Status of REX and Commissioning with Beam Dr. Jose Alberto Rodriguez, BE-OP-PSB (167538)

Content:  Status of REX RF Systems  Commissioning with beam Completed so far Next steps  Summary Jose Alberto Rodriguez, BE-OP-PSB (x167538) 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21

RF Systems: Jose Alberto Rodriguez, BE-OP-PSB (x167538) Beam from EBIS 5 keV/u Beam to HIE-ISOLDE 2.85 MeV/u Magnets: Triplets6 Doublets1 Steerers1H, 1V Triplet IHSRFQ Buncher 7gap 17gap 27gap 39gap Triplet Doublet HV Steerer Power converters: 200 A, 50 V20 (1 spare) bipolar 3.5 A2 Diagnostics: REXHIE-ISOLDE FC MCP Collimator apertures Beam attenuators FC Si detector Scanning Slits Collimator apertures Diagnostics Status of REX Sectors10 Turbopumps~20 Cryopumps3 Gauges~25 Vacuum (incl. low energy): 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 RF Structure Final Energy [MeV/u] 4-rod RFQ0.3 Buncher0.3 IHS1.2 7gap gap gap gap2.85

RF Systems: Jose Alberto Rodriguez, BE-OP-PSB (x167538) Beam from EBIS 5 keV/u Beam to HIE-ISOLDE 2.85 MeV/u Magnets: Triplets6 Doublets1 Steerers1H, 1V Triplet IHSRFQ Buncher 7gap 17gap 27gap 39gap Triplet Doublet HV Steerer Power converters: 200 A, 50 V20 (1 spare) bipolar 3.5 A2 Diagnostics: REXHIE-ISOLDE FC MCP Collimator apertures Beam attenuators FC Si detector Scanning Slits Collimator apertures Diagnostics Status of REX Hardware refurbishment and commissioning for these systems completed and ready for beam commissioning since wk. 25 (HIE-ISOLDE diagnostics box since wk. 27). Sectors10 Turbopumps~20 Cryopumps3 Gauges~25 Vacuum (incl. low energy): 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 RF Structure Final Energy [MeV/u] 4-rod RFQ0.3 Buncher0.3 IHS1.2 7gap gap gap gap2.85

RF Systems: Jose Alberto Rodriguez, BE-OP-PSB (x167538) Beam from EBIS 5 keV/u RF Structure Final Energy [MeV/u] 4-rod RFQ0.3 Buncher0.3 IHS1.2 7gap gap gap gap2.85 Beam to HIE-ISOLDE 2.85 MeV/u Triplet IHSRFQ Buncher 7gap 17gap 27gap 39gap Triplet Doublet HV SteererDiagnostics Status of REX 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 4-rod RFQ: Functional since wk. 25 (10 Hz, 1ms, power levels up to A/Q = 4.0) Ready for commissioning with beam and physics program  New steeper motor for one of the tuners will be installed this week  Broken cooling fan will be repaired during the winter shutdown  Duty cycle and peak power requirements will be significantly higher next year (this applies to all the RF systems) Buncher: Functional since wk. 25 Ready for commissioning with beam and physics program  Phase shifter in the LLRF replaced on wk. 32 IHS structure: Powered on wk. 29, ramped up in wk. 30, functional since wk. 35 Ready for commissioning with beam and physics program  Problem with LLRF’s control PLC solved on wk. 31  Amplifier disassembled, RF tube replaced on wk. 34

RF Systems: Jose Alberto Rodriguez, BE-OP-PSB (x167538) Beam from EBIS 5 keV/u RF Structure Final Energy [MeV/u] 4-rod RFQ0.3 Buncher0.3 IHS1.2 7gap gap gap gap2.85 Beam to HIE-ISOLDE 2.85 MeV/u Triplet IHSRFQ Buncher 7gap 17gap 27gap 39gap Triplet Doublet HV SteererDiagnostics Status of REX 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 7 gap structures: Functional since wk. 32 Ready for commissioning with beam and physics program  Problem with tuner of 7gap3 solved on wk. 32  Problem with reachable range of phases of 7gap1 solved on wk. 36  Possible problem stability of 7gap1 observed (gone, but may reappear) 9 gap structure: Temporary amplifier functional since wk. 25 Ready for commissioning with beam  Final amplifier delayed. Will not available this year (implications in the maximum A/Q (<3.6) and the time structure) Peak power and duty cycle increased on wk. 36 (52 kW, 0.2%: 10 Hz, 200 us)  New RF line will be install on wk. 39 to minimize RF losses  Problem with remote phase acquisition solved on wk. 36

Commissioning with beam Stage 1: REX diagnostics box: Commissioning with beam started on wk. 25 (June 16 th ) Beam with an A/Q=4.0 was accelerated to 0.3 MeV/u (RFQ output energy) We reached the first diagnostic box and re-commissioned the FC, MCP and collimator wheel on wk. 25 Beam transmission through RFQ for different power levels on wk. 26 Beam in FC after RFQ for different collimator aperture sizes (15, 5, 3 and 1 mm) MCP image of the beam after the RFQ Diagnostic box: FC, MCP, Collimator Wheel, Beam attenuators Jose Alberto Rodriguez, BE-OP-PSB (x167538) wk. 25 // 0.3 MeV/u IHSRFQ Buncher 7gap 17gap 27gap 39gap Diagnostics Beam transmission thru the RFQ vs RF power for A/Q=4.0 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 Already reported in previous meeting

