luigifaillacehbeb13

Recent Advancements of RF Guns

Luigi Faillace RadiaBeam Technologies, Santa Monica CA

Physics and Applications of High Brightness Beams – Towards a Fifth Generation light source San Juan, Puerto Rico March 25-28, 2013

Outline

v  RF photoinjectors for brighter beams v  Trieste gun

•  RF design •  Machining/Cold-Test/Brazing/Tuning •  Installation •  High-power Conditioning

v  Super gun •  GALAXIE project •  High charge operation

v  Status of other RF guns

v  Conclusions

Physics and Applications of High Brightness Beams – Towards a Fifth Generation light source

v  Crucial advancements of FEL-based light sources (SASE XFELs and ERLs), able to achieve high brightness levels, have been achieved by ever brighter electron sources, where the beam brightness is defined as

v  Strong requirement for low-emittance in order to allow an FEL to

operate at a certain wavelength

v  Current 4th generation, as well as the future 5th generation, light sources greatly rely on beam quality, unlike previous generations, since they are high-gain and single-pass free electron lasers.

v  Although it is possible to operate in principle at any given emittance,

high-brightness beams will reduce the cost of the undulator (gain length ) and the number Linac sections used for energy gain.

Note: undulator cost in 2005 dollars $0.35M/m, Linac cost $20M/GeV.

!N"!#4$

Lg !Bn"1/3

BN !2I

!N ,x!N ,y

Frank Stephan, NC RF photo injectors for FELs, LA3NET Workshop, CERN, 20.-‐22.2.2013

Why brighter electron beams?


John Power, AAC 2010

!photo =" x

!# !$eff3mc2

!eff = !work !!Schottky ! x =r2=

Qb

4"#0Ea

Qb = bunch chargeEa =Applied Electric Field

Higher applied fields at the cathode à lower thermal emiHance!

Why Radio-‐Frequency (RF) Photoinjectors?

* Zhi Liu, SLAC-‐PUB12108, Sept 2006 ** D.H. Dowell, et al., Nucl. Instr. and Meth. A (2010) doi:10.1016/j.nima.2010.03.104

v RF guns are able to provide very high currents and low emittances à high brightness! v The phenomenon by which the electron beam is created inside an RF photoinjector is known as

photoemission v The electrons are extracted out of the material upon absorption photons with energy greater than

the work function Φwork

v Very high electron density beam can be achieved by photoemission (beyond 100 kA/cm2 for metals, 108 A/cm2 for CsBr*)

v  Beam transverse and longitudinal characteristics can be manipulated by properly shaping the laser pulse

v High fields are necessary to preserve initial beam high brightness (possible inside RF structure because able to withstand breadowns better than DC ones)

!photo =Qb(!! !"eff )12#$0mc

2Ea


Main elements of an Electron Injector using an RF Gun

RF GUN

Solenoid/emittance compensation

Accelerating Section

Linearizer

Bunch compressor chicane

v  Emission and Initial Acceleration (Radio-Frequency Gun) v  Beam Conditioning (Solenoid for emittance compenstion) v Acceleration (Linacs for emittance preservation and chirping for bunch compressor, e.g. chicanes)


RF Gun for the Fermi FEL at Sincrotrone Trieste

The Radio-Frequency (RF) of design a NCRF Gun for the Sincrotrone Trieste facility, which is termed “FERMI RF Gun 2” is based on the UCLA-University of Rome-INFN-LNF high repetition rate photoinjector*, which was improved upon the LCLS# version by use of larger radius of curvature of the input coupler irises, by the inclusion of an enhanced cooling channels system that allows for cathode exchangeable cathode plate and by using a single-feed scheme for more compactness.

*L. Faillace et al., “ An Ultra-high repetition rate S- band RF Gun”, FEL Conference 2008 #C.Limborg et al., “RF Design of the LCLS Gun”, LCLS Technical Note LCLS-TN-05-3 (Stanford,2005). #D.H. Dowell et al., “The development of the Linac Coherent Light Source RF Gun”, SLAC Menlo Park CA, published in the ICFA Beam Dynamics Newsletter


Fermi II Gun

Ø  Operation frequency 2.998 GHz, π-mode Ø  1.6 cell gun Ø  Single feed

Ø  Race track geometry Ø  “z-coupling”

Ø  Elliptical coupling irises Ø  50 Hz repetition rate Ø  Removable Cathode Ø  Numeric codes for simulations: HFSS/Ansys,

Superfish.

