1. 3 MeV Measurements at Lianc4 1 Veliko Dimov (for the source and linac team) (J-B Lallement, J. Lettry, A. Lombardi, D. Fink)

2. Status of the Linac4 beam commissioning Commissioning up to 12 MeV (end of 1 st DTL tank) was completed (end of 2014). 2 nd and 3 rd DTL tanks were installed in the tunnel. Next stage is 50MeV beam commissioning. Short period of measurements at 3MeV. To check the performance of the RFQ with the new H- source (beam current 20mA  50mA) To see what beam we expect for the 50MeV beam commissioning stage. 2

3. Beam Current Transformers (BCT) for Transmission measurements Dump Chopper Measurements at 3 MeV 3 Faraday Cup Wire scanners Transmission through the RFQ Different LEBT pressure levels Different Source settings Beam current at the LEBT (Faraday cup and BCT) Different source settings by varying the first solenoid Wire Scanner measurements at 3MeV.

4. We have 30mA beam at 3 MeV Ion Source output beam current: 50mA 4

5. Transmission Through the RFQ 5 37 mA (before the RFQ) 42 mA (before the RFQ) What comes out of the RFQ is the same (30mA): input emittance is bigger than the RFQ acceptance!!!

6. Estimating the emittance by comparing with the simulations. 6 The transmission depends on the beam current and emittance. 37 mA (before the RFQ) 42 mA (before the RFQ)

7. Wire scanner: comparison of the expected and measured beam profiles ExpectedMeasured x_rms (mm)3.33.1 y_rms (mm)1.51.4 7 Beam spot from the simulations

8. Conclusion We could estimate the emittance at the RFQ entrance via transmission measurements. Emittance coming out of the source is bigger than the RFQ acceptance: there is still room for improvements. Good progress towards the 50MeV commissioning. The beam current after the RFQ increased significantly (compared to last year). We have 30 mA beam (at 3MeV) for the beam commissioning at 50 MeV. Confirmed the beam we have at 3MeV (important input for the preparation of 50MeV commissioning). We need 40-45 mA in MEBT to meet the specifications for the LHC beam. 8