Source
string
Question
string
Answer
string
Question_type
string
Referenced_file(s)
string
chunk_text
string
expert_annotation
string
specific to paper
string
Label
int64
IPAC
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
File Name:SIMULATION_OF_TAPERED_CO-PROPAGATING_STRUCTURES.pdf SIMULATION OF TAPERED CO-PROPAGATING STRUCTURES FOR DIELECTRIC LASER ACCELERATOR A. Leiva Genre‚àó, G. S. Mauro, D. Mascali, G. Torrisi, G. Sorbello1, INFN-LNS, Catania, Italy 1also with Dipartimento di Ingegneria Elettrica, Elettronica e Informatica, Univer...
augmentation
NO
0
IPAC
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
Fixed Field Accelerators (FFAs) have been proposed for many applications where a large energy acceptance and rapid acceleration can be advantageous, such as muon colliders [1] and medical facilities [2–4]. A key characteristic that distinguishes FFAs from standard synchrotrons is that the accelerator parameters are a...
augmentation
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ Accordingly, in position and momentum coordinates, this reads $$ \\begin{array} { l } { \\displaystyle \\sigma _ { \\Delta P _ { z , n } } = \\sqrt [ 4 ] { \\frac { \\beta } { \\gamma } } \\sigma _ { \\Delta P _ { z } } } \\\\ { \\displaystyle \\sigma _ { \\Delta s , n } = \\sqrt [ 4 ] { \\frac { \\gamma } { \\beta ...
4
NO
1
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where $$ \\nabla _ { \\perp } \\nabla _ { \\perp } ^ { \\mathrm { T } } = \\left( { \\begin{array} { c c } { \\partial _ { x } ^ { 2 } } & { \\partial _ { x } \\partial _ { y } } \\\\ { \\partial _ { y } \\partial _ { x } } & { \\partial _ { y } ^ { 2 } } \\end{array} } \\right) $$ is the Hessian. The expansion Eq. ...
2
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
II. FIELDS AND KICKS IN PERIODIC STRUCTURES Usual particle tracking algorithms solve Maxwell’s equations with a predefined time step. Instead of that, we make use of the periodicity of the structure and apply only the kicks which are known not to average out a priori. The other field harmonics are neglected. The vali...
2
NO
0
IPAC
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
The transversal components of the accelerating mode vanish at the center of the gap. Small deviations around this stability point present transversal electric fields magnitude much lower than the longitudinal field. In the scenario where the accelerator lengths are greater, transverse focusing can be achieved using pon...
4
NO
1
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where $k _ { \\mathrm { y } }$ is given by Eq. (17). The tracking equations are where an explicit scheme is obtained by applying first the “kicks” and then the “pushes”. The adiabatic damping in the transverse planes is described by $$ A ^ { ( n ) } = \\frac { ( \\beta \\gamma ) ^ { ( n + 1 ) } } { ( \\beta ...
2
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ If the beam size is significantly smaller than the aperture $( y \\ll \\beta \\gamma c / \\omega )$ , the longitudinal equation decouples and becomes the ordinary differential equation of synchrotron motion. The transverse motion becomes linear in this case, however still dependent on the longitudinal motion via $\\...
5
NO
1
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where $\\operatorname { s i n c } ( \\cdot ) = \\sin ( \\pi \\cdot ) / ( \\pi \\cdot )$ . The electric field phasor and its spatial Fourier coefficients for the structure in Fig. 3 are plotted in Fig. 4. It has a small real part, which is coincidental, and a strong first and weak second harmonic. If the round braces...
augmentation
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
V. APPLICATIONS We apply our approach to similar experimental parameters as for the subrelativistic experiments at FAU Erlangen [3] and the relativistic experiments at SLAC [1,2]. Although the structures are idealized, the results are qualitatively recovered. As a next step, we show modifications and idealizations of t...
augmentation
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
III. TRACKING EQUATIONS In order to study the motion of particles in the fields of periodic gratings we approximate the forces by one kick per grating period and track with the symplectic Euler method. In spite of the very high gradients in DLA structures, the energy can still be seen as an adiabatic variable, as it is...
augmentation
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
allow the laser field to escape the structure, open boundaries in positive and negative y-direction are assumed. The energy gain of a particle in one cell is $$ \\underline { { E _ { z } } } ( x , y , z ) = \\sum _ { m = - \\infty } ^ { \\infty } \\underline { { e } } _ { m } ( x , y ) e ^ { - i m \\frac { 2 \\pi } { \...
augmentation
NO
0
expert
How is alternating phase focusing applied to DLAs?
drift sections between grating cells lead to jumps in the synchronous phase, which can be designed to provide net focusing.
