Source
string
Question
string
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expert_annotation
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int64
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
In fact, with a full control over amplitude and phase seen by the particles the question becomes how to best optimize the drive pulse. At this purpose, it is envisioned adopting machine learning algorithms to optimize the 2D mask which gets applied to the laser drive pulse by the liquid crystal modulator [48]. 5 DLA Un...
4
Yes
1
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
Looking towards applications of dielectric laser acceleration, electron diffraction and the generation of light with particular properties are the most catching items, besides the omnipresent goal of creating a TeV collider for elementary particle physics. As such we will look into DLA-type laser driven undulators, whi...
4
Yes
1
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
4.2 Soft tuning of DLA parameters 11 5 DLA Undulator 13 5.1 Tilted Grating Design 13 5.2 Analytical Model for the Non-Synchronous Undulator 14 5.3 Simulation of the Beam Dynamics in Tilted Gratings 16 6 Conclusion 18 1 Introduction The combination of periodic dielectric structures and coherent light allows to reverse t...
1
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
There have been two major approaches to producing injectors of sufficiently high brightness. The first approach uses a nanotip cold field or Schottky emitter in an electron microscope column that has been modified for laser access to the cathode [14, 21, 22]. One can then leverage the decades of development that have b...
5
Yes
1
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ where $m _ { 0 } c ^ { 2 } / q = 5 1 1 \\mathrm { \\ k V }$ is the rest energy equivalent and $\\phi$ is the phase within one DLA cell. Analyzing the solutions of the equation for transverse motion into a slowly varying secular component and a fast oscillation, we can rewrite for the slow drift motion $$ { \\frac { ...
1
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
2 Ultra-low Emittance Injector The sub- $4 0 0 \\\\mathrm { n m }$ wide accelerator channel and field non-uniformity in dielectric laser accelerators place very strict emittance requirements on the electron injector. Typical acceptances in an APF DLA designed for a 2 micron drive laser require a ${ \\\\sim } 1 0 ~ \\\\...
5
Yes
1
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
Key to the high gradients in DLA is the synchronization of optical near fields to relativistic electrons, expressed by the Wideroe condition $$ \\lambda _ { g } = m \\beta \\lambda $$ where $\\lambda _ { g }$ is the grating period, $\\lambda$ is the laser wavelength, and $\\beta = \\nu / c$ is the the electron velocity...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ \\lambda _ { \\mathrm { { p } } } = \\frac { \\lambda _ { \\mathrm { { u } } } } { 2 { \\gamma _ { 0 } } ^ { 2 } } \\left( 1 + \\frac { { K _ { \\mathrm { { z } } } } ^ { 2 } } { 2 } \\right) \\approx 9 ~ \\mathrm { { n m } , } $$ corresponding to soft $\\boldsymbol { \\mathrm { X } }$ -rays with $E _ { \\mathrm { p...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
4.2 Soft tuning of DLA parameters The original plan proposed to hard-wire spatial harmonics into the structure to obtain the ponderomotive focusing effect. In practice, one can also simply modulate the drive laser phase, effectively introducing spatial harmonics into a generic, strictly periodic grating, see Fig. 8. Th...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ where $E _ { z }$ is the longitudinal component of the electric field at the laser center frequency in the channel. Often, $E _ { z }$ is normalized to the amplitude of the incident laser field. The transverse dependence of $\\boldsymbol { e } _ { 1 }$ allows also to calculate the the transverse kicks by means of th...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ The first term recovers the tracking equation of DLATrack6D (see ref. [9]). The correction terms contribute less than $1 \\%$ for the investigated structures. Figure 14 a) compares tracking results for the particle at the beam center of a synchronous and a non-synchronous DLA undulator. In the synchronous undulator ...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
k _ { x } ^ { 2 } + k _ { y } ^ { 2 } = - \\frac { \\omega ^ { 2 } } { \\beta ^ { 2 } \\gamma ^ { 2 } c ^ { 2 } } , $$ where $\\omega = 2 \\pi c / \\lambda$ is the laser angular frequency and $\\beta , \\gamma$ are the relativistic velocity and mass factors. Note that the longitudinal field Eq. 3.1 suffices to describe...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ \\\\mathbf { a } \\\\left( x , y , z , c t \\\\right) = a _ { \\\\mathrm { z } } \\\\cosh \\\\left( k _ { \\\\mathrm { y } } y \\\\right) \\\\sin \\\\left( k c t - k _ { \\\\mathrm { z } } z + k _ { \\\\mathrm { x } } x \\\\right) \\\\mathbf { e } _ { \\\\mathrm { z } } $$ with the reciprocal grating vectors of the ...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ k _ { \\mathrm { u } } \\approx \\frac { 1 } { \\beta } k - k _ { \\mathrm { z } } . $$ The analytical model provides design guidelines for the experimental realization of an DLA undulator. In Eq. (5.4) the deviation of $k$ with respect to a synchronous DLA structure determines the undulator wavelength $\\lambda _ {...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
Moving forward, there are possibilities of increasing the acceleration gradients in DC biased electron sources through the use of novel electrode materials and preparation [25, 27] to 20 to 70 $\\mathbf { k V / m m }$ or greater gradients. These higher gradients, combined with the local field enhancement at a nanotip e...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
