1. CHARGES TO THE ESAC The External Scientific Advisory Committee for the HIPPI JRA inside CARE has been nominated to analyse the work done and planned in the frame of HIPPI to give advice to the HIPPI management, by making assessments and by providing recommendations. More specifically, the following questions have to be addressed: # 1 (general) Please review and comment the overall scientific quality of the research carried out. What were the most important accomplishments of the last year? How does the work compare with the international level? # 2 (labs & groups) Does the work presented by the different labs match with the HIPPI work plan for the first 18 months? Is it consistent and sufficiently transparent scientifically? Comment on the proper use of resources in the first year. Is it clear how the groups proceed in the second year? # 3 (WP's) Comment on the effectiveness of interaction within WP's. Is there enough visibility of WP collaboration? Comment on what needs to be strengthened.

2. WORK PACKAGE 4 Compare two approaches. Both use electrostatic deflection Differences: amplifier design, duty cycle?, beam line design Beam chopping tasks Broad band kickers [CERN] Objectives: switching time smaller than the distance between bunches at 352 MHz (about 2 ns); chopper-line design minimizing emittance growth, cleanliness of gap Separate fast/slow kickers [RAL]

3. WP4 (Beam chopping) (1/2) Accomplishment –CERN: Lay-out design frozen Meander plates development New bipolar amplifier design based on solid state components an hybrid couplers Built and tested Meets rise time specs (<2ns rise time) 3% noise ok for Beam dynamics –RAL Procurement and test of single and dual polarity generator 2.8% corrected droop Slow Pulse Generator prototyped and tested Evaluated three chopping schemes Quality –High quality and represents the standard in this area –Work addresses objectives

4. Planning WP4 (2/2) Collaboration –Improved and their designs benefited from collaboration –Collaboration with WP5 Recommendations 04 –Integrate beam line design with linac design (ok for Linac4) –Investigated testing both prototype at CERN (pending) –Stronger collaboration (demonstrated) Recommendations 05 –Simulate RAL design on linac4 –Produce a test plan

5. WORK PACKAGE 2 Normal Conducting Accelerating Structures DTL Alvarez [CEA, LPSC,CERN] CH [IAP-FU] CCDTL [CEA, LPSC,CERN] Development of cold models and some prototypes of NC RF structures for acceleration up to an energy of ~ 100 MeV, Prepare comparative assessment with respect to SC solutions Objective: comparative assessment in terms of shunt impedance (goal : ZT 2 > 40 M  /m) and cost, in the energy range 3-100 MeV SCL [LPSC,CERN]

6. WP2 (NC linac) (1/2) Accomplishment –CEA Cold model of the 352 MHz iris coupler built and tested –Frankfurt: design and simulations CH structure for FAIR, (low duty) –CERN frozen design of linac4 DTL,CCDTL; CCL Contract for construction of DTL prototype CCDTL prototype fabricated SCL design program –RAL preliminary DTL design study –LPSC SCL thermal design Quality –The quality of the physics work is good –The mechanical design of CERN DTL prototype has improved

7. WP2 (2/2) Collaboration Recommendations 04 –Compare NC and SC solutions –investigate DTL technologies in other labs (SNS, KEK/JAERI, Korea KOMAC) (quads…?) Recommendations 05

8. WORK PACKAGE 3 Characterization of SC RF structures for use in a pulsed linac. Investigation of different type of structures; prepare for comparative assessment Realization of a high power 704 MHz RF test place with cryogenic infrastructure Superconducting Accelerating Structures Spoke (low beta) [FZJ, Orsay] Multi-cell elliptical (medium/high beta) [CEA, INFN] CH (low/medium beta) [IAP-FU] Objectives: gradient > 7 MV/m with Q > 10 10 in the energy range 100-200 MeV, at a construction cost comparable to normal-conducting structures; development of efficient superconducting structures down to beam energies around 5 MeV; availability of a 704 MHz high power RF test place for SC cavities.

9. WP3 (SC linac) (1/2) Accomplishment –Frankfurt: 19 gap prototype of superconducting CH built and tested. Tuner design in progress. –INFN Analysis of KL measurements, dominated by the stiffness of the frame system, and design of the coaxial tuner –CEA Analyzed and designed a symmetric elliptical cavity 704 MHz elliptical cavities (b=0.47). Cavity B construction proposal. –FZJ Triple spoke cavity 760 MHz (b=0.2), prototype tested Triple spoke cavity 352 MHz (b=0.48) engineering design Analysis of slot finger structure –IPN Construction and test of a b=0.15 Spoke Cavity Quality –The general quality is good

10. Planning WP3 (2/2) Collaboration –Good collaboration Recommendations 04 –Agree on definitions of E 0 –Investigate possibility of optimizing design the elliptical cavity for LFD, or concentrate on piezo. –Collaboration with SNS on elliptical cavity operational issues –Investigate multicavity power/control scenarios –Compare NC and SC solutions Recommendations 05