definition
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ The derivatives in $y$ -direction can be determined by the dispersion relation for the synchronous mode. We have $$ k _ { z } = \\frac { \\omega } { \\beta c } , ~ k _ { x } = \\frac { 2 \\pi } { \\beta \\lambda _ { 0 } } \\tan { \\alpha } ~ \\mathrm { a n d } ~ k = \\frac { \\omega } { c } $$ and thus $$ k _ { y } ...
augmentation
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
For the purpose of quantifying the performance of the DRFB loop in the whole system, the amplitude ratio $\\alpha _ { \\mathrm { d r f } }$ and gain $\\gamma _ { \\mathrm { d r f } }$ are introduced as follows : $$ \\alpha _ { \\mathrm { d r f } } = \\vert \\tilde { I } _ { \\mathrm { g , d r f } } / \\tilde { I } _ { ...
augmentation
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ where $\\alpha , \\beta , \\gamma$ are the Twiss parameters of the boundary ellipse. The green curve in Fig. 7 shows the dependence of the total emittance on the cut-off threshold for the distribution in Fig.3. Indeed, the total emittance is sensitive to the distribution relative density in the range of $1 0 ^ { - 6...
augmentation
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ Z _ { _ { L } } = - 2 Z _ { _ { c c } } \\log { \\frac { S _ { 2 1 } ^ { D U T } } { S _ { 2 1 } ^ { r e f } } } . $$ $$ Z _ { T } = - \\frac { 2 c Z _ { d d } } { \\omega \\Delta ^ { 2 } } \\log \\frac { S _ { d d 2 1 } ^ { D U T } } { S _ { d d 2 1 } ^ { r e f } } . $$ Where $\\Delta = 1 0 m m$ is the interval bet...
augmentation
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
ALGORITHM IMPLEMENTATIONS Transverse emittance is an important parameter of characterizing accelerator performance. For the main Linac, dispersion is negligible and the beam size mainly determined by the betatron-oscillation and transverse emittance. The quadrupole scanning method is one of the most commonly used metho...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ where the bunch length $l$ is $$ l = \\frac { \\frac { \\pi } { 2 } + \\sqrt { \\mathcal { R } ^ { 2 } - 1 } - 1 } { k _ { n } } . $$ Evaluating the form factor at $k = k _ { n }$ produces $$ | F ( k _ { n } ) | = \\frac { 2 \\mathcal { R } } { \\mathcal { R } ^ { 2 } + \\pi - 2 } . $$ This result leads to the accel...
1
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ One can then define a normalized inductance $L _ { p u }$ with only two variables as follows: $$ { \\cal L } ( N , r _ { c o r e } , F F _ { a r } , F F _ { b r } ) = N ^ { 2 } . r _ { c o r e } . { \\cal L } _ { p u } ( F F _ { a r } , F F _ { b r } ) $$ Where $L _ { p u } ( F F _ { a r } , F F _ { b r } )$ is a pe...
1
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
Inductance value estimation The main geometric dimensions of an air-core inductor are shown in Fig.1. The design variables are the three geometric dimensions 𝑟௖௢௥௘, 𝑎௖௢௜௟, 𝑏௖௢௜௟ and the number of turns 𝑁. To calcula...
1
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ V " _ { c j } = V _ { j } \\left( 1 + \\Gamma _ { j } \\right) n _ { j } = 2 \\alpha _ { j } \\sqrt { \\alpha _ { 0 } / \\alpha _ { j } } e ^ { i \\Psi } \\cos \\Psi V _ { j } $$ Then, if such voltage is transported to the $\\mathbf { k }$ -th load via the multiplication by the turn ratio $1 / n _ { k }$ , one has e...
1
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
Table: Caption: TABLE I. Parameters and variables used throughout the paper. Body: <html><body><table><tr><td colspan="2">Parameter</td></tr><tr><td>K</td><td>Wakefield loss factor</td></tr><tr><td>βg</td><td>Normalized group velocity</td></tr><tr><td>vg</td><td>Group velocity</td></tr><tr><td>α</td><td>Attenua...
2
NO
0
IPAC
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ Where $\\alpha _ { 0 } : = { \\cal Q } _ { \\scriptscriptstyle L } / { \\cal Q } _ { 0 } , \\alpha _ { \\scriptscriptstyle k } : = \\alpha _ { 0 } \\beta _ { \\scriptscriptstyle k } , \\Psi : = \\mathrm { a t a n } ( - { \\mathrm Q } _ { \\scriptscriptstyle L } \\delta ) .$ The reflection coefficient at AA’ is...