3 Alternating Phase Focusing DLA 3.1 Principle and Nanophotonic Structures The advantage of high gradient in DLA comes with the drawback of non-uniform driving optical nearfields across the beam channel. The electron beam, which usually fills the entire channel, is therefore defocused. The defocusing is resonant, i.e. ...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
Logan Su, Rahul Trivedi, Yu Miao, Olav Solgaard, Robert L Byer, and Jelena Vuckovic. On-chip integrated laser-driven particle accelerator. Science, 367(January):79–83, 2020. [46] D. Cesar, J. Maxson, P. Musumeci, X. Shen, R. J. England, and K. P. Wootton. Optical design for increased interaction length in a high grad...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
$$ K _ { \\mathrm { z } } = a _ { \\mathrm { z } } { \\frac { k _ { \\mathrm { x } } } { k _ { \\mathrm { u } } } } = { \\frac { q } { m _ { 0 } c ^ { 2 } } } { \\frac { k _ { \\mathrm { z } } } { k k _ { \\mathrm { u } } } } \\left| e _ { 1 } \\left( \\alpha \\right) \\right| \\tan \\alpha \\ . $$ Figure $1 3 \\mathrm...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
Different types of DLA structures (single cells) are described in Fig. 2 for low energy (subrelativistic) and in Fig. 6 for high energy (relativistic). The usual materials are silicon or fused silica $( \\\\mathrm { S i O } _ { 2 } )$ , which can be nanofabricated by established techniques from the semiconductor indust...
augmentation
Yes
0
expert
According to the beam requirements for a typical DLA, is an electron source with 5 mm emittance suitable?
No, the aperture is sub-400nm
reasoning
Beam_Dynamics_in_Dielectric_Laser_Acceleration.pdf
6 Conclusion For the study of beam dynamics in DLA, computer simulations will remain essential. With combined numerical and experimental approaches, the challenges of higher initial brightness and brightness preservation along the beamline can be tackled. The electron sources available from electron microscopy technolo...
augmentation
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
Another component of the gas detector system developed by DESY and used at various facilities, including SwissFEL, is the huge aperture open multiplier (HAMP), which is a large multiplier used for single-shot relative flux measurements that are not an absolute evaluation of the pulse energy. The response of this device...
2
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
The HAMPs, in contrast, need characterization to evaluate their range of linearity under an applied gain voltage. This voltage needs to be regulated through an overwatch program so that the HAMP detector signals remain linear, while also being high enough to provide a good signal-to-noise ratio on its analog-to-digital...
5
Yes
1
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
File Name:[FELFastPulseEnergy]_JSR_30(2023).pdf Online absolute calibration of fast FEL pulse energy measurements Received 29 November 2022 Accepted 7 February 2023 Edited by Y. Amemiya, University of Tokyo, Japan Keywords: free-electron lasers; FELs; shot-to-shot absolute flux measurements. Pavle Juranic´,\\* Arturo ...
4
Yes
1
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
If the repetition rate of the FEL changes, the rolling buffer size is recalculated to accommodate the larger number of points in the chosen time period, and the buffer itself is reset. However, the constant $C$ remains unchanged unless the photon energy or the HAMP gain voltage change. The data buffer and single-shot p...
2
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
The method and algorithm described here have been shown to work at SwissFEL with its repetition rate of up to $1 0 0 \\mathrm { H z }$ . The optimization of the algorithm to process the data has been shown to be $1 0 0 \\%$ reliable even at the maximum $1 0 0 \\mathrm { H z }$ repetition rate, has no skipped points and...
4
Yes
1
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
This manuscript describes the developments in hardware characterization, feedback and monitoring programs, and processing algorithms that allow the photon pulse energy monitor (PBIG) at SwissFEL to deliver absolute pulse energy evaluations on a shot-to-shot basis (Juranic´ et al., 2018). The PBIG is the renamed DESY-d...
augmentation
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
2.2. Algorithm for data-processing The core of the data processing and evaluation of the absolute pulse energy on a shot-to-shot basis is the evaluation of the ratio between the slow signals and the fast signals. The slow absolute evaluation from the XGMD has an integration time of about $1 0 { \\mathrm { ~ s } } .$ , ...
augmentation
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
$$ where $I _ { \\mathrm { X G M D } }$ and ${ \\cal I } _ { \\mathrm { H A M P } }$ are the evaluations of the XGMD and HAMP signal data in the buffer, respectively. This constant is then used in further evaluations. A weighted average algorithm is used to evaluate the current conversion constant so that $$ C = W C _ ...
augmentation
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
3. Results and discussion The resulting evaluation of the absolute single-shot pulse energy matches both the absolute numbers measured by the XGMDs, and shows the shot-to-shot fluctuations of their amplitudes, as seen in Fig. 3. The fast measurement comparison was made under conditions that kept the HAMP gain voltage c...
augmentation
Yes
0
Expert
At what signal voltage is the gas detector pulse energy signal no longer in the linear range?