ü simpler RF power system than the case of dual feed ü Avoid phase shift between the two input waves in the case of dual feed ü dummy waveguide to diminish dipole field

ü To minimize quadrupole field

ü To reduce H field, i.e. temperature rise (RF pulsed heating), at the coupling slots

ü To decrease surface electric field (cause of RF breakdowns)

RadiaBeam/UCLA RF Gun for the Fermi FEL at Sincrotrone Trieste (FERMI II Gun)


RF probe

grid

Laser port

3 step taper

Main Rf Parameters


Input RF waveguide

Vacuum port

ktHTcRF

επρσδ '|| 2||

=Δ

RF pulsed heating, due to surface magnetic field, causes a temperature gradient ΔT on the metal at each RF pulse, followed by cooling between pulses causing surface fatigue (cyclic stress)àmicrocracks that may decrease the heat conductivity and in some conditions cause RF breakdown*.

ΔT = 45°C

below the safe limit!

•  ΔT is independent of the surface thickness and the cooling system. Practical “safe limit” in case of copper and in S-Band is about 50°C.

•  Crucial areas are the waveguide-to-coupling-cell and laser port irises

•  “rounded irises” are used (8mm diameter).

•  The peak surface magnetic field is nearly H||= 3.9*105 A/m @ input RF power = 9.8 MW

tRF : pulse length σ : electrical conductivity δ : skin depth ρ’ : density cε :specific heat k : thermal conductivity

Rf Pulsed Heating

*V. Dolgashev, “High Fields in Couplers of X-band Accelerating Structures”, Proceed. Pac 2003, Portland, Oregon, (2003). **D.P. Pritzkau, “RF Pulsed Heating”, SLAC-Report-577, Ph.D. Dissertation, Stanford University, 2001


**

ΔT=39.6 °C

ΔT=34.6 °C

f = 2.998GHz Pulse length = 3μs


Rf Pulsed Heating

Dipole and Quadrupole Components

Cross section of the full cell. The field is calculated along circumferences with different radii R and for different values of the offset D, by which the two cell arcs are drifted apart.

Ø  A dummy waveguide (higher cut-off frequency), symmetric to the RF input waveguide, allows to erase the field dipole component.

Ø  The quadrupole component is eliminated by using a “race track” geometry. Ø  Higher order modes are considered negligible. RF input power

Dummy waveguide Below cut-‐off @2.856GHz


H! (r,! ) = H!n (r)n=0

!

" cos(n! )

H!n (r) =2"

H! (r,! )0

"

! cos(n! )d!

n=0 Hϕ0 (r) H0 (r)=Monopole

n=1 Hϕ1 (r) H1(r)=Dipole

n=2 Hϕ2 (r) H2(r)=Quadrupole

Values of the Off-‐set D for which field components where calculated using HFSS D=2mm, 3mm 4mm

Data overlap for all D values. The monopole component is unaltered.

There is a D value for which the dipole and quadrupole components are eliminated!

D=2mm, 3mm, 4mm

D=2mm, 3mm, 4mm

D=2mm, 3mm, 4mm

D=3.45mm


Dipole and Quadrupole Components

Fourier series

nth component

Only 12 bolts No contact at core

Thermal Analysis Results

Worst case scenario: NO contact between copper layers (radiation only) Intermediate case: contact only happens at the 12 bolts location Best case: full contact between the two layers

Worst

Intermediate

Best


Stress Analysis Results

In all the simulated cases (that is changing the pushing force, surfaces heat transfer…), the stress on copper parts is always below the yield strength of 70MPa (for soft copper).

Stress

Deformation


The deformation is below 25 microns for the cell surfaces.

ST gun a(er final tuning (SLAC Dec13, 2012)

v All the gun parts were machined in-house.

v Cold test measurements (scattering parameters, resonant frequency, other main RF parameters) carried out at SLAC by using a clamping setup (Sept 2012)

v  Impeccable brazing (no leaks after any brazing cycle step) performed by the brazing team at the SLAC klystron dept. under supervision of John van Pelt.