1
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
File Name:Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf Design of a cylindrical corrugated waveguide for a collinear wakefield accelerator A. Siy ,1,2,\\* N. Behdad,1 J. Booske,1 G. Waldschmidt,2 and A. Zholents 2,† 1University of Wisconsin, Madison, Wisconsin 53715, USA 2Advanced Photon Source, Argonne Nation...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ E _ { z , n } ( s \\to \\infty ) = 2 \\kappa _ { n } q _ { 0 } \\mathrm { R e } \\{ e ^ { j k _ { n } s } F ( k _ { n } ) \\} $$ Expanding the real part $$ \\begin{array} { r } { E _ { z , n } ( s \\infty ) = 2 \\kappa _ { n } q _ { 0 } [ \\cos ( k _ { n } s ) \\mathrm { R e } \\{ F ( k _ { n } ) \\} } \\\\ { - \\s...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
IV. ELECTROMAGNETIC PARAMETERS Each synchronous eigenmode solution of the periodic structure is characterized by a wakefield loss factor $\\kappa$ , group velocity $v _ { g } ,$ and attenuation constant $\\alpha$ . These parameters determine how the electron beam interacts with the given mode as well as the propagation...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ W = \\frac { E _ { \\mathrm { a c c } } ^ { 2 } f _ { r } } { 8 \\pi a \\kappa } . $$ Referring to the plot for $\\kappa$ in Fig. 7, the power dissipation density is reduced by minimizing the corrugation period $p$ and maximizing the spacing parameter $\\xi$ . For structures with $p / a \\lesssim 0 . 5$ , the power ...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
VI. THERMAL LOADING Thermal loading of the corrugated waveguide places a limit on the maximum repetition rate $f _ { r }$ of the accelerator, where $f _ { r }$ is the number of bunches injected into the structure per second. The thermal loading depends on the electromagnetic properties of the $\\mathrm { T M } _ { 0 1 ...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ where $$ x ^ { \\prime } = \\frac { x } { \\hat { a } } , \\qquad y ^ { \\prime } = \\frac { y } { \\hat { a } } , \\qquad z ^ { \\prime } = \\frac { z } { \\hat { a } } , \\qquad \\omega ^ { \\prime } = \\frac { \\omega } { \\hat { a } } . $$ Scaling the fields by $\\hat { a } ^ { - 3 / 2 }$ keeps the stored energy...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ Q = \\frac { \\omega U } { P _ { d } } , $$ where $U$ is stored energy and $P _ { d }$ is the power dissipated in the cavity walls. The power dissipation density per unit area is $$ \\frac { d P _ { d } } { d A } = \\frac { 1 } { 2 } \\sqrt { \\frac { \\omega \\mu } { 2 \\sigma } } | { \\cal H } | ^ { 2 } . $$ In th...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ \\frac { E _ { \\mathrm { m a x } } ^ { 3 0 } t _ { p } ^ { 5 } } { \\mathrm { B D R } } = \\mathrm { c o n s t . } $$ From a design perspective, reducing the BDR is achieved by reducing the peak surface fields and the pulse length. Calculation of the absolute threshold value of the fields that induce breakdown in s...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ and the Fourier transform of the step function $$ \\mathcal { F } \\{ \\theta ( t ) \\} = \\pi \\biggl ( \\frac { 1 } { j \\pi \\omega } + \\delta ( \\omega ) \\biggr ) , $$ the wake impedance becomes $$ \\begin{array} { r } { Z _ { n | | } ( \\omega ) = \\kappa _ { n } \\Bigg [ \\pi [ \\delta ( \\omega - \\omega _ ...
augmentation
NO
0
expert
How is the transformer ratio defined?
It is the ratio of the maximum electric field behind the drive bunch to the maximum electric field within the bunch
Definition
Design_of_a_cylindrical_corrugated_waveguide.pdf.pdf
$$ \\begin{array} { l } { \\displaystyle P ^ { 1 / 2 } ( z , t ) = \\sqrt { \\frac { 2 \\kappa q _ { 0 } ^ { 2 } | F | ^ { 2 } v _ { g } } { 1 - \\beta _ { g } } } e ^ { \\frac { - \\alpha ( v _ { g } t - \\beta _ { g } z ) } { 1 - \\beta _ { g } } } \\cos { \\left[ \\omega \\left( t - \\frac { z } { c } \\right) \\rig...
augmentation
NO
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ V = q e _ { 1 } \\left[ \\frac { \\lambda _ { g z } } { 2 \\pi } \\cosh \\left( \\frac { \\omega y } { \\beta \\gamma c } \\right) \\sin \\left( \\frac { 2 \\pi s } { \\lambda _ { g z } } \\right) - s \\cos \\varphi _ { s } \\right] . $$ This potential and its adiabatic change with $\\beta$ is illustrated in Fig. 8....
4
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ V = q e _ { 1 } \\frac { \\lambda _ { 0 } } { 2 \\pi } \\mathrm { c o s h } \\left( \\frac { \\omega \\tan \\alpha } { c } y \\right) \\cos { \\left[ \\frac { \\omega } { c } ( \\Delta s + x \\tan \\alpha ) \\right] } . $$ The equations of motion become $$ { \\ddot { x } } = { \\frac { q e _ { 1 } } { m _ { e } \\ga...