If the peak of the signal is higher than about 0.8 Volts.
Fact
[FELFastPulseEnergy]_JSR_30(2023).pdf
Though the setup described is fast, an even better setup would be one where the evaluation of the pulse energy would depend completely on values measured from the HAMPs, their gain voltage and a photon energy. This is theoretically possible, but would require a long-term project to gather sufficient data to correlate t...
augmentation
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
$$ Figure 6 compares the dipole and quadrupole wakes obtained by convolving with the actual bunch distribution \in SHINE and the analytical results verified with the simulated results from the ECHO2D code [22]. Assuming that the beam is close to (and nearly on) the axis, there is good agreement between the numerical an...
1
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
The $\\beta$ functions for both models are plotted in Fig. 9. In [28], the emittance growth caused by the quadrupole wakefield is fully compensated only if $\\beta _ { x } = \\beta _ { y }$ . In practice, however, the beta functions always fluctuate, and the beam suffers from the residual quadrupole wakefield. For a pe...
1
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
$$ where $k _ { \\mathrm { q } } ( s )$ is the effective quadrupole strength, which changes with $s$ within the bunch length $l$ . For the case where the beam is near the axis, a short uniformly distributed bunch was deduced \in Ref. [25] to calculate the emittance growth after passing through the dechirper. As mention...
1
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
$$ where $f ( q ) = n / d$ , and with $$ \\begin{array} { l } { n = q [ \\cosh [ q ( 2 a - y - y _ { 0 } ) ] - 2 \\cosh [ q ( y - y _ { 0 } ) ] } \\\\ { \\qquad + \\cosh [ q ( 2 a + y + y _ { 0 } ) ] ] } \\\\ { \\qquad - i k \\zeta [ \\sinh [ q ( 2 a - y - y _ { 0 } ) ] + \\sinh [ q ( 2 a + y + y _ { 0 } ) ] ] , } \\en...
1
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
The effect of a high group velocity in the radiation pulse also merits discussion. At the end of the structure length, the pulse length can be expressed [1] as $l _ { \\mathrm { p } } = 2 h t L / a p$ . For the structural parameters of SHINE, we have $l _ { \\mathrm { p } } = 5 \\mathrm { m }$ which is much longer than...
1
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
$$ Expanding the surface impedance $\\zeta ~ [ 1 8 ]$ in the first two orders, the short-range vertical dipole and quadrupole wakes near the axis are given by [19] $$ \\begin{array} { r l } & { w _ { y \\mathrm { d } } \\approx \\displaystyle \\frac { Z _ { 0 } \\mathrm { c } \\pi ^ { 3 } } { 6 4 a ^ { 4 } } { \\mathit...
augmentation
Yes
0
expert
Describe the SHINE dechirper
Flat, corrugated, metallic plates separated by an adjustable gap
Summary
Beam_performance_of_the_SHINE_dechirper.pdf
We next simply consider the quadrupole wake, where the beam is on-axis $( \\mathrm { y } _ { \\mathrm { c } } = 0 )$ . The transfer matrices for the focusing and defocusing quadrupole are given in Eq. (16), where $L$ is the length of the corrugated structure [25]. $$ \\begin{array} { r } { \\boldsymbol { R } _ { \\math...
augmentation
Yes
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where $$ F \\left( \\xi \\right) = \\int _ { - \\infty } ^ { \\xi } A ^ { \\prime } { } ^ { 2 } ( \\xi ^ { \\prime } ) d \\xi ^ { \\prime } , $$ $$ G \\left( \\xi \\right) = \\int _ { - \\infty } ^ { \\xi } A ( \\xi ^ { \\prime } ) A ^ { \\prime 2 } ( \\xi ^ { \\prime } ) d \\xi ^ { \\prime } , $$ $$ H \\left( \\xi ...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
\\begin{array} { c l c r } { \\bar { x } , \\bar { y } = x , y } \\\\ { \\bar { p } _ { x , y } = \\displaystyle \\frac { P _ { x , y } } { \\bar { P } _ { s } } = \\displaystyle \\frac { p _ { x , y } P _ { s } } { \\bar { P } _ { s } } = \\displaystyle \\frac { p _ { x , y } } { 1 + \\delta } , } \\\\ { \\bar { p } _...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ \\epsilon _ { x } = C _ { q } \\gamma ^ { 2 } \\frac { I _ { 5 } } { I _ { 2 } - I _ { 4 } } $$ with 𝑒𝑄 $C _ { q } = { \\frac { 5 5 } { 3 2 { \\sqrt { 3 } } } } { \\frac { \\hbar } { m c } } \\approx 3 . 8 3 2 \\times 1 0 ^ { - 1 3 } \\mathrm { { m } }$ and $$ \\left\\{ \\begin{array} { l l } { \\displaystyle ...