Stage 2: First HIE-ISOLDE diagnostics box: First diagnostics box of HIE-ISOLDE installed at the end of wk. 27 First beam in FC and to the Si detector with 0.3 MeV/u energy on wk. 28 Systematic characterization by E. D. Cantero and S. Sadovich on wk. 33 and after More details in the next presentation by S. Sadovich Commissioning with beam Jose Alberto Rodriguez, BE-OP-PSB (x167538) wk. 28 // 0.3 MeV/u IHSRFQ Buncher 7gap 17gap 27gap 39gap Diagnostics Screen shot of BI expert application Beam in Faraday Cup 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 Beam signal in Si detector after pre- amplifier in “oscilloscope” mode Diagnostic box: FC, Si detector, Scanning slit, Collimator slit Quad scan using scanning slits (I = 15 pA)

Commissioning with beam Jose Alberto Rodriguez, BE-OP-PSB (x167538) IHSRFQ Buncher 7gap 17gap 27gap 39gap Diagnostics Stage 3: Commissioning and phasing of RF Structures in REX: Cavities and their amplifiers were commissioned after they were turned on by the RF team Many of the problems listed in previous slides were discovered at this time Finally, operational settings (phases and amplitudes) for all RF cavities were determined 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 Energy spectrum around zero- crossing phase of the buncher Phasing of the first 7gap structure Energy of the beam for different phases and amplitudes out of the 9gap wk – 2.85 MeV/u

Commissioning with beam Jose Alberto Rodriguez, BE-OP-PSB (x167538) CM1 XLN Stage 4: Commissioning the High Energy Beam Transfer (HEBT) line: First attempt to drift beam passed the cryomodule on wk. 33 Second attempt on wk. 38 (rupture disk incident and work related to the SRF tuners) Beam all the way to the last diagnostics box of XT01 at the end of wk th HIE-ISOLDE Physics Coordination Group Meeting /09/21 CM2 (2016) wk MeV/u XLN3.0300XLN4.0300XT XT XT XT XT XT FC name Measurement (1) BI expert app. I [epA] (2) calibration for XT Transmission XRFQ.FC pA10.6 pA (used external Keithley)1.00 XIHS.FC109.3 pAReading affected by buncher XLN (1) 9.3 pA (2) 0.88 XLN (1) e - suppressor problem XLN (1) 9.5 pA (2) 0.90 XT (1) 9.3 pA (2) 0.88 XT (1) 8.9 pA (2) 0.84 XT (1) 8.9 pA (2) 0.84 XT (1) e - suppressor problem XT (1) 8.1 pA (2) 0.76 XT (1) 8.1 pA (used external Keithley)0.76 End Tunnel SC Solenoid Quad H/V Steerers Overall transmission ~75% Transmission through REX ~88% No mayor problems found (two electron suppressors don’t work) Optics model seem to work pretty well, but systematic measurements of beam properties still need to be done

Commissioning with beam Jose Alberto Rodriguez, BE-OP-PSB (x167538) CM1 Next steps (high priority):  Deliver beam from the pilot source before the trap to the end of XT01  Finalize the commissioning of the new TRAP/EBIS/RF timing system and the high level control application  Phase SC cavities and measure the energy gain of the beam (benchmark their performance)  Test machine scalability in A/Q and in energy 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21 CM2 (2016) wk MeV/u Next steps (lower priority):  Systematic measurements of beam properties (e.g. emittance, Courant-Snyder parameters…)  Benchmarking optics model and implement modifications if necessary  Finalize and commission the field regulation of the power converters for the dipole magnets Next steps (medium priority):  Improve beam transmission  Individual calibration of each Faraday cup  Cross calibration of the two Si detectors and the dipole magnets and determine error bars in beam energy measurements  Check calibrations / phases after installation of new RF line for 9gap and steeper motor for tuner of RFQ  Systematic commissioning of all the devices in the beam diagnostics boxes  Systematic checks with beam of polarities of all optics magnetic elements  Finalize and commission the beam diagnostics high level control application

Summary Jose Alberto Rodriguez, BE-OP-PSB (x167538) Status of REX:  Hardware refurbishment and commissioning of power converters, magnets, diagnostics and vacuum systems completed before wk. 25  All RF systems operational at the same time since wk. 35 (some of them since wk. 25)  Due to delay in delivery of the final 9gap amplifier, we will need to use the temporary amplifier (constrains in maximum A/Q and time structure deliver to users) Commissioning with Beam:  Commissioning started in wk. 25 and progressed as hardware was ready  12 C 4+ beam produced in the charge breeder has been accelerated to 2.85 MeV/u (REX nominal final energy) and transported to the end of the XT01 experimental line  A lot of work still needs to be completed before the start of the physics program 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21

Additional Slides Jose Alberto Rodriguez, BE-OP-PSB (x167538) 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21

Constrains imposed by the temporary amplifier Jose Alberto Rodriguez, BE-OP-PSB (x167538) Limits on peak power translate into Limits on the repetition rate translate into Limits on the maximum A/Q of the beam Possible beam contamination Limits on the maximum A of the beam Stripper foils for light ions Longer breeding time Lower breeding efficiency Lower beam current Non-usable or lower quality experimental data for heavy ions Force to operate in non-optimal of the CSD Constrains on the time structure delivered to users Limits on duty cycle translate into Unable to stretch beam pulse Lower beam current Increase operational complexity (set-up time, risk, reduces beam quality…) Limits on half- life of the beam Fortunately, only a few of these affect the experiments planned for 2015 Having the amplifier for the 2016 experimental campaign is an absolute must! Increased pile-up Lower effective beam current Fewer and longer experiments (ie. reduced physics output) 8 th HIE-ISOLDE Physics Coordination Group Meeting /09/21