4
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
V. APPLICATIONS We apply our approach to similar experimental parameters as for the subrelativistic experiments at FAU Erlangen [3] and the relativistic experiments at SLAC [1,2]. Although the structures are idealized, the results are qualitatively recovered. As a next step, we show modifications and idealizations of t...
4
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ describes the acceleration ramp, where the synchronous phase $\\varphi _ { \\mathrm { s } }$ can be chosen arbitrarily \in each grating cell. The variables $e _ { 1 } , \\lambda _ { g z } , W _ { 0 } , \\beta , \\gamma , \\varphi _ { \\mathrm { s } }$ and all variables \in Eq. (24) are stored as arrays indexed by th...
5
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ \\underline { { e } } _ { m } ( x , y ) = \\underline { { e } } _ { m } ( 0 , 0 ) \\cosh ( i k _ { y } y ) e ^ { i k _ { x } x } , $$ where $\\lambda _ { g x } = \\lambda _ { g z } /$ tan $\\alpha$ . A map of the energy gain and transverse kicks for the grating in Fig. 6 can be seen in Fig. 7 for a grating tilt angl...
4
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where $W _ { 0 } = \\gamma m _ { e } c ^ { 2 }$ and $p _ { z 0 } = \\beta \\gamma m _ { e } c$ . The particle at the synchronous phase $\\varphi _ { \\mathrm { s } }$ has $\\Delta \\delta = 0$ , i.e., its energy gain is entirely described by the acceleration ramp. The energy gain $\\Delta W$ is given by Eq. (7) and ...
5
Yes
1
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ and are depicted as arrows in Fig. 7. For the numerical results, the gradient is determined by finite differences in MATLAB [8]. Note that $- i k _ { y } \\in \\mathbb { R } ^ { + }$ , i.e., the kick in $x$ -direction is in phase with the acceleration while the kick in $y$ -direction is 90 degrees shifted. For a par...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ \\sigma _ { \\Delta W } = \\frac { c _ { 0 } } { \\lambda _ { 0 } } \\sqrt { - 2 \\pi \\lambda _ { g z } m _ { e } \\gamma ^ { 3 } q e _ { 1 } \\sin \\varphi _ { s } } \\sigma _ { \\Delta s } . $$ For a slow change of the potential and filling the bucket only up to a small fraction, the phase space area given by $\\...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
Although the experimentally demonstrated gradients in DLA structures are very promising, there are still crucial challenges to create a miniaturized DLA-based particle accelerator. So far the experimentally achieved gradients could only be used to increase the beam’s energy spread and not for coherent acceleration. M...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
We plan to achieve such phase jumps by inserting drift sections as already outlined in Fig. 1. Other options are to modify the accelerating Fourier coefficient in each cell, e.g., by phase masking within the structure or by active phase control of individual parts of the laser pulse. In general, we believe that this pa...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ \\mathbf { M } = \\langle \\vec { r } \\vec { r } ^ { T } \\rangle , $$ where the average is taken component-wise. In the absence of nonlinearities, particular emittances are conserved. That is in the case of coupling only the 6D emittance given by $$ \\varepsilon _ { 6 D } = \\sqrt { \\operatorname* { d e t } { \\b...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where $$ \\nabla _ { \\perp } \\nabla _ { \\perp } ^ { \\mathrm { T } } = \\left( { \\begin{array} { c c } { \\partial _ { x } ^ { 2 } } & { \\partial _ { x } \\partial _ { y } } \\\\ { \\partial _ { y } \\partial _ { x } } & { \\partial _ { y } ^ { 2 } } \\end{array} } \\right) $$ is the Hessian. The expansion Eq. ...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ If the beam size is significantly smaller than the aperture $( y \\ll \\beta \\gamma c / \\omega )$ , the longitudinal equation decouples and becomes the ordinary differential equation of synchrotron motion. The transverse motion becomes linear in this case, however still dependent on the longitudinal motion via $\\...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
With no loss of generality, we restrict ourselves to symmetric grating structures driven from both lateral sides. This makes sure that the axis of symmetry is in the center and the fields have a cosh profile. In the case of nonsymmetric structures or nonsymmetric driving, the fields will have an exponential or an off-a...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
C. Dynamics in tilted gratings Finally, we address the tilted grating with the same laser parameters and a bunched electron beam with parameters $\\varepsilon _ { x } = \\varepsilon _ { y } = 1 \\ \\mathrm { n m } , \\sigma _ { x } = 1 \\ \\mu \\mathrm { m } , \\sigma _ { y } = 0 . 4 \\mu \\mathrm { m } .$ $\\sigma _ {...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ where the energy momentum differential $\\Delta p _ { \\| } = \\Delta W / ( \\beta c )$ was applied. Moreover, if the phase-synchronicity condition [Eq. (6)] is fulfilled, the kick becomes $$ \\begin{array} { l } { { \\displaystyle \\Delta \\vec { p } _ { \\perp } ( x , y ; s ) = - \\frac { \\lambda _ { g z } ^ { 2 ...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
Both the numerical and the analytical approach can be generalized from ordinary DLA gratings to tilted DLA gratings, which have been proposed as deflectors or laser driven undulators [12–14]. Such a grating is depicted in Fig. 2. However, since our code does not include the radiation fields, a dedicated code as, e.g....