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where the dependency on $\\widehat { \\tau }$ of $Q _ { s } ( \\widehat { \\tau } )$ has been introduced. The rightmost integral is given by $$ \\begin{array} { r l } & { \\frac { 1 } { | \\alpha _ { x y } | } \\displaystyle \\int _ { 0 } ^ { \\infty } d J _ { y } f _ { y } ( J _ { y } ) \\delta \\left( J _ { y } - ...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where $\\mathcal { K } _ { m }$ consists of homogeneous polynomials in $p$ and $q$ of $( m + 2 )$ degree $$ \\begin{array} { r l } & { \\mathcal { K } _ { 0 } = C _ { 2 , 0 } p ^ { 2 } + C _ { 1 , 1 } p q + C _ { 0 , 2 } q ^ { 2 } , } \\\\ & { \\mathcal { K } _ { 1 } = C _ { 3 , 0 } p ^ { 3 } + C _ { 2 , 1 } p ^ { 2...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ From Eqs. (3) and (4), it can be further observed that if $\\gamma \\sigma _ { z }$ is extremely large (i.e., $\\gamma \\sigma _ { z } \\infty ,$ ), the term ${ E } _ { s z }$ goes to zero, and Eq. (1) reduces to $$ \\begin{array} { c } { { \\phi \\approx \\displaystyle \\frac { 1 } { 4 \\pi \\varepsilon _ { 0 } } ...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where the factors $E _ { 1 }$ and $E _ { 2 }$ are given by: $$ \\begin{array} { c } { { E _ { 1 } = \\displaystyle \\frac { H _ { e } } { a } c o s ( \\theta ) - \\displaystyle \\frac { K _ { a n } } { M _ { s a t } \\mu _ { 0 } a } s i n ^ { 2 } ( \\psi - \\theta ) } } \\\\ { { E _ { 2 } = \\displaystyle \\ \\frac ...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
For a charged particle moving at a constant high $\\beta$ velocity, or being accelerated along its predominant $\\beta$ vector component, the magnetic and acceleration-dependent terms for an observer on-axis with $\\beta$ (i.e. in the direction of $\\mathbf { n }$ ) go to zero, and the electric field reduces as $$ \\be...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where we have split the transformed phase space coordinates $$ u _ { k } = \\mathcal { M } _ { k } ( x ) $$ into orthogonal axes $u _ { k _ { \\parallel } } \\in \\mathbb { R } ^ { M }$ and $u _ { k _ { \\perp } } \\in \\mathbb { R } ^ { N - M }$ . In the absence of many views, various distributions may fit the data...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where $E _ { z 0 } ( z ) \\equiv E _ { z } ( z , r = 0 )$ and similarly for $B _ { z 0 }$ . Then $$ \\frac { 2 } { r } F _ { \\perp } + F _ { z } ^ { \\prime } = - \\frac { \\beta _ { z } ^ { \\prime } } { \\beta _ { z } } \\frac { E _ { z 0 } } { \\beta _ { z } c } . $$ We can clean up the expression for $\\widetil...
augmentation
NO
0
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ where $q _ { 1 } = \\sqrt { q ^ { 2 } + \\hat { \\nu } k ^ { 2 } }$ and $n = 2$ in region $I I$ and $n = 3$ in region $I I I$ , and in region $I V$ $$ \\left( \\begin{array} { c c } { { \\bar { E } _ { z } } } & { { \\bar { H } _ { z } } } \\\\ { { \\tilde { E } _ { x } } } & { { \\tilde { H } _ { x } } } \\end{arra...
augmentation
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
File Name:Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf Alternating-Phase Focusing for Dielectric-Laser Acceleration Uwe Niedermayer,1,\\* Thilo Egenolf,1 Oliver Boine-Frankenheim,1,3 and Peter Hommelhoff2 1Technische Universit√§t Darmstadt, Schlossgartenstrasse 8, D-64289 Darmstadt, Germany $^ 2$ De...
4
NO
1
IPAC
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ \\phi _ { i + 2 } = - \\frac { 1 } { 1 + h x } \\left( \\partial _ { x } \\left( ( 1 + h x ) \\partial _ { x } \\phi _ { i } \\right) + \\partial _ { s } \\left( \\frac { 1 } { 1 + h x } \\partial _ { s } \\phi _ { i } \\right) \\right) . $$ From this recurrence relation, only two initial functions can be independen...
1
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
Earnshaw’s theorem dictates that constant focusing cannot be achieved in all three spatial directions simultaneously [29]. Thus, at least two focusing directions have to be alternating. In conventional Alvarez linacs or in synchrotrons constant focusing is applied in the longitudinal direction and alternating quadrup...
5
NO
1
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
In this Letter we solve this outstanding problem with a laser-based scheme which allows transport and acceleration of electrons in dielectric nanostructures over arbitrary lengths. It is applicable to changing DLA period lengths, which is required to accelerate subrelativistic electrons. Moreover, we find the maximum t...
