SSSEPB working group discussion topics Gabriel Marcus, on behalf of the organizing committee August 3-7, 2015

SSSEPB working group discussion topics

Gabriel Marcus, on behalf of the organizing committee

August 3-7, 2015

2

Working groups

• 1.5 hours at the end of each day will be dedicated to

working groups

• ~ 4 students per group

• Choose a topic relevant to the SSSEPB material

• A list of suggested references will be provided

• Prepare a short (15 – 20 minute) presentation on the

chosen topic to be given by one group member on Friday

3

10 groups

number name

1 A AbuAli D Khan G WangZ Wang

L Gupta 7

2 M Hamamou S Li

3 E Curry J MacArthur Y Xu K LarsenA Hanuka

13

4 D Cesar A Hanna M Croia O Mohsen 14

5 C Emma J Franssen MK Weikum X Nie 3

6 C-K Huang D Yang A Halavanau P Niknejadi 12

7 N Sudar Q Gao A Vrielink ZH Guo 6

8 E Welch S Mohamed L Zeng W Qin 16

9 X Xu T Rui G Campogiani M Sangroula 9

10 I Ali L Zheng J Scifo M Marongiu 4

4

List of topics

Electron sources

Thermal emittance of conventional cathodes;

Novel electron sources (nanotip, ultracold beam

source);

Beam dynamics

Blowout regime for generation of ellipsoidal

beam.

Emittance exchange;

Slice energy spread growth in photoinjectors;

Coherent synchrotron radiation in magnetic

bunch compressors.

Application of FELs

Coherent diffraction imaging.

Measuring e-beam and photon beam

Transverse coherence;

Laser based methods to measure ultrashort

electron beam temporal profile;

Measure ultrashort x-ray profile in FELs;

Enhancing FEL capabilities

Laser heater;

Temporal coherence;

Self-seeding;

Generation of attosecond x-ray pulse.

Plasma accelerator

External injection;

Plasma accelerator based light source.

SSSEPB Discussion Topics

Other novel concepts

Inverse Compton scattering based x-ray light

source;

Inverse free-electron laser accelerator;

5

1. Thermal emittance of conventional cathodes

Thermal emittance sets the lower limit

References

D. Dowell and J. Schmerge, Phys. Rev. ST Accel.

Beams 12, 074201 (2009).

J. E. Clendenin et al., SLAC-PUB-8284, 1999.

C. P. Hauri et al., Phys. Rev. Lett. 104, 234802 (2010).

H. Qian et al., Phys. Rev. ST Accel. Beams 15, 040102

(2012).SSSEPB Discussion Topics

Gun Linac Bunch compressor Linac Undulator

emittance

Understand the emission process What determines thermal emittance? How to reduce thermal emittance?

cathode

laser

photoelectrons

space charge

coherent synchrotron radiation

z

x-ray

thermal emittance

6

2. Novel electron sources

References

P. Hommelhoff et al., Phys. Rev. Lett. 96, 077401 (2006)

B. J. Claessens et al., Phys. Rev. Lett. 95, 164801 (2005)

A. J. McCulloch et al., Nature Physics 7, 785 (2011)

R.K. Li et al., Phys. Rev. Lett. 110, 074801 (2013)

A.Polyakov et al., Phys. Rev. Lett. 110, 076802 (2013)


Understand the physics Advantages and disadvantages Challenges

Nanotip cathode (field emission array)

Nanostructured cathode

Ultracold electron source

7

3. Blowout regime for generation of ellipsoidal beam

References

O.J. Luiten et al., Phys. Rev. Lett. 93, 094802 (2004)

P. Musumeci et al., Phys. Rev. Lett. 100, 244801 (2008)

B. O’Shea et al., Phys. Rev. ST Accel. Beams 14, 012801 (2011)

P. Piot et al., Phys. Rev. ST Accel. Beams 16, 010102 (2013)

Y. Li and J. Lewellen, Phys. Rev. Lett. 100, 074801 (2008)


Understand the physics Advantages and disadvantages Sensitivity to laser parameters and charge

Space charge induced emittance growth Experimental realization

Recipes to ellipsoidal beam

3-D laser pulse shaping

Blowout regime: an ultrashort laser with

an appropriate transverse profile is used

to generate a short beam that

automatically evolves to an ellipsoidal

beam through longitudinal expansion

8

4. Emittance exchange

References

M. Cornacchia and P. Emma, Phys. Rev. ST Accel. Beams 5, 084001

(2002).