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
$$ in the usual units of $\\textrm { m }$ rad and eVs, respectively. The analysis of emittance coupling by means of the eigen-emittances $$ \\varepsilon _ { \\mathrm { e i g } , i } = \\mathrm { e i g s } ( \\mathbf { J } \\mathbf { M } ) , $$ where $\\mathbf { J }$ is the symplectic matrix, is also possible with our c...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
For an adiabatic Hamiltonian and if stable orbits exist, a matched locally Gaussian distribution is given by $$ f = C e ^ { - H / \\langle H \\rangle } $$ and a locally elliptic (Hofmann-Pedersen [23]) matched distribution is given by $$ f = C { \\sqrt { H _ { \\operatorname* { m a x } } - H } } . $$ The normalization ...
augmentation
Yes
0
expert
Is it accurate to only consider the first harmonic?
the higher nonsynchronous harmonics average out. It can be shown, that their second order (ponderomotive) contribution is also small.
reasoning
Beam_dynamics_analysis_of_dielectric_laser_acceleration.pdf
For subrelativistic accelerators, the grating needs to be chirped in period length in order to always fulfill Eq. (6) on the energy ramp. The change of period length is given by the energy velocity differential $$ \\frac { \\Delta z } { \\lambda _ { g z } } = \\frac { 1 } { \\beta ^ { 2 } \\gamma ^ { 2 } } \\frac { \\D...
augmentation
Yes
0
IPAC
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
C-BAND INJECTOR DESIGN We have designed two injectors. One design is plug-free and is shown in Fig. 2. This design focuses on the tuning and high gradient testing of the RF cavity without a high QE photocathode or plug [2]. The design is very similar to the plug-insert design, as shown by the RF parameters in Table 2 ....
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ If the phase of the radiation wave advances by $\\pi$ between $A$ and $B$ , the electromagnetic field of the radiation adds coherently3. The light moves on a straight line $\\overline { { A B } }$ that is slightly shorter than the sinusoidal electron trajectory $\\widetilde { A B }$ $$ { \\frac { \\lambda } { 2 c } ...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ j _ { x } + j _ { y } + j _ { z } = 4 . $$ This means that the damping is not uniformly distributed along the three sub-spaces of the phase space (horizontal, vertical and longitudinal), but it is split according to specific partition numbers. These partition numbers are determined by the accelerator lattice, which ...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
– Auger electrons: similarly to fluorescence, this effect starts with the ionization or excitation of an inner-shell electron due to the interaction with the X-ray photon. This leaves a vacancy in the inner shell, which is then filled with an outer-shell electron. However, instead of releasing the excess energy as a ...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
d) . . . requires the rotation of the sample around three orthogonal axes I.10.7.52 Undulator radiation Derive the formula for the fundamental wavelength of undulator radiation emitted at a small angle $\\theta$ : $$ \\lambda = \\frac { \\lambda _ { u } } { 2 \\gamma ^ { 2 } } \\left( 1 + \\frac { K ^ { 2 } } { 2 } + \...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
How would you measure this radiation? I.10.7.27 Superconducting undulators What is the advantage of using undulators made with superconducting coils, in comparison to permanentmagnet arrays? What are drawbacks? I.10.7.28 In-vacuum undulators What are the advantages of using in-vacuum undulators? What are possible diffi...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ Equation (I.10.16) becomes $$ \\begin{array} { r c l } { { \\displaystyle \\frac { \\lambda } { 2 c } } } & { { = } } & { { \\displaystyle \\frac { \\lambda _ { u } } { 2 \\beta c } \\left( 1 + \\frac { K ^ { 2 } } { 4 \\gamma ^ { 2 } } \\right) - \\frac { \\lambda _ { u } } { 2 c } } } \\\\ { { \\Longrightarrow } }...
