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ABI Workshop on Emittance measurement, Bad Kreuznach, December, 11-12th 2008. The problematic of EMITTANCE MEASUREMENT for IFMIF-EVEDA. P. A. Phi NGHIEM Contributors: N. CHAUVIN, C. OLIVER, A. MOSNIER, D. URIOT. ISSUES for E < 5 MeV E > 5 MeV. The IFMIF-EVEDA project.
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ABI Workshop on Emittance measurement, Bad Kreuznach, December, 11-12th 2008 The problematic ofEMITTANCE MEASUREMENTfor IFMIF-EVEDA P. A. Phi NGHIEM Contributors: N. CHAUVIN, C. OLIVER, A. MOSNIER, D. URIOT ISSUES for E < 5 MeV E > 5 MeV
The IFMIF-EVEDA project International Fusion Materials Irradiation Facility 5.0 MW Engineering Validation Engineering Design Activity 1.1 MW Being constructed IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
600 mm 300 mm 550 mm 300 mm 300 mm RFQ ECR Source Solenoid Solenoid Extraction ISSUES at E < 5 MeV: important losses • Challenging point: to reach the required beam intensity 125 mA LEBT Extraction Focusing and Injection Focusing and Acceleration NEED to MEASURE EMITTANCE and TWISS Parameters IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
SIMULATIONS At the RFQ entrance: Bad s.c. compensation No regular distribution IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
STRONG SPACE CHARGE Strong non-linear calculations ⇒Simulations can be trusted ? ⇒NEED MEASUREMENTS High Compactness ⇒NO ROOM for DIAGNOSTICS at the RFQ entrance ≠ Only emittance measurements between the two solenoids or at commissioning, RFQ not yet installed see C. OLIVER et al. For online tuning: only by maximising the RFQ current transmission But Emittance and Twiss parameter measurements would be very helpful ! IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
ISSUES at E > 5 MeV: micro losses • THE challenging point: • Combination of - very strong beam power • - hands-on maintenance 1W/m 125 mA NEED to MEASURE EMITTANCE and MICRO LOSSES IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
TUNE DEPRESSION EMITTANCE GROWTH IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
Transverse and Longitudinal RMS Values External part of the beam : 10-1 - 10-6 IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
VERY HIGH POWER Micro Losses, Halo 10-6 ⇒Simulations can be trusted ? ⇒MEASUREMENTS of Micro Losses and Bunch Length are essential of Transverse Emittance is very helpful High Compactness ⇒NO ROOM for DIAGNOSTICS in the HWR-Linac ≠ see C. OLIVER et al. Only emittance measurements after the HWR-Linac, in the HEBT For online tuning: only micro loss devices (thermocouples ?) and Beam Loss Monitors (ionisation chamber) IFMIF-EVEDA - Accelerator System Group – Beam Dynamics
Measuring mLOSSES in the HWR-solenoids ++ advantages -- drawbacks 4 possible solutions 1. Measure heat deposited on the solenoid chamber with thermocouples: 1/10 W in ~ few seconds ++ simple, cheap -- sensitivity, speed see J. Marroncle 2. Measure intensity deposited on the existing BPMs: ~10 nA ++ existing -- sensitivity 3. Measure intensity deposited on the solenoid vacuum chamber: ~10 nA ++ sensitivity, speed -- isolate the chamber portion 4. Use quadrupole with BPM inside instead of solenoid ++ feasible -- complex, expensive see F. Toral IFMIF-EVEDA - Accelerator System Group – Beam Dynamics