P. Emma, Z. Huang, K.-J. Kim, and P. Piot, Phys. Rev. ST Accel.

Beams 9, 100702 (2006).

Y.-E Sun et al., Phys. Rev. Lett. 105, 234801 (2010).

D. Xiang and A. Chao, Phys. Rev. ST Accel. Beams 14, 114001

(2011).

D. Xiang, SLAC-PUB-15196, (2012).SSSEPB Discussion Topics

Understand the physics Advantages and disadvantages Applications

The ability to tailor a beam’s 6D distribution is

one of the ultimate goals in accelerator physics. Beam line

11 12 13 14 0

21 22 23 24 0

31 32 33 34 0

41 42 43 44 0

''

R R R R xx

R R R R xx

R R R R zz

R R R R

0 0

0 00 0

0 0

Applications in shaping e-beamUse masks to shape beam x-distribution,

and then use EEX to shape z-distribution.

Varian's collimator

‘Beam by design’

9

5. Slice energy spread growth in a photoinjector

References

J. T. Moody et al., Phys. Rev. ST Accel. Beams 12, 070704

(2009)

Z. Huang et al., Proceedings of PAC2005, p3570, 2005.

M. Huning and H. Schlarb, Proceedings of PAC03, p2074, 2003.

Z. Huang, SLAC-TN-05-026, 2005.

G. Stupakov and Z. Huang, Phys. Rev. ST Accel. Beams 11,

014401 (2008).


Understand the cause of slice energy

spread growth How to reduce slice energy spread

Beam slice energy spread quickly grows from ~eV to ~keV in a photoinjector

Possible causes

RF field (Ez depends on x and y)

Longitudinal space charge field

Intrabeam scattering

10

6. Coherent synchrotron radiation in magnetic bunch compressors

References

E. Saldin et al., Nuclear Instruments and Methods in Physics

Research Section A, 398, 373 (1997).

H. Braun et al., Phys. Rev. ST Accel. Beams 3, 124402 (2000).

M. Borland, Phys. Rev. ST Accel. Beams 4, 070701 (2001).

K. Bane et al., Phys. Rev. ST Accel. Beams 12, 030704 (2009).

LCLS Conceptual Design Report, Chapter 7, 2002.


Understand the scaling of CSR effects Understand how CSR increases bend plane projected emittance Understand how to properly design a bunch compressor to

mitigate CSR induced emittance growth

CSR increases beam emittance and energy spread, and reduces peak current

11

7. Laser heater

References

Z. Huang et al., Phys. Rev. ST Accel. Beams 7, 074401 (2004).

J. Wu et al., SLAC-PUB-10430, 2004.

Z. Huang et al., Phys. Rev. ST Accel. Beams 13, 020703 (2010).

C. Behrens, Z. Huang and D. Xiang, Phys. Rev. ST Accel.

Beams 15, 022802 (2012).


Understand microbunching instability How laser heater works Reversible heater

Microbunching instability (uBI)SMALL initial modulation gets amplified and leads to SERIOUS degradations to beam quality

Without laser heater

injector undulator

With laser heater

injector undulator

undulator

laser

beam

A laser heater increases beam slice

energy spread to suppress uBI

12

8. Temporal coherence of SASE FELs

References

R. Bonifacio, L. De Salvo, P. Pierini, N. Piovella, and C. Pellegrini, Phys. Rev.

Lett. 73, 70 (1994).