1
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
– The Lorentz factor $\\gamma$ , – The magnetic field to bend the beam (assume for simplicity that the ring consists of a uniform dipole field), – The critical energy of the synchrotron radiation, – The energy emitted by each electron through synchrotron radiation in one turn. I.10.7.7 Future Circular Collider:...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
I.10.7.45 Crystals Which of the following are crystalline (more than one answer is may be correct)? $a$ ) The glass on the screen of my mobile phone $b$ ) The sapphire glass on an expensive watch c) Asbestos d) Icing sugar e) Sapphire $f$ ) Fused silica g) Snowflakes $h$ ) Paracetamol (Acetaminophen) powder in capsules...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
File Name:Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation.pdf Chapter I.10 Synchrotron radiation Rasmus Ischebeck Paul Scherrer Institut, Villigen, Switzerland Electrons circulating in a storage ring emit synchrotron radiation. The spectrum of this powerful radiation spans from the far infrared to the $\\boldsymbol {...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ which is Bragg’s law. Note that contrary to the diffraction on a two-dimensional surface, which is often considered fir visible light, $\\mathrm { \\Delta } \\mathrm { X }$ -rays diffract on a three-dimensional crystal lattice. In this case, not only the exit angle matters, but also the incoming angle must fulfill...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ respectively. The solution to Maxwell’s equations for this time-varying charge and current density can be found by using the wave equation for the electromagnetic potentials. In the Lorentz gauge, this wave equation reads $$ \\vec { \\nabla } ^ { 2 } \\Phi - \\frac { 1 } { c ^ { 2 } } \\frac { \\partial ^ { 2 } \\...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
– Vacuum system: as a result of the smaller inner bore of the magnets, the vacuum chamber diameter needs to be reduced to a point where a conventional pumping system becomes difficult to implement. A key enabling technology is the use of a distributed getter pump system, where the entire vacuum chamber is coated with...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ After the emission of a photon, the action of our single electron is $$ \\begin{array} { r c l } { { J _ { y } ^ { \\prime } } } & { { = } } & { { \\displaystyle \\frac { 1 } { 2 } \\gamma _ { y } y ^ { 2 } + \\alpha _ { y } y p _ { y } \\left( 1 - \\frac { d p } { P _ { 0 } } \\right) + \\frac { 1 } { 2 } \\beta _ ...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ Computing the photon flux $\\dot { N } _ { \\gamma }$ for an undulator is even more elaborate than the calculation for a single dipole, and we just cite the result [2] $$ { \\dot { N } } _ { \\gamma } = 1 . 4 3 \\cdot 1 0 ^ { 1 4 } N I _ { b } Q _ { n } ( K ) , $$ where $$ Q _ { n } ( K ) = \\frac { 1 + K ^ { 2 } / ...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ with a horizontal damping time $$ \\tau _ { x } = \\frac { 2 } { j _ { x } } \\frac { E _ { 0 } } { U _ { 0 } } T _ { 0 } . $$ All effects related to the dispersion are summarized in the horizontal partition number $j _ { x }$ $$ j _ { x } = 1 - { \\frac { I _ { 4 } } { I _ { 2 } } } . $$ The second synchrotron radi...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
I.10.7.35 Instrumentation How would you measure the bunch length in a synchrotron? I.10.7.36 Instrumentation How would you measure the stability of the orbit in a storage ring? I.10.7.37 Detection What possibilities exist to detect X-Rays? How has the development of X-ray detectors influenced experiments at synchrotron...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
applications in Section I.10.6. The total radiated power per particle, obtained by integrating over the spectrum, is $$ P _ { \\gamma } = \\frac { e ^ { 2 } c } { 6 \\pi \\varepsilon _ { 0 } } \\frac { \\beta ^ { 4 } \\gamma ^ { 4 } } { \\rho ^ { 2 } } . $$ The energy lost by a particle on a circular orbit, i.e. in an ...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ where $\\vartheta$ is the angle at which the photon is scattered. I.10.5.2 Scattering of $\\mathbf { X }$ -rays on atoms In the case of photon energies less than a few keV, the wavelength is longer than the size of the atom. The scattering is then coherent, i.e., the phases of the scattered waves from different part...
augmentation
NO
0
expert
What are insertion devices?
They are periodic magnetic structures, such as undulators and wigglers, placed in straight sections to generate radiation.
Definition
Ischebeck_-_2024_-_I.10_—_Synchrotron_radiation
$$ where $J$ is the Bessel function of the first kind. As $K$ increases, the higher harmonics play a more signicificant role, but the fundamental harmonic always has the highest flux. I.10.3 Effects of the emission of radiation on beam dynamics In this section, we will delve deeper into the interplay between the radiat...
augmentation
NO
0
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
The evaluation of the beam size resolution of the screen profile monitors is usually first performed in a laboratory, using calibrated optical targets, and then sometimes checked in the beam itself. However, the in-beam checks can be difficult to execute properly without damaging the scintillators. The simplest way to ...
4
Yes
1
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
However, the first experimental use of these devices after installation to evaluate the emittance of the electron beam at SwissFEL showed that the resolution was significantly worse and was found to be between 20 and $4 0 \\ \\mu \\mathrm { m }$ when using the filters.15–17 An investigation of the filters showed that...