RF gun Machining, Cold test and Brazing


19 °C, 40% humidity

Measurement HFSS

Frequency 2.99801 GHz (19 C, 40% humidity)

2.998GHz

Mode separaAon 14.5 MHz 14.2 MHz

Q0 13,350 13,750

Coupling beta 1.85 1.8

RF Gun tuning and Field measurements

v  The tuning of the gun resonant frequency (≈1MHz) was carried out by using bi-directional deformation tuners

v  On-axis electric field measured in a

bead-drop setup by using a 2mm diameter dielectric bead


Air Vacuum

Frequency Shift

2.99801 GHz (19 C, 40% humidity)

2.998808GHz

Water temperature

Around 39°C

Installation January 2013 initial tests

v  Installation of the gun started on Jan 4th 2013 at Sincrotrone Trieste

v  The gun was brought under vacuum in a test area to check if any leaks were present as well as the frequency shift that resulted to be about 800 kHz, as expected

v  The operating temperature of 39°C allowed for operation at exactly 2.99801 GHz, as it was verified. (good agreement with theory prediction of df/dT≈-50kHz/°C)


Acknowledgements to the team Luigi Faillace, RF design Pedro Frigola, project manager Ron Agustsson, VP of Engineering Hristo Badakov, Mechanical Engineer UCLA collaboration

Installation January 2013 tunnel

v  A dedicated area for high-power gun testing is located behind the current RF gun station

v  The ST gun was installed in this area to start high-power conditioning


Power and vacuum monitoring


Temperature Tuning at 10 Hz and 50Hz


Frequency monitoring

from Reflected power

from RF probe

-0.3°C at 10Hz

Power Waveforms (11 MW and 1.5 µs)

v  Operation at 10Hz à ΔT = -0.3 °C

v  Operation at 50Hz à ΔT = -2 °C

Breakdown monitoring during high-power conditioning


Input RF power = 11MW RF pulse = 1.5 µs Monitoring time = 18 hours

2.4*10-9 mbar

Excellent vacuum level

The GALAXIE Project

GALAXIE (GV-per-meter AcceLerator And X-ray-source Integrated Experiment) is a program to develop an all-optical, very high field accelerator and undulator integrated SASE FEL system based on dielectric laser-excited structures that support >GV/m fields.

v  Injector: high field gun with a magnetized cathode (1pC,1ps beam with angular momentum content) à  the Super Gun v  Transformer: beam passing through a skew-quad triplet that splits the emittances ( = 2*10-9 mrad ) v  Dielectric photonic structure: acceleration v  Inverse Transfomer: the emittance splitting process is reversed after acceleration and before the undulator

to avoid gain-degrading multiple-transverse-mode operation of the FEL

e- RF gun

Accelerator structure

A. Valloni et al., An Asymmetric Emittance Electron Source for the GALAXIE Dielectric-Laser Accelerator Injector.


!! "!02

L!+ ! 2L! = !0

2 + L2R. Brinkmann et al., Phys. Rev. ST-AB 4, 053501 (2001)5 P. Piot et al., Phys. Rev. ST-AB 9, 031001 (2006)

L >> !0

!!

The “SUPER GUN” Considerations

v  Flexibility to run beams with very low transverse size and high charge: E0sin(Φ0) >Edec, Ez,SC=

v  Why not X-Band gun where E0 can go up to 200MV/m??? E0=200MV/m (best case scenario), 11.424GHz, α=0.9 à Φ0=40° à Ea=120MV/m à lower than the Super Gun case!

0 10 20 30 40 50 60 70 80 900

1

2

3

4

5

6

7

0

To satisfy Kim’s model α>0.9 Φ0>45°C

v  Electric field E0 at the cathode (emission area) = 160MV/m, 30% higher than the state-of-the art for S-band guns.

v  Lower thermal emittance where Ea is the applied field Ea=E0sin(Φ0) where Φ0 is the beam injection phase

v  Φ0à Ea ???

! =eE02mc2k

k =! c

E0=160MV/m, 2.856GHz and 1pC (Galaxie case) α=2.6 à Φ0=75° à Ea=150MV/m à in theory possible to have = 3.5*10-9 mrad, relaxing the spec on the B field required for the emittance splitting process!