E. Saldin, E. Schneidmiller, and M. Yurkov, Optics Communications 148, 383

(1998).

J. Wu, C. Pellegrini, and A. Marinelli, Proceedings of FEL12, 2012.

D. Xiang, Y. Ding, Z. Huang and H. Deng, Phys. Rev. ST Accel. Beams 16,

010703 (2013).

B. W. J. McNeil,, N. R. Thompson, and D. J. Dunning, Phys. Rev. Lett. 110,

134802 (2013).


Understand statistic properties of radiation

produced in a SASE FEL Various ways to improve temporal coherence

and their pros and cons

Self-amplified spontaneous emission (SASE) FELs start from shot noiseIn SASE FELs, radiation overtakes e-beam by one radiation wavelength λ per undulator period

Radiation fields with distance larger than Nλ evolve independently and therefore are

uncorrelated in phase

N N N

SASE FEL power profile

iSASE, pSASE, HB-SASE to improve

temporal coherence

e-beam

13

9. Self-seeding in SASE FELs

References

J. Feldhaus et al., Opt. Communications, 140, 341 (1997).

G. Geloni, V. Kocharyan, and E. Saldin, Journal of Modern Optics, 58,

1391 (2011).

Y. Ding, Z. Huang and R. Ruth, Phys. Rev. ST Accel. Beams 13,

060703 (2010).

J. Amann et al., Nature Photonics 6, 693 (2012).


Understand the physics of various self-

seeding configurations Advantages and disadvantages How to improve the power stability of a self-

seeded SASE FEL

Introducing a seed with excellent temporal coherence to dominate over shot

noise allows generation of fully coherent x-rays in a SASE FEL

monochromator

SASE

amplify to GW

14

10. Generation of attosecond x-ray pulses in FELs

References

Y. Ding et al., Phys. Rev. Lett. 102, 254801 (2009).

J. Rosenzweig et al., Nucl. Instrum. Methods Phys. Res., Sect. A 593,

39 (2008).

P. Emma et al., Phys. Rev. Lett. 92, 074801 (2004).

I. P. S. Martin and R. Bartolini, Phys. Rev. ST Accel. Beams 14,

030702 (2011).


Understand the physics Advantages and disadvantages

Faster pulses are needed to explore the dynamics of fast events

Compress a low charge beam

Using a few-cycle laser

Slotted foil in a chicane

15

11. Transverse coherence

References

Vartanyants et al., Phys. Rev. Lett. 107, 144801 (2011)

Z. Huang and K.-J. Kim, Phys. Rev. ST Accel. Beams 10,

034801 (2007)

A. Singer et al., Optics Express 20, 17480 (2012)

M.D. Alaimo et al., Phys. Rev. Lett. 103, 194805 (2009)


Why FEL has good transverse coherence How to measure transverse coherence

Coherence is a degree of predictability

What do they need? -Coherence!

FEL has good transverse coherence

Young’s double slit

zGain guiding in FEL

pinhole for synchrotron radiation

16

12. Laser based methods to measure ultrashort e-beam

References

E. Saldin et al., Nuclear Instruments and Methods in Physics

Research Section A, 539, 499 (2005).

G. Andonian et al., Phys. Rev. ST Accel. Beams 14, 072802

(2011).

Y. Ding et al., Proceedings of FEL2011, p431, Shanghai, 2011.


The wavelength of optical laser may be a perfect ruler to measure e-beam

Optical replica synthesizer

Optical oscilloscope

Optical streaking


undulator

x

TCAVe-

17

13. Measure ultrashort x-ray pulses in FELs

References

U. Frühling, Nature photonics, 3, 523 - 528 (2009).

Y. Ding et al., Phys. Rev. ST Accel. Beams 14, 120701

(2011).