1
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ \\begin{array} { l } { { V ( x , y , s = s _ { f 1 } + \\Delta s ) = - V ( x , y , s = s _ { f 2 } + \\Delta s ) } } \\\\ { { \\displaystyle ~ = \\frac { q | e _ { 1 } | \\lambda _ { g } } { 2 \\pi } \\left[ \\frac { 1 } { 2 } \\left( \\frac { \\omega y } { \\beta \\gamma c } \\right) ^ { 2 } - \\frac { 1 } { 2 } \\...
augmentation
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ L ^ { f } = \\sum _ { n = 1 } ^ { p } \\lambda _ { g } ^ { ( n ) } , \\qquad L ^ { d } = \\sum _ { n = p + 1 } ^ { 2 p } \\lambda _ { g } ^ { ( n ) } , $$ $$ l ^ { f } = ( 2 \\pi - \\varphi _ { s } ^ { ( p ) } ) \\lambda _ { g } ^ { ( p ) } / \\pi , ~ l ^ { d } = ( \\pi - \\varphi _ { s } ^ { ( 2 p ) } ) \\lambda _ ...
augmentation
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ \\varepsilon ( y , y ^ { \\prime } ) = \\hat { \\gamma } y ^ { 2 } + 2 \\hat { \\alpha } y y ^ { \\prime } + \\hat { \\beta } y ^ { \\prime 2 } , $$ $$ \\varepsilon _ { L } ( \\Delta s , \\Delta s ^ { \\prime } ) = \\hat { \\gamma } _ { L } \\Delta s ^ { 2 } + 2 \\hat { \\alpha } _ { L } \\Delta s \\Delta s ^ { \\pr...
augmentation
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
\\*niedermayer@temf.tu-darmstadt.de [1] K. Shimoda, Appl. Opt. 1, 33 (1962). [2] A. Lohmann, IBM Technical Note 5, 169, 1962. [3] R. J. England et al., Rev. Mod. Phys. 86, 1337 (2014). [4] E. A. Peralta, K. Soong, R. J. England, E. R. Colby, Z. Wu, B. Montazeri, C. McGuinness, J. McNeur, K. J. Leedle, D. Walz, E. B. So...
augmentation
NO
0
expert
Explain the Earnshaw’s theorem
At least two focusing directions have to be alternating.
definition
Alternating-Phase_Focusing_for_Dielectric-Laser_Acceleration.pdf
$$ a ( z ) = \\sqrt { \\hat { \\beta } ( z ) \\frac { \\varepsilon _ { 0 } \\beta _ { 0 } \\gamma _ { 0 } } { \\beta ( z ) \\gamma ( z ) } } , $$ where the 0 indices denote initial values. Acceleration from $8 3 \\mathrm { k e V }$ to $1 \\mathrm { M e V }$ at $\\varphi _ { 0 } = 4 \\pi / 3$ , with an average gradient ...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
One approach for addressing the issue posed by SBBU is through the introduction of an external magnetic lattice to correct for deviations in the beam trajectory due to wakefield effects. This approach is limited however in it’s maximum allowable accelerating gradient due to the fact that longitudinal wakefields scale...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
$$ SIMULATIONS RESULTS Simulations are performed using QuickPIC [8], a 3-D quasi-static PIC code, with the simulation parameters specified in Table ??. The ellipticities were calculated from the transverse cross section of the blowout cavity by taking the gradient of the density above a specific threshold, which is typ...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
This beam, with $\\sigma _ { z } = 9 5 \\mu \\mathrm { m }$ , is numerically injected into a $n _ { 0 } = 1 0 ^ { 1 3 } \\mathrm { c m } ^ { - 3 }$ plasma, yielding the condition with $k _ { p } \\sigma _ { z } \\simeq$ 2. The head of the beam is decelerated while the tail is accelerated, thus producing the desired dis...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
BEAM TRANSPORT An electric discharge-based capillary plasma source is being built at UCLA [5]. The $8 \\mathrm { c m }$ long capillary is created by boring a $4 \\mathrm { m m }$ wide opening inside a macor structure with a single channel gas supply tube. The plasma density inside this capillary has been measured to be...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
$$ \\sigma ^ { * 2 } = \\epsilon \\beta ^ { * } ( 1 + \\xi ^ { 2 } \\delta _ { p } ^ { 2 } ) , $$ where $\\epsilon$ is the beam emittance, $\\beta ^ { * }$ is the beta-function at the IP, $\\delta _ { p }$ is the relative momentum spread of the beam and $\\xi$ is the chromaticity at the IP. SYNCHROTRON RADIATION IN THE...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
The physical solution of the quadratic equation is: $$ \\begin{array} { c } { { D _ { x } = \\displaystyle \\frac { ( S + 5 \\sqrt { \\epsilon _ { i n j } \\beta _ { x } } ) \\Delta } { \\Delta ^ { 2 } - 2 5 \\delta _ { c i r } ^ { 2 } } + } } \\\\ { { \\displaystyle \\frac { 5 \\sqrt { \\epsilon _ { c i r } \\beta _ {...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