Reduced vector potential

C o n d i t i o n f o r l owe s t emittance and highest energy gain for an electron at the gun exit:

!2!"0

"

#$

%

&'sin("0 ) =

12#

!th !Ea"1/2

!th

Q4!"0# x# y


Characteristics v  Coaxial coupling (e.g. Pitz-like) v  Axisymmetric: elimination of high-order mode

field components v  Elliptical irises to decrease the surface electric

field v  Single-feed (WR284 waveguide) v  Transition from rectangular waveguide to coax

through a door-knob type adapter

Surface model from HFSS

RF input power

1.6 cell RF gun

Door-‐knob adapter

Innovations v  Higher electric field at the cathode (up to 160

MV/m) v  Possibility to easily run very low charge (≤1pC)

and beams with very small transverse size (25µs for Galaxie)

The “SUPER GUN” - 3D model

Possible issues v  Multipacting (coaxial coupler can be made out

of a material with very low secondary electron yield)

v  Breakdowns (design with no electric field hot spots; experience in surface handling: Fermi II gun; High-gradient structure tested at Livermore)


v  Emax on surface=150MV/m RF Pulsed heating<50 °C v  The coupling coefficient β is adjustable by moving the location of the coax with respect to the gun cells

f = 2.85672 GHz Δf = 15MHz R = 70MΩ/m reff = 41.5MΩ/m Q0 = 16,000 Epeak = 160MV/m @ 24MW input RF power, 1μs pulse

Electric field Magnejc field

Surface model of the SuperGun, from HFSS

RF parameters


0 1 2 3 4 5 60

40

80

120

160

200

time (microseconds)

•  Assume RF pulse = 1 microsecond •  The optimum beta 2.6 for a max on-axis E-field

of 160M/m •  Short pulse in order to decrease the breakdown

rate

βopt=2.6 E0=160 MV/m

Field filling time tF= 2*Q0/[(1+β)*ω] = 495 ns, assuming =2.6 and Q0=16,000

The “SUPER GUN” - Coupling


Forward (MW) Reflected (MW) Field (MV/m)

Beam dynamics simulations


v  Galaxie: we have started to set up Parmela for simulations of the beam generation and propagation of a 1pC,1ps beam from the Super Gun (S-Band) down through the emittance exchange scheme.

v  Preliminary simulations to study the emittance splitting setup have been already carried out. An X-Band gun was used (it was decided to go towards S-Band only afterwards)

k1 k2 k3 ε±

e- beam

v  Plans for running a higher charge case (1nC) are also being made. Because of the reduced vector potential value α=2.6, we expect the location of the focusing solenoid to be further away from the gun with respect to a current S-band scenario.

v  Solenoid splitting to accommodate the input RF waveguide

Input RF power

Solenoids

Photo Injector Test facility at DESY, Zeuthen site (PITZ)

>  Electron sources for FLASH and for the European XFEL

RF-gun: • L-band (1.3 GHz) normal conducting (copper) standing wave 1½-cell cavity

• Peak rf power: up to 7MW (Ez@cathode: > 60MV/m)

• 850 µs RF pulse length with a repetition rate of 10 Hz, duty cycle ~ 1%,

• Dry ice cleaning è Dark current < 50 µA at max power

Photo cathode (Cs2Te)

QE~0.5-10%

Cathode laser λ=257nm

Trains with up to 800 pulses (1MHz) at

10Hz rep.rate.

FWHM = 25 ps

edge10-90 ~ 2.2 ps

edge10-90 ~ 2 ps

birefringent shaper, 13 crystals

OSS signal (UV)

Temporal pulse shaping

FWHM ~ 11 ps

FWHM ~7 ps

FWHM ~ 17 ps

FWHM ~ 2 ps

FWHM ~ 11 ps

FWHM ~7 ps

FWHM ~ 17 ps

FWHM ~ 2 ps

Gaussian:

Flattop (nominal)

Electron bunches: • 1nC nominal charge

• ~7MeV/c max. mean momentum

• Pulse trains

Courtesy of Frank Stephan

Emittance vs. Laser Spot size for various bunch charges

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2

0.0 0.1 0.2 0.3 0.4 0.5 0.6

100%

RM

S x

y-em

ittan

ce (

mm

mra

d)

rms laser spot size (mm)

Emittance optimization in 2011 2nC, measured 1nC, meas.(0deg) 1nC, meas.(6deg) 0.25nC, meas. 0.1nC, measured 0.02nC, meas.

n  At PITZ the projected emittance is measured with a single slit scan technique. The advantage of long pulse train operation is used to maintain a high signal/noise ratio also for low bunch charges.

n  A conservative approach of calculating a real RMS emittance is applied which takes into account even the tails of the beam distribution. Therefore our emittance numbers are called „100% RMS emittance“ (è raw data = no signal cut or any fit performed). Still the results obtained are extremely good.

