PHIN

1. PHIN R. Losito CERN – AB/ATB 05/09/2005

2. WP1: Management • Website created • Maintainance and upgrade

3. WP2: Charge Production • 3 GHz RF Gun • High efficiency photocathode comparison • Intermediate report done • Final report: reported to end of 2006 (no news from Twente..). • Photocathode preparation equipment construction • Under way, delays due to problems in refurbishing certain components, production of photocathodes should restart in November at CERN. • Photocathode 3 GHz high field R&D • Dark current measurements, thin fim adherence under high field etc.. • Will start after arrival of the RF Gun (December/January?) • Milestone will probably slip by some months

4. WP2: Charge Production • Photocathodes for SC Cavity • Photocathode preparation equipment ready (31/03/05)

5. FZR SRF Photogun – Cathode Preparation The photocathode preparation system was completely assembled and its function was tested. It contains two pairs of evaporators for Te and Cs, the holder and heater for the cathode with temperature measurement, a motor driven shutter, a measurement aperture for photo current, and two deposition rate monitors allowing co-evaporation, and is equipped with a 262 nm, 10 mW laser system. The computer control system (electronics and software) is ready. At present, the system is disassembled and the parts are being cleaned. After that, the system will be assembled again in the clean room.

6. WP2: Charge Production • Photocathodes for SC Cavity • Photocathode preparation equipment ready (31/03/05) • The new preparation equipment was installed and tested. At present it is being cleaned for installation in the clean room. • Photocathodes tests • Will start when material ready.

7. WP2: Charge Production • Laser Driven Plasma source • No fresh news from LOA …..

8. WP3, T1: LASER • Laser for the CTF3 Photoinjector: • All the milestones have shifted by ~6 months due to the late arrival of funding and long procurement delays due to specificity of the material. • An important deliverable reached is the laser oscillator: Built by HighQLaser (Austria), it is the first of his kind with • rep rate of 1.5 Ghz • rms pulse lenght < 10ps • Jitter < 1 ps • Amplitude stability < 0.2 %

9. WP3, T1: Oscillator and preamplifier The results of the acceptance tests: The oscillator and preamplifier are now working to specification at RAL The additional preamplifier has delivered the required power The improved timing jitter seems to be due to low environmental noise at RAL Anomalous photodiode measurements at CERN have been resolved

10. WP3,T1: Amplifier procurement Amplifier 1 assembly and testing will begin in September Amplifier 2 assembly and testing will begin in November

11. WP3, T1: Updated layout of the system 350 cm HighQ oscillator Coding 1st amplifier FOM system Feedback stabilisation HighQ amplifier Faraday isolator Diagnostics Delay line Beam size provided for 1st amplifier Beam size provided for 2nd amplifier Pockels cell(s) for generating 1.5 us train Laser beam to cathode Beam size provided for SHG Beam size provided for FHG 150 cm Diagn. Diagn. Thermal lensing compensation 2nd amplifier Table at RAL Breadboard Amplifier beam heights ~ 12 cm : alignment check camera Table at CERN : calibrated PD for power monitoring • Recent modifications include final layout of HighQ system, extra diagnostics and “inversion” of the overall scheme to improve stability of beam delivery to the accelerator vault • A timing and control system, compatible with the CERN architecture, has been specified

12. WP3, T1: Time & Amplitude Structuring PULSE SLICING • Needs two large-aperture Pockels cells (single-pulse and 1.54ms train) to handle high average power after Amplifier 2 • Current design includes programmable corrector to reduce systematic pulse amplitude variations to <0.1% RMS • System is commercially available AMPLITUDE STABILISATION • If the intrinsic amplitude noise is low then a low-retardance Pockels cell will be adequate, requiring low drive voltage compatible with fast electronic amplifiers • Performance will be dominated by the sensor and the feedback control electronics • Sensor and cell are commercially available but FC electronics need specialist design PULSE CODING • Requirement for a 7 MHz, multi-kV, drive waveform with <300ps switching time and better than 1% amplitude control makes a system based on a Pockels cell unviable • The alternative is a fibre-optic (FO) modulator system placed after the oscillator where the average power is low • The >10dB losses of an FO system will require more gain from the preamplifier • The FO system is commercially available and the preamplifier’s manufacturer can increase its gain, but this will involve some delay, best left to the end of the program