Y. Inubushi et al., Phys. Rev. Lett. 109, 144801 (2012).

Y. Ding et al., Phys. Rev. Lett. 109, 254802 (2012).


Understand the physics Advantages and disadvantages Challenges

THz streaking

Correlation functions

Measure what x-ray does to e-beam

correlation in time correlation in frequency

18

14. External injection in plasma accelerator

References

E. Esarey, C. P. Schroeder, and W. P. Leemans, Review of Modern Physics,

81, 1229 (2009)

H. Suk, N. Barov, J. B. Rosenzweig, and E. Esarey, Phys. Rev. Lett. 86, 1011

(2001)

J. Faure et al., Nature 444, 737, 2006

A. Pak et al., Phys. Rev. Lett. 104, 025003 (2010).

B. Hidding et al., Phys. Rev. Lett. 108, 035001 (2012).


Ultrashort laser pulse used to optically trigger the injection of electrons

Self injection

Plasma photocathode

Colliding pulse injection


19

15. Plasma accelerator based light source

References

M. Fuchs et al., Nat. Phys. 5, 826 (2009).

A. R. Maier et al., Phys. Rev. X.2, 031019 (2012).

Z. Huang, Y. Ding, C. Schroeder, Phys. Rev. Lett. 109, 204801

(2012).

L. Chen et al., Nature Scientific Reports 3, 1912 (2013).

S. Corde et al., Rev. Mod. Phys. 85, 1 (2013).


Cheaper and more compact

Undulator radiation

Realizing FEL gain

Betatron radiation

Understand the physics Understand the challenges

20

16. Coherent diffraction imaging

References

J. Zuo et al., Science 300, 1419 (2003).

H. Chapman et al., Nature physics, 2, 839 (2006).

H. Chapman and K. Nugent, Nature Photonics 4,833 (2010).

H. Chapman et al., Nature, 470, 73 (2011).

M. Seibert et al., Nature, 470, 78 (2011).


‘lensless’ technique for 3D structure determination

How to form an image?

Diffraction before destruction

Replace the lens with software

Understand the physics Understand source requirements Applications and challenges

21

17. Inverse Compton scattering (ICS) based x-ray source

References

I.V. Pogorelsky et al., Phys. Rev. ST Accel. Beams 3, 090702

(2000).

F. V. Hartemann et al., Phys. Rev. ST Accel. Beams 8, 100702

(2005).

A. Bacci et al., Phys. Rev. ST Accel. Beams 9, 060704 (2006).

Z. Huang and R. Ruth, Phys. Rev. Lett. 80, 976 (1998).


Using lasers as undulators for generation of short-wavelength radiation

Why and how

Gain in ICS

Increase number of photons / second

Understand the physics How to increase photons per second? How to get gain?

e-beam

laser

22

18. Inverse free-electron laser accelerator

References

E. Courant, C. Pellegrini and W. Zakowicz, Phys. Rev. A 32, 2813

(1985).

W. D. Kimura et al., Phys. Rev. Lett. 86, 4041 (2001).

J. P. Duris, P. Musumeci, and R. K. Li, Phys. Rev. ST Accel.

Beams 15, 061301 (2012).

M. Dunning et al., Phys. Rev. Lett. 110, 244801 (2013).


Using lasers to boost electron beam energy in an undulator

FEL and inverse FEL

Cascading in inverse FELs

~GV/m gradient with optimizations

Understand the physics How to improve beam quality Applications and limitations

In an FEL, the energy of electron beam is

transferred to the radiation field; in an inverse FEL,

the energy of radiation (typically a high power

laser) is transferred to electron beam

Laser waist size, undulator tapering

23

SSSEPB discussion sessions


To-do-list:

- Each group will choose one topic from the list (Monday)- Read papers and have discussions with group members in the

afternoon sessions (Monday – Thursday)- Each group have one representative give a 15 – 20 minute talk

(~15 slides) (Friday morning)- Get references from me or from other tutors

Have a fun and productive

week at SLAC!

Documents

SSSEPB working group discussion topics Gabriel Marcus, on behalf of the organizing committee August 3-7, 2015