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

0 20 40 60 80 100

emitt

ance

(mm

-mra

d)

charge cut (%)

2 nC (0 deg) 2 nC (+6deg) 1 nC (0 deg) 1 nC (+6 deg) 0.25 nC (0 deg) 0.1 nC (0 deg) 0.02 nC (0 deg)

n  Idea: Cut low intensity region of MEASURED phase space (i.e. remove non-lasing part)

èCore Emittance for various bunch charges

An example for 1 nC:

TABLE IV. Core xy-emittance (mm mrad) measured for various charges and gun phases. Only statistical errors are shown M. Krasilnikov et al., PRST-AB 15, 100701 (2012).

Slic

e em

ittan

ce re

quire

d at

XF

EL u

ndul

ator

for 1

nC

Courtesy of Frank Stephan

30 Courtesy of Feng Zhou, SLAC

1st established laser cleaning for LCLS application: QE evolution

•  Original QE was only 5e-6 before any cleaning process

•  QE was firstly increased by 8-10 times upon the laser cleaning

•  QE was further increased by 3 times in the first 6 months following laser cleaning, and then stays at 1.1e-4 from 6th month to now, 20th months following cleaning.

QE

Gun vacuum

31

Improved emittance with spatial Gaussian-cut laser

Ø  Spatial Gaussian-cut profile has: •  saved laser power required from laser

amplifier 2-3 times •  improved emittance 30%

Courtesy of Feng Zhou, SLAC

•  March-‐April 2013: first tests with “real” Cs2Te cathodes Jay IPA -‐fdfff011

The LBNL CW NC VHF gun

750 keV with ~ 100 kW RF power

1st photo-‐emiHed beam from a “dummy” moly cathode: 10 nA

(10 fC @ 1 MHz).

Nominal operajon energy achieved.

Courtesy of Daniele FilippeHo

The PSI gun

Courtesy of A. Falone-‐J.Y Raguin

Elliptical iris – minimize surface fields Large iris thickness – mode separation Dual feed – field symmetry Racetrack shape – suppresion quads components No cathode loading hole – dark current Flat end wall – reduces laser misalignment issues Pick up – 1 for each cell Interchangeable with CTF3 gun

f0 2997.9 MHz (2998.8 MHz)

Q0 13570

Δf ~16 MHz

Rep. Rate < 400 Hz

Gradient 100 MV/m @ 20 MW

Different charges rescaling

o  Compared to the CTF3 gun with the PSI gun we gain more and more for greater charges

o  Mismatch maintained for all the configurajons below 1.1 in the central part of the bunch

o  Final beta < 70 m and |alpha| < 2

o  Well below the ablajon limit of the Cu cathode (C. Vicario -‐ private communicajon)

Q (pC) Case Projected ε (mm.mrad)

Slice ε (mm.mrad)

CDR projected ε (mm.mrad)

CDR slice ε (mm.mrad)

Laser power (compared to CDR 200 pC case)

10 Opt_I 0.090 0.076 0.096 0.080 Px1.9

50 Rescaling 0.16 0.135

0.174 0.160 Px2.0

Opt_I 0.16 0.135 Px2.0

100

Rescaling 0.21 0.18

0.233 0.230

Px1.89

Opt_I 0.21 0.18 Px1.90

Opt_II 0.20 0.16 Px3.0

Opt_III 0.20 0.16 Px3.0

200 Opt_23 0.25 0.21 0.35 0.32 Px1.0

A0PI: ellipsoidal-‐bunch generaAon from Cs2Te •  Ellipsoidal bunches have linear

space-‐charge field •  Short-‐pulse laser (110 fs rms)

illuminate cathode •  Noveljes:

–  L-‐band gun (35 MV/m) –  Semiconductor cathode –  20x higher charge than in previous experiments

Courtesy of Philippe Piot 35

Sub-110 fs

laser system

CsTe cathode

“0 pC”

z (m)

time

x

P. Piot, et al, PRSTAB 16, 010102 (2013)

130, 280, 460, 700 pC

current

time

L-band rf gun

electron bunch

bunc

h le

ngth

(mm

)

Pop

ulat

ion

time (ps)

laser

booster

gun

Nanopatterned Cathodes Another line of research has been the exploration of surface plasmon a s s i s t e d p h o t o e m i s s i o n f ro m nanostructured cathodes. First tests showed a charge yield increase of more than two order of magnitude from the nanopatterned surface when compared with the flat case.