4
Yes
1
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
$$ \\sigma _ { t o t } ^ { 2 } = \\sigma _ { s c r } ^ { 2 } + \\frac { \\beta \\varepsilon } { \\gamma } . $$ It is clear from the above equation that by measuring the electron beam sizes $\\sigma _ { \\mathrm { t o t } }$ for different electron beam energies $\\gamma _ { : }$ , one can reconstruct the screen resoluti...
4
Yes
1
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
File Name:[ScreenUpgrade]RevSciInst_94_073301(2023).pdf Testing high-resolution transverse profile monitors by measuring the dependence of the electron beam size on the beam energy at SwissFEL Pavle Juranić  ; Eduard Prat  $\\textcircled{1}$ DCheck for updates Articles You May Be Interested In Perspective: Oppo...
2
Yes
0
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
V. CONCLUSION The method presented in this article shows the ability to improve the screen resolution by using high-quality filters and dynamic focusing. The profile monitor resolution is reconstructed in a gentle way by measuring the electron beam sizes for different beam energies. Our results show a significant impro...
4
Yes
1
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
$^ { 8 } { \\mathrm { C } } .$ Wiebers, M. Hoz, G. Kube, D. Noelle, G. Priebe, and H.-C. Schroeder, in Proceedings of the 2nd International Beam Instrumentation Conference (IBIC 2013) (JACOW, Oxford, UK, 16-19 September 2013), p. 807. ${ ^ \\circ _ { \\mathrm { H } } } .$ D. T. ChoiKim, M. Chae, J. Hong, S.-J. Park, an...
augmentation
Yes
0
Expert
What are the filter settings for the DSCR screens?
The screens use two filters with 10% and 1% attenuation, that give attenuations of 10%, 1%, and 0.1%.
Fact
[ScreenUpgrade]RevSciInst_94_073301(2023).pdf
$^ { 1 4 } \\mathrm { M }$ . Castellano and V. A. Verzilov, Phys. Rev. Spec. Top.–Accel. Beams 1, 062801 (1998). $^ { 1 5 } \\mathrm { E }$ . Prat, P. Craievich, P. Dijkstal, S. Di Mitri, E. Ferrari, T. G. Lucas, A. Malyzhenkov, G. Perosa, S. Reiche, and T. Schietinger, Phys. Rev. Accel. Beams 25, 104401 (2022). $^ {...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
$$ The design obtained from the gradient-based technique of adaptive moment estimation $( \\mathrm { A d a m } ) ^ { 2 . 5 }$ is depicted in Figure 1b. The structure features two rows of pillars, shifted by half a period with respect to each other. The rows of pillars are followed by three slabs on each side, which can...
1
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
$$ \\lambda = \\frac { a } { m } \\Biggl ( \\frac { 1 } { \\beta } - \\cos { \\theta } \\Biggr ) $$ where $\\beta$ is the normalized velocity of the electrons, a is the periodicity of the structure, and $m$ is the mode order. Smith‚àí Purcell emission from regular metallic grating surfaces has been observed in nume...
1
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
The geometric acceptance angle of the Michelson interferometer $\\Delta \\theta$ in the plane of the electron beam and the THz radiation defines the accepted bandwidth of the setup. According to the Smith‚àíPurcell relation (eq 1), it is given by $$ \\Delta \\lambda = a \\sin \\theta \\Delta \\theta $$ Around the o...
1
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
An in-vacuum PMMA lens with a diameter of $2 5 \\mathrm { ~ m m }$ collimated parts of the emitted radiation. A Michelson interferometer was used to measure the first-order autocorrelation of the electromagnetic pulse and to obtain its power spectrum via Fourier transform (Figure 2b and Methods). The measured spectrum ...
1
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
File Name:hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf Inverse-Designed Narrowband THz Radiator for Ultrarelativistic Electrons Benedikt Hermann,# Urs Haeusler,# Gyanendra Yadav, Adrian Kirchner, Thomas Feurer, Carsten Welsch, Peter Hommelhoff, and Rasmus Ischebeck\\* ...