$$ 2 \\pi f \\Delta \\tau \\ll 1 , $$ where $f$ is the characteristic frequency of the wake, and $\\Delta \\tau$ is the distance between the rings. For the PETRA wake, dom inated by the resistive wall e!ects, a choice of $n _ { r } = 9$ works reasonably well. Figure 2 shows the radial discretization. NUMERICAL SIMULATI...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Table: Caption: Table 1: Beam Parameters at the Exit of the S-band Injector. Body: <html><body><table><tr><td>Injector exit parameters</td><td>Witness</td><td>Driver</td></tr><tr><td>Charge (pC)</td><td>30</td><td>200</td></tr><tr><td>Rms spot size (μm)</td><td>118</td><td>127</td></tr><tr><td>Rms length (fs)</td><td...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Table: Caption: Table 1: Comparison of Beam Dynamics for Three Different Input Distributions after Optimisation Body: <html><body><table><tr><td rowspan="2">Parameter</td><td colspan="3">Distributions</td></tr><tr><td>A</td><td>B</td><td>C</td></tr><tr><td>Emittance,εx (mm mrad)</td><td>6.19</td><td>5.21</td><td>5.00...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
In the following simulation study, we will first evaluate the effect of horizontal impedance (dipole $^ +$ detuning) and then will take into account the vertical one. EFFECT OF HORIZONTAL IMPEDANCE The horizontal beam-beam cross-wake function has been given in Eq. (12) of Ref. [14], $$ W _ { x } ^ { ( - ) } ( z ) = - \...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
$$ \\begin{array} { r } { \\beta _ { x } = \\sqrt { ( 1 + \\alpha _ { p } ^ { 2 } ) \\gamma } k _ { p } ^ { - 1 } } \\\\ { \\beta _ { y } = \\sqrt { \\displaystyle \\frac { ( 1 + \\alpha _ { p } ^ { 2 } ) \\gamma } { \\alpha _ { p } ^ { 2 } } } k _ { p } ^ { - 1 } , } \\end{array} $$ where, $\\gamma$ is the Lorentz fac...
augmentation
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Table: Caption: Table 1: Beam and DLW Parameters for DWA Experiments Body: <html><body><table><tr><td>Parameter</td><td></td></tr><tr><td>Beam Momentum</td><td>35.5MeV/c</td></tr><tr><td>Total Charge</td><td>85-100 pC</td></tr><tr><td>Normalised Emittance</td><td>~5 mm mrad</td></tr><tr><td>RMSBeamSizeatDLW</td><td>~1...
1
NO
0
expert
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
In the misaligned case [Fig. 2(b)], on the contrary, the centroid is clearly deflected, with increasing displacement along the bunch. Figure 2(d) shows that the centroid position and the running sum follow the same trend along the bunch. This confirms the expectation that the amplitude of the transverse wakefields (and...
1
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Two DLW geometries are under active consideration, circular/cylindrical and planar/slab DLWs. Strong transverse fields are excited off-axis in both geometries, leading to beam breakup instability induced by small initial offsets [4]. A method for compensating this instability is required before applications of DWA can ...
1
NO
0
IPAC
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
$$ \\begin{array} { r } { \\left[ ( 1 + \\nu _ { z } ) \\vec { W } _ { \\perp } - \\nu _ { z } \\vec { E } _ { i \\perp } + ( 1 - \\nu _ { z } ) \\vec { E _ { b \\perp } } \\right] \\Big | _ { \\partial \\Omega } = 0 , } \\end{array} $$ where $\\vec { \\pmb { W } } _ { \\perp }$ is the transverse plasma wake field and ...
1
NO
0
expert
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Figure 4 shows the position of the centroid at $t = 3 . 6$ ps (a), 4.1 ps (b), and 4.6 ps (c) behind the front of the bunch as a function of $n _ { P E }$ , for three misalignment distances (see Legend). The displacement, which is due to the effect of the dielectric wakefields, decreases when increasing $n _ { P E }$ b...
5
NO
1
expert
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
Thus, when a bunch travels with transverse offset $( x , y )$ , parallel to its axis, it drives transverse dipolar wakefields along the bunch described by [16]: $\\begin{array} { r } { W _ { \\perp } ( t ) = w ( x , y ) \\int _ { 0 } ^ { t } n _ { b } ( t ) d t } \\end{array}$ , where the bunch front is at $t = 0$ . Th...
augmentation
NO
0
expert
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
The dielectric capillary has radius $R _ { c } = 1 ~ \\mathrm { m m }$ and length $L = 1 0 ~ \\mathrm { c m }$ . The plasma is generated by a discharge pulse ${ \\sim } 4 5 5$ A peak current) flowing through the capillary after the introduction of hydrogen gas ${ \\sim } 1 0$ mbar) through a high-speed solenoid valve. ...
augmentation
NO
0
expert
For a given transverse beam offset, would a higher of lower plasma density be preferred to reduce the transverse dielectric wakes?