Ultra-low charge beams and nm-emittance measurements Ø Blow-out regime is based on pancake aspect ratio at cathode followed by longitudinal space charge dominated expansion. Ø Nearly ideal uniformly filled ellipsoidal distribution can also be obtained from an initial cigar aspect ratio and transverse space charge expansion •  Shape temporal profile of laser pulse •  Obtain sub-50 nm transverse emittance Ø  Experimental tests using <30 um laser spot on cathode. Ø  Beam is round and well-behaved. Ø  Low charge (0.1-1 pC)

(courtesy of Pietro Musumeci, Phys. Rev. ST Accel. Beams 15, 090702 (2012))

PEGASUS LAB - UCLA

New SPARC clamped gun The new SPARC RF GUN is a 1.6 cell gun and, with respect to the installed BNL/SLAC/UCLA type gun, has the following improvements: 1)  the iris profile has an elliptical shape and a larger

aperture to: -reduce the peak surface electric field; -increase the frequency separation between the two RF gun modes (up to 38 MHz) -increase the pumping speed on the half-cell;

2)  the tuning is realized by deformation tuners;

3)  the coupling hole has been strongly rounded to reduce the peak surface magnetic field and, therefore, the pulsed heating;

4)  The coupling coefficient has been increased form 1 to 2 to allow operation with shorter RF pulses (<1µs) thus reducing the BDR;

5)  the cooling pipes have been improved and increased in number to guarantee a better gun temperature uniformity and available operation up to 100 Hz;

6)  the structure has been realized without brazing but using special gaskets in order to:

-simplify the fabrication -reduce the cost -reach (because of the hard copper not brazed) higher accelerating field with lower BDR.

The gun has been realized and it is now under low power testing. High power test will be done after low power test.

Parameters Value

fres 2.856 GHz

Q0 15000

Esurf_peak_iris/Ecathode 0.85

Coupling β 2

Pin_peak@Ecathode=120MV/m 12 MW

Filling time τF 835 ns

Frequency sep. 0 and π-mode 38 MHz

Pulsed heating @ 120 MV/m (1 µs RF pulse) <40 °C

Courtesy of D. Alesini

X-‐Band Photoinjector at SLAC

5.5 cell X-‐Band gun

1st e-‐beam July30th 2012

•  e-‐beam out of gun E~ 7.5MeV (VRF,peak~ 200MV/m) •  dark current acceptable •  e-‐beam at 70 MeV ater 1.05 m linac •  charge up to 40pC , QE just in 1e-‐5 range •  bunch length measured ~ 250 fs rms for 20pC •  energy spread rms 15 keV at 70 MeV (15 pC) •  emiHances < 3 mm-‐mrad (but very preliminary

opjmizajon)

XTA located in NLCTA at SLAC

Plot of Emittances from different RF Guns


Plot of Emittances from different RF Guns


Below 2pC

Ultra-low emittance measurements

Pegasus-UCLA


Conclusions

v Radio-Frequency RF Guns are by far the most efficient device allowing the generation of high current, low emittance electron beams

v The new RF gun for the Fermi FEL at Sincrotrone Trieste was successfully installed and conditioned at high-power (11MW, 1.5µs and 50Hz)

v  Fermi II RF Gun is an improved and more compact version of the current gun (Fermi Gun 1.5 mm-mrad) and it will hopefully allow to achieve much lower emittance values. First beam at the end of April 2013.

v The design of the “Super Gun” for the GALAXIE project represents a break-through in the field of

RF multi-cell Guns à new materials, material technology (e.g. Free Form Fabrication?), surface handling, laser shaping…

v  Point of interest for many Labs at the moment à beam charge from 40pC to 300pC

v Ultra-low charge (<1pC) à ; is it a main step to go towards the 5th generation light source?


Be !Q"2/3 to Q"4/3

Thanks for your attention!


luigifaillacehbeb13

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