ENEA DS3 PARTICIPATION

EUROFEL PROJECT

Oscillator 80 MHz

Reg. Amplifier

Multipass Amplifier

Reg. Amplifier

Harmonic GenerationCathode

Basic Considerations

Basic Considerations

•In the SPARC experiment the electron beam is 10 ps long and has a flat-top profile•The seed radiation is very short, about 100 fs•A jitter of +/- 1 ps is tolerable in SPARC, but in future, will be compressed down to 1 ps time range, thus the jitter requirements will get tighter.

In order to evaluate the synchronization process in seeded high gain FEL, a measuring technique will be developed exploiting the properties of the radiation generated in the magnetic undulator.

A second technique will be studied in order to measure the jitter of both the electron beam and the UV seed generated by the high harmonic generation process in gas or crystals.

In order to perform both measurements a delay line system is needed between the electron beam and the UV seed. The delay adjustment allows the overlapping between the electron bunch and the radiation seed at the undulator entrance.

Activities

7 ns

1 nsCrystal/GasHarmonic Generator

Delay Line

Reg. AmplifierTi:Sa @ 10 Hz

The Regenerative Amplifier is excited at 1 KHz but the Pockel’s cells are enabled by the e-gun trigger at 10 Hz. The Amplifier cavity round trip is about 7 ns that thus correspond to the uncertainty exit time for the amplified Ti:Sa pulse.

Undulator length for the power measure must be chosen in order to maximize the differences between the SASE process and the seeding process.

Synchronization Measurements

0 2 4 6 8 10 12 14 160

1 107

2 107

3 107

4 107

Z (m)

160 nm – 20 kW

0 2 4 6 8 10 12 14 160

1 107

2 107

3 107

4 107

5 107

Z (m)

160 nm – 5 MW

A perfect synchronization is realized when a maximum power for the radiation generated at the undulator exit is recorded.

StreakCamera

For the jitter measurement it is necessary to desynchronize the seed respect to the electron beam and then analyze the envelope of the longitudinal width, of both the signals, during a long time measurement.

Jitter Measurements I

Type

Number

Features Spectral Response Characteristics

Sweep Unit

Temporal Resolution

C7700 High dynamic range

200 to 850 nm

300 to 1060 nm

Built in <5 ps

C6138

FESCA 200

The fastest temporal resolution streak camera

280 to 850 nm Built in

< 300 fs (typically 200 fs)

C2830 Low cost 200 to 850 nm M2547

M2548

<10 ps

< 100 ps

C4187 Large photocathode

200 to 850 nm

300 to 1600 nm

M4190

M4191

<10 ps

< 250 ps

Hamamatsu Streak cameras

Type

Number

Features Spectral Response Characteristics

Sweep Unit

Temporal Resolution

C5680 High repetition: Max 165 MHz

115 to 850 nm

300 to 1600 nm

200 to 900 nm

M5676

M5677

M5675

< 2 ps

< 50 ps

< 2 ps

C6860 High repetition: Max 100 MHz

200 to 850 nm

300 to 1600 nm

M6861

M6863

< 500 fs

< 50 ps

C4575-01 For X-rays 10 eV to 10 KeV Built in <2 ps (1 ps typically)

C5680-06 For X-rays 10 eV to 10 KeV Built in <5 ps

C2590-01 For X-rays 10 eV to 10 KeV Built in < 20 ps

Non Linear Medium

Time Profile Spatial Profile

Jitter Measurements II

Undulator

Experimental Setup

Undulator

Quadrupol

Diagnostics Chamber

CCD CamerasAnd Detectors

Streak Camera

Optical Line in the SPARC Hall

Sala SPARC Sala Macchine Inferiore