1
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
RESULTS The goal of our inverse design optimization was a narrowband dielectric Smith‚àíPurcell radiator for ultrarelativistic electrons $\\mathit { \\check { E } } = 3 . 2 \\ \\mathrm { G e V }$ , $\\gamma \\approx 6 0 0 0 ,$ ). To simplify the collection of the THz radiation, a periodicity of $a = \\lambda$ was chose...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
$$ { \\bf J } ( x , y , \\omega ) = \\frac { q } { 2 \\pi } { \\cdot } ( 2 \\pi \\sigma _ { x } ^ { 2 } ) ^ { - 1 / 2 } { \\cdot } e ^ { - x ^ { 2 } / 2 \\sigma _ { x } ^ { 2 } } { \\cdot } e ^ { - i k _ { \\mathrm { y } } y } \\hat { \\bf y } $$ with the electron wavevector $k _ { y } = 2 \\pi / \\beta \\lambda$ and t...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
The objective function $G$ , quantifying the performance of a design $\\phi ,$ is given by the line integral of the Poynting vector $\\begin{array} { r } { { \\bf S } ( x , y ) = \\mathrm { R e } \\left\\{ \\frac { 1 } { 2 } { \\bf E } \\times { \\bf H } ^ { * } \\right\\} } \\end{array}$ in the $x$ -direction along th...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
We drove the structure with electron bunches with a duration of approximately 30 fs (RMS), which is much shorter than the resonant wavelength corresponding to a period of 3 ps. Hence, we expect to see the coherent addition of radiated fields. To experimentally verify this, we varied the bunch charge. Figure 4 shows the...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
During and after our experiments, the structure did not show any signs of performance degradation or visible damage. It was used continuously for eight hours with a bunch charge of approximately $1 0 ~ \\mathrm { p C }$ at a pulse repetition rate of $1 \\ \\mathrm { H z }$ . CONCLUSION The here-presented beam-synchrono...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
Our work naturally extends to the field of subrelativistic electrons. Here, simultaneous arrival of THz radiation and electron bunches is readily achieved by compensating for the higher velocity of the radiation with a longer path length (Figure 5b). Besides its application for pump‚àíprobe experiments, our structure c...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
$$ \\epsilon _ { r } ( x , y ) = \\epsilon _ { \\mathrm { m i n } } + ( \\epsilon _ { \\mathrm { m a x } } - \\epsilon _ { \\mathrm { m i n } } ) { \\cdot } \\frac { 1 } { 2 } ( 1 + \\operatorname { t a n h } \\alpha \\phi ( x , y ) ) $$ where large values of $\\alpha$ yield a close-to-binary design with few values bet...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
Ultrarelativistic Optimization. The simulation of ultrarelativistic electrons poses challenges that have so far prevented inverse design in this regime.33 Here, we report on two main challenges. First, the electron velocity is close to the speed of light $( \\beta = 0 . 9 9 9 9 9 9 9 8 5$ for $E = 3 . 2 \\mathrm { G e ...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
The second difficulty arises from the long-range evanescent waves of ultrarelativistic electrons. The spectral density of the electric field of a line charge decays with $\\bar { \\exp ( - \\kappa | x | ) }$ , where $\\kappa =$ $2 \\pi / \\beta \\gamma \\lambda$ , with $\\beta \\approx 1$ and $\\gamma \\approx 6 0 0 0$...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
Simulations. The 3D frequency-domain simulation was performed in COMSOL, based on the finite element method. The simulation cell, as shown in the lower right inset of Figure 1c, consists of a single unit cell of the grating, with a height of 4 mm and periodic boundaries along the electron propagation direction. An opti...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
Accelerator Setup. The experiments used $1 0 ~ \\mathrm { p C }$ electron bunches from the $3 . 2 \\mathrm { G e V }$ Athos beamline of SwissFEL27 operated at a pulse repetition rate of $1 \\ \\mathrm { H z }$ to keep particle losses during alignment at a tolerable level. The standard bunch charge at SwissFEL is $2 0 0...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
A bunch length of 30 fs (RMS) was measured for similar machine settings in a separate shift with a transverse deflecting cavity (TDC) in the Aramis beamline of the accelerator. Therefore, we expect the longitudinal dimension of the electron beam at the ACHIP chamber to be on the order of $1 0 \\ \\mu \\mathrm m ,$ , al...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
Michelson Interferometer and THz Detector. For the spectrum measurements, we installed a Michelson interferometer outside the vacuum chamber. The THz pulse was first sent through an in-vacuum lens made of PMMA with a diameter of $2 5 \\ \\mathrm { m m }$ and a focal length of $1 0 0 ~ \\mathrm { { m m } }$ . The lens c...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
A typical autocorrelation measurement for a charge of 9.4 pC is depicted in Figure 2b. The shape of the autocorrelation is not perfectly symmetric in amplitude and stage position. The amplitude asymmetry could be a result of a nonlinear detector response (onset of saturation). This is in agreement with the slight devia...
augmentation
Yes
0
Expert
What central wavelength of THz radiation was measured experimentally?
Approximately 881 ?m
Fact
hermann-et-al-2022-inverse-designed-narrowband-thz-radiator-for-ultrarelativistic-electrons.pdf
ACS PHOTONICS READ Quasi-BIC Modes in All-Dielectric Slotted Nanoantennas for Enhanced $\\mathbf { E r ^ { 3 + } }$ Emission Boris Kalinic, Giovanni Mattei, et al.JANUARY 18, 2023 ACS PHOTONICS READ Get More Suggestions >
augmentation
Yes
0