February 17-18, 2010 R&D ERL Dmitry Kayran R&D: G5 test and Commissioning Plan Eduard Pozdeyev, Dmitry Kayran BNL R&D ERL Review February 17-18, 2010 R&D ERL R&D: G5 test and Commissioning Plan

February 17-18, 2010 R&D ERL Dmitry Kayran Why we are doing the G5 test? G5 test is first stage of ERL commissioning –Most of all ERL components can be tested during G5Test Will demonstrate of high brightness SRF Injector operating The high energy at the end We will measure: »Projected emittance in both planes »Bunch length and longitudinal tails »Slice emittance »Energy spread To have a base line for comparison of straight line and z-bend merger system performance

February 17-18, 2010 R&D ERL Dmitry Kayran G5Test: Components SRF Gun and 5cell cavity, Cryosystem for both 1MW Klystron and 50kW RF power supplies, LLRF Vacuum chambers, pumps, control Cathode, Deposition System, Transport Car, Laser, Laser Control Magnets and Power Supplies: HTS solenoid, solenoids, steering dipoles, quadrupoles, 14° dipole (ERL 60° dipole will be used) Instrumentation: beam profile monitors, beam position monitors, beam current monitor

February 17-18, 2010 R&D ERL Dmitry Kayran ERL setup

February 17-18, 2010 R&D ERL Dmitry Kayran G5 setup: no ERL loop in place, low average power

February 17-18, 2010 R&D ERL Dmitry Kayran Main parameters Charge per Bunch: nC Gun Energy: MeV Maximum Energy: 20 MeV Max. Average current: 500 nA Max. Rep Rate: 100 Hz Average Power: < 10 W First stage: G5 test setup SRF 5cell cavity SRF Gun Triplet Beam Profile Monitor Dipole Solenoids

February 17-18, 2010 R&D ERL Dmitry Kayran Electron beam parameters and regimes for G5test Start-upBase lineHigh charge CathodeCooperMulti-Alkaline Long. Pulse shape (FWHM)12 psec Sin(x)/x50 psec flattop70 psec flat top Trans. Pulse shapeGaussian2.5 mm sharp edge3 mm sharp RF frequency MHz Operational regemPulses of trains Rep. rate in train9.383 MHz Train length100 pulses Trains rep. rate0-1 Hz Charge per bunchupto 50 pC1.4 nC5 nC Gun kinetic energy2.0 MeV 2.5 MeV Max. Energy20 MeV Max average current0.001 mA Max average power20 W

February 17-18, 2010 R&D ERL Dmitry Kayran Quad Scan / Energy Analyzer At 20MeV two operational modes: 1.Straight ahead –projected emittance –transverse halo 2.With the bend –bunch length / long. halo /energy spread –slice emittance GUN S FCT Halo monitor S 5 cell RF - BPMs FC ERL quad triplet quad interchangeable screen/slit 0.3 m 14º - OTR/YaG screens Pepper-pot S Plan to do at low energy - Cathode QE and Cathode lifetime in SRF gun - Slice emittance - Projected emittance - Halo studies

February 17-18, 2010 R&D ERL Dmitry Kayran Achievable emittance (simulations) Gun 5-cell Solenoids (the last one is off) 1.4nC, BC L: 12º RF E: 2 / 16.7 MeV  : 1.3 µm 1.4nC Realistic L: 12º RF E: 2 / 16.7 MeV  : 2.3 µm 5nC, BC L: 14º RF E: 2.5 / 17.2 MeV  : 1.7 µm T c =0.4 eV Pepper-pot

February 17-18, 2010 R&D ERL Dmitry Kayran High-energy part Two operational modes: Straight ahead –projected emittance –transverse halo With the bend –bunch length / long. halo –slice emittance ERL quad 3let ERL quad 2let interchangeable screen/slit 16º Last flange of the 5-Cell Cavity YaG/OTR viewers

February 17-18, 2010 R&D ERL Dmitry Kayran Straight ahead path ERL quad triplet Last flange of the 5-Cell Cavity 0.25 m0.728 m1.7 m Observation station: expected min. rms. beam size ~ 130 μm. (Resolution ~55 μm) All triplet quads ON : G1=70.3, G2=-117, G3=66.6 G/cm (G max =400 G/cm) Beta-functions simulated by Parmela (All energies) and MADX (Cent. Energy only) Beam kinetic energy (MeV, Parmela): E ref =16.77 E max =16.8 (+0.2%) E min =16.2 (-3.4%) BC, 1.4 nC