13. WP3, T1: Fast pockels cell drivers New devices developed by the Ioffe Physical-Technical Institute of Russia Academy of Science in St. Petersburg. They are based on a new physical phenomenon: the elctrone-hole plasma supergeneration in solid state. This permits to have high operating voltage up to 5kV and the turn-on time less than 1 ns. The DSRD are diodes characterized by fast voltage restoration that assures low commutation jitter, unlimited life time, repetition rate that can be as high as megahertz and opening times can be less than 1 ns with 100 A current. New Fast Ionization Devices (FID) and Drift Step Recovery Diodes (DSRD) Customization of standard product. E.g:

14. WP3, T1: (LASER) Timescales and deliverables

15. WP3, T2: Shaping of the UV laser pulse UV time profile measured using a multishot cross-correlator with 200 fs resolution. It is possible obtain rise-time < 1 ps and ripples < 30%

16. High energy UV @ 10 Hz 2856 MHz cavity laser pulses phase [deg] WP3, T3 : Low rep rate synchronization tests at LNF On time scale of few minutes (enough to adjust the RF) the phase jitter is within σRMS0.63 deg [0.61 ps]. Further characterizations are foreseen.

17. WP4, T1: FZR SRF Photogun Superconducting Nb cavities: The two cavities were delivered by ACCEL in March 2005. One is made of high-quality Nb RRR 300 for use in the gun, one of Nb RRR 40 for tests (instead of a Cu model, which additionally allows to check e-beam welding, warm tuning, and chemical treatment etc.)

18. WP4, T1:FZR SRF Photogun – RF Measurement and Tuning 3D-CAD-Model of the tuning machine used for warm tuning (to push and pull each cell to the right frequencies). The special cavity shape required to build such a machine at FZR. 1: Sensors-vertical position, 2: Sensors horizontal Pos., 3: DC-Motor (bead pull drive), 4: Stepper motor (vertical pos.), 5: Motor control box, 6: Sensor hardware, PC-controlled bead pull measuring device (principle) built at FZR in 2005.

19. WP4, T1: FZR SRF Photogun – Warm Tuning Field profiles from bead pull measurements. Before chemical treatment, warm tuning of the cavities has been carried out in order to obtain the right frequency and the designed field profile (equal amplitudes in the three TESLA cells and 64% in the half-cell). Photograph of the cavity tuning machine with integrated bead pull measuring device.

20. WP4, T1:FZR SRF Photogun – Cathode Cooling System The test of the cathode cooling system has been succeeded. In the SRF gun, the normal conducting cathode is inside the SC cavity. With the test was proofed whether the cathode heat load (from rf field) will be transported into the liquid N2 cooler. It was found that the cooling system works well and only a small amount of the heat (some mW) will be transferred to the SC cavity. Cathode with heater Cooling body Liquid nitrogen reservoir The cathode cooling system mounted on the test bench flange. The rf heat load is simulated by an electrical heater (10 – 50 W).

21. WP4, T1: FZR SRF Photogun – Project Status CAVITY: Two Nb cavities (NbRRR300 + RRR40) have been delivered. Rf-tests and warm tuning has been performed at FZR. Chemical treatment will now start at DESY. CRYOMODULE: Most of the main components (vacuum vessel, 80 K cryo-shield, magnetic shield, support frame, rf coupler, tuner, cathode cooler, cathode transfer system) have been delivered. Cathode cooler test has succeeded. The tuner test is under way. He transfer line is ordered. PHOTO CATHODES: The new preparation equipment was installed and tested. At present, it is being cleaned for installation in the clean room. LASER: The upgrade of the driver laser system is under way (MBI). DIAGNOSTICS: a diagnostics beam line is designed. The realization has started (BESSY).

22. WP4, T1: 3GHz RF GUN • WP4 RF GUNS STATUS • 1st RF Gun construction • After many tries of the manufacturer to do a elliptical shape, a compromise was done: irises are done in 12 facets and it meets the specifications. ordered in the end of April, 4 months of delay, delivery in beginning of September • Measurements and mechanical adjustments are planned for one month, delivery of the gun by the end of December if everything goes well • RF gun at LAL • Laser was ordered to Opton Laser in July, delivery in 4 months • NEPAL room • Shielding • Other Radio-protection study is under way to reduce the cost

23. WP4, T1: Spectrometer for e-beam • No News from LOA

24. Conclusions • Work generally on track for CTF3 photoinjector, Photoinjector at LAL, SC RF Gun and studies of pulse shaping in Frascati. • Due to holidays and to injury of Andrea, difficult to get information about Twente, INFN – Mi, Loa. • Should be addressed at the next collaboration meeting.