A higher plasma density screens wakes more effectively
Reasoning
Experimental_Observation_of_Space-Charge_Field_Screening.pdf
\\*Contact author: livio.verra@lnf.infn.it [1] F. F. Chen, Introduction to Plasma Physics and Controlled Fusion (Springer International Publishing, New York, 2016). [2] F. Otsuka, T. Hada, S. Shinohara, and T. Tanikawa, Penetration of a radio frequency electromagnetic field into a magnetized plasma: One-dimensional pic...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
File Name:SCATTERED_SPECTRA_FROM_INVERSE_COMPTON_SOURCES.pdf SCATTERED SPECTRA FROM INVERSE COMPTON SOURCESOPERATING AT HIGH LASER FIELDS ANDHIGH ELECTRON ENERGIES B. Terzi!‚Üí, E. Breen, P. Rogers, R. Shahan, E. Johnson, G. A. Kra"t1 Old Dominion University, Norfolk, Virginia, USA G. Wilson, Regent University, Virgini...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Table: Caption: Table 1: RMS emittances for an $1 8 \\mathrm { G e V }$ ESR lattice with fractional tunes $( \\boldsymbol { Q _ { x } } , \\boldsymbol { Q _ { y } } , \\boldsymbol { Q _ { s } } ) = ( 0 . 1 2 , 0 . 1 0 , 0 . 0 5 )$ . Body: <html><body><table><tr><td></td><td>Ea,RMs [nm]</td><td>E b,RMs [nm]</td></tr><t...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
The first of the coupled equations describes the change of energy due to a longitudinal electric field caused by a gradient of the charge distribution. The second equation can be rewritten as $d z _ { i } / d s = \\eta _ { i } / \\gamma ^ { 2 }$ meaning that relativistic particles with an energy offset change their lon...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Example of radiation spectra from CR and CB can be observed in Fig. 1. This experiment was conducted at the Mainzer Mikrotron (MAMI), where a beam of electrons of $6 0 0 \\mathrm { M e V }$ impinges on a $0 . 3 1 \\mathrm { m m }$ thick diamond crystal along the (110) plane at various angles. Directly at angle $0 \\mu ...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
As an example from [18], Fig. 3 the simulation of the radiation emission probability by a $1 0 \\mathrm { G e V }$ positron beam with $3 0 \\mu \\mathrm { r a d }$ of divergence on silicon CU with $\\lambda _ { u } = 3 3 4 \\mu \\mathrm { m }$ , amplitude $A = 1 . 2 8 \\mathrm { n m }$ and strength parameter $k = 0 . 4...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Table: Caption: Table 1: STAR Parameters Body: <html><body><table><tr><td colspan="2">Electron beam parameters</td></tr><tr><td>Energy (MeV) Bunch charge (pC)</td><td>140 500</td></tr><tr><td>Energy spread (rms, %)</td><td>0.24</td></tr><tr><td>E n,x,y (mm mrad)</td><td>1.32</td></tr><tr><td>ge,x,y(μm)</td><td>18</td...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
$$ where $\\omega _ { c }$ is the critical frequency defined at half power spectrum, $E _ { 0 }$ is the particle energy, $\\gamma$ is the relativistic factor, $\\boldsymbol { a }$ is the fine structure constant and $r _ { e }$ is the electron’s classical radius. For $\\Upsilon \\gg 1$ , the photon spectrum is given b...
augmentation
NO
0
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Turning on the effect of ideal Siberian snakes fixes the closed-orbit spin tune at $\\nu _ { 0 } ~ = ~ 1 / 2$ , which prevents the crossing of any 1st-order intrinsic resonances. Nevertheless, higher-order intrinsic resonances can be crossed by large-amplitude particles for which the spin tune deviates from _x0012__x00...
1
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
The limit in equation (4) can be further simplified by removing the shape dependence of $V$ , since the integrand is positive and is thus bounded above by the same integral for any enclosing structure. A scatterer separated from the electron by a minimum distance $d$ can be enclosed within a larger concentric hollow cy...
1
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
To overcome this deficiency, we theoretically propose a new mechanism for enhanced Smith–Purcell radiation: coupling of electrons with $\\mathrm { B I C } s ^ { 1 3 }$ . The latter have the extreme quality factors of guided modes but are, crucially, embedded in the radiation continuum, guaranteeing any resulting ...
4
NO
1
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Finally, we turn our attention to an ostensible peculiarity of the limits: equation (4) evidently diverges for lossless materials $( \\mathrm { I m } \\chi \\to 0 ) \\dot { { \\frac { . } { . } } }$ ), seemingly providing little insight. On the contrary, this divergence suggests the existence of a mechanism capable of ...
1
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
The BIC-enhancement mechanism is entirely accordant with our upper limits. Practically, silicon has non-zero loss across the visible and near-infrared wavelengths. For example, for a period of $a = 6 7 6 \\mathrm { n m }$ , the optimally enhanced radiation wavelength is $\\approx 1 { , } 0 5 0 \\mathrm { n m }$ , at wh...
4
NO
1
IPAC
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
For ELI-NP parameters (Table 1), the e#cacy of FM is evaluated as a function of $a _ { 0 }$ . The results in Fig. 6 show close to perfect recovery of the peak spectral density at $a _ { 0 } = 1$ . CONCLUSION Accurate computation of scattered spectra from ICS operating in the nonlinear Compton regime requires properly a...