February 17-18, 2010 R&D ERL Dmitry Kayran Quad Scan: projected emittance Energy spread within the beam was a concern Only one quad of the 3let is used. Two other quads are off. Distribution: q=1.4 nC, BC. Vertical quad scan 2 nd quad scanned σ y, min =180 µm X max =±1 cm  y (PARM)=1.35e-6  y (“MEAS.”)=1.4e-6 Horizontal quad scan 3 rd quad scanned σ x, min =130 µm Y max =±1 cm  x (PARM)=1.35e-6  x (“MEAS.”)=1.41e-6

February 17-18, 2010 R&D ERL Dmitry Kayran The bend: energy and slice emittance ERL quad 3let ERL quad 2let interchangeable screen/slit 16º Last flange of the 5-Cell Cavity YaG/OTR viewers Nominal 3letx 1.1 nom. strengthx 0.9 nom. strength Triplet+dipole strongly focuse horizontally, regardless energy, providing good resolution

February 17-18, 2010 R&D ERL Dmitry Kayran Phase shift and slice cut Y vs X X vs Z 1 mm slit cuts a few degree slice Energy vs phase for 173º and 193º RF phase slit

February 17-18, 2010 R&D ERL Dmitry Kayran Slice parameters of misphased beam Optical functions show almost no difference for misphased beam. (Only X functions shown) Normalized slice emittance. No difference for misphased beam. (Only X emittance shown) Requirement for slice parameter measurements: Off-cresting should not strongly affect slice emittance and optical functions Slice  ’s and  ’s Slice normalized emittance

February 17-18, 2010 R&D ERL Dmitry Kayran Quad scan after bend  =3.5 m,  =-3.5, dp/p=0  =2 m,  =-2, dp/p=-0.1  =7 m,  =-7, dp/p=+0.1  =2 m,  =-2, dp/p=+0.1  =7 m,  =-7, dp/p=-0.1 Scheme is capable of accepting a large spread of initial optical functions Only vertical slice emittance is measured. Horizontal?

February 17-18, 2010 R&D ERL Dmitry Kayran G5test: conclusions G5 test will allow to check all majar components of R&D ERL gun, 5-cell cavity, diagnostics, control and other Developed G5 test + instrumentation will be good enough to measure Beam parameters : Projected Emittance Slice emittance for different time slices Bunch length and longitudinal tails

February 17-18, 2010 R&D ERL Dmitry Kayran BNL R&D ERL Status: complete (more about ERL status Schedule tomorrow) Design of major ERL components is completed. Hardware components are being manufactured and/or procured. ERL Enclosure (Vault) was constructed (2005) 5-cell Cavity is being processed and tested at JLAB, installed at 912. First cool down T=2K in March First Horizontal Cold Emission Test April 2009 The preparation chamber for SRF gun photo-cathodes under vacuum studies 1 MW Gun klystron (for SRF gun) including circulators and dummy loads installed, tested for full power 1MW 50 kW (for 5 cell 20 MeV SRF linac) installed, tested Recirculation loop magnets and injection line magnets have arrived and measured. Magnets power supplies were delivered/ installed. Loop vacuum system components have been delivered.

February 17-18, 2010 R&D ERL Dmitry Kayran BNL R&D ERL Status (count.) : RF control will be based on the new digital RHIC LLRF. The LLRF system is currently under development. (CET will use PLL based LLRF and move to digital LLRF then one is available). Machine protection system and control system (for CET) is installed/tested operational since April 2009 Laser room completion (April, 2009) Laser Gun drive laser arrived/installed/tested in May-June, 2009) G5 test additional components are designed/ordered (June 2009) Gun has been built at AES (November 2009) now is under vertical CETest in JLab to do list.. –SRF Gun Horizontal Cold Emission Test at BNL February 2011 –The magnets, vacuum system components G5 test will be installed during 2010 –ERL Extraction line component, magnets, vacuum chamber under design ( summer 2010)

February 17-18, 2010 R&D ERL Dmitry Kayran Commisionnig plan: ERL fully operational in 2011 We start commissioning of the R&D ERL in cell SRF cavity cold emission test (first cool-down March, ) First, we develop the straight pass (gun -- 5 cell cavity -- beam stop) test for the SRF Gun performance studies. (Beginning of 2011) #Metal cathode (low charge per bunch) #Multi-Alkaline Cathode (up to 5nC per bunch) # Will operate in train mode 10 MHz bunches in the train with: max duty