROACH: CASCADE-AMPLIFIED STOCHASTIC COOLING 1 2 3 4 When Nc cooling sections are used back-to-back, the cooling rate is growing NOT as Nc, but as 18
AN EXAMPLE OF A 300 -M CIRCUMFERENCE STORAGE RING Each 125 -m long straight contains a cooling cascade with seven cooling sections Uses 16 wiggler, each 1. 3 m long Cooling section: green line shows electron trajectory, red line shows light trajectory Parameter Value Units Beam energy Circumference Vertical emittance Horizontal emittance Rel. energy spread Bunch length Peak current Synchrotron radiation damping time Stochastic cooling damping time 150 297. 3 1. 5 9. 6 2. 0 E-04 6 0. 65 Me. V m nm nm 32 ms cm A 19
Dear Swapan, I wish you a cool retirement and no superficial demons around to bother you. 20
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