1
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Author contributions Y.Y., O.D.M., I.K. and M.S. conceived the project. Y.Y. developed the analytical models and numerical calculations. A.M. prepared the sample under study. Y.Y., A.M., C.R.-C., S.E.K. and I.K. performed the experiment. Y.Y., T.C. and O.D.M. analysed the asymptotics and bulk loss of the limit. S.G.J.,...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
The Smith–Purcell effect epitomizes the potential of free-electron radiation. Consider an electron at velocity $\\beta = \\nu / c$ traversing a structure with periodicity $a$ ; it generates far-field radiation at wavelength $\\lambda$ and polar angle $\\theta$ , dictated by2 $$ \\lambda = \\frac { a } { m } \\left( \...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
Next, we specialize in the canonical Smith–Purcell set-up illustrated in Fig. 1e inset. This set-up warrants a particularly close study, given its prominent historical and practical role in free-electron radiation. Aside from the shape-independent limit (equations (5a) and (5b)), we can find a sharper limit (in per u...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
$$ written in cylindrical coordinates $( x , \\rho , \\psi )$ ; here, $K _ { n }$ is the modified Bessel function of the second kind, $k _ { \\nu } = \\omega / \\nu$ and $k _ { \\rho } = \\sqrt { k _ { \\nu } ^ { 2 } - k ^ { 2 } } =$ k/βγ $\\scriptstyle ( k = \\omega / c$ , free-space wavevector; $\\gamma = 1 / \\sqr...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
g ( \\mathbf { k } ) \\triangleq \\int f ( \\mathbf { r } ) \\mathrm { e } ^ { - i \\mathbf { k } \\cdot \\mathbf { r } } \\mathrm { d } \\mathbf { r } , g ( \\mathbf { r } ) \\triangleq \\frac { 1 } { \\left( 2 \\pi \\right) ^ { 3 } } \\int g ( \\mathbf { k } ) \\mathrm { e } ^ { i \\mathbf { k } \\cdot \\mathbf { r }...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
The grating limit (equation (6)) exhibits the same asymptotics as equations (5a) and (5b), thereby reinforcing the optimal-velocity predictions of Fig. 1c. The $( \\beta , k \\dot { d } )$ dependence of $\\mathcal { G }$ (see Fig. 2a) shows that slow (fast) electrons maximize Smith–Purcell radiation in the small (lar...
augmentation
NO
0
Expert
How do bound states in the continuum (BICs) enhance Smith-Purcell radiation?
BICs offer high-Q resonances embedded in the radiation continuum, creating large modal overlaps and enabling emission rates to diverge when phase-matched with electron trajectories.
Reasoning
Maximal_spontaneous_photon_emission_and_energy_loss_from_free_electrons.pdf
We begin our analysis by considering an electron (charge $- e$ ) of constant velocity $\\nu \\hat { \\mathbf { x } }$ traversing a generic scatterer (plasmonic or dielectric, finite or extended) of arbitrary size and material composition, as in Fig. 1a. The free current density of the electron, ${ \\bf \\dot { J } } ( ...
augmentation
NO
0
expert
How does Carilli’s interferometric method measure beam size?
By analyzing fringe visibilities from synchrotron light passing through a non-redundant aperture mask and fitting them to a Gaussian source model.
Reasoning
Carilli_2024.pdf
The derived coherences, ie. visibility fractional amplitudes (relative to the zero spacing) corrected for the voltage gains, are show in Figure 10, for both 3-hole and 5-hole data, and listed in Table II. Gain fitting is not possible with 3-hole data since the problem becomes under-constrained, so the three hole cohere...
2
Yes
0
expert
How does Carilli’s interferometric method measure beam size?
By analyzing fringe visibilities from synchrotron light passing through a non-redundant aperture mask and fitting them to a Gaussian source model.
Reasoning
Carilli_2024.pdf
dominated by a phenomenon such as CCD read noise. Figure 26 shows a plot of the mean coherences and rms of the coherences over the 30 record time series assuming no bias, and subtracting a bias of 3.7 counts per pixel. The coherences are systematically lower by about 2% with no bias subtracted, and the rms values are u...
2
Yes
0
expert
How does Carilli’s interferometric method measure beam size?
By analyzing fringe visibilities from synchrotron light passing through a non-redundant aperture mask and fitting them to a Gaussian source model.
Reasoning
Carilli_2024.pdf
Note that the target source size is $\\leq 6 0 \\mu m$ , which at a distance of $\\mathrm { 1 5 . 0 5 m }$ implies an angular size of $\\leq 0 . 8 4 \\$ . For comparison, the angular interferometric fringe spacing of our longest baseline in the mask of $2 2 . 6 \\mathrm { m m }$ at $5 4 0 ~ \\mathrm { n m }$ wavelength...
4
Yes
1
expert
How does Carilli’s interferometric method measure beam size?
By analyzing fringe visibilities from synchrotron light passing through a non-redundant aperture mask and fitting them to a Gaussian source model.
Reasoning
Carilli_2024.pdf
Notice that, for the 6-hole mask Figure 8, the u,v data points corresponding to the vertical and horizontal 16mm baseline have roughly twice the visibility amplitude as neighboring points (and relative to the 5-hole mask). This is because these are now redundantly sampled, meaning the 16mm horizontal baseline now inclu...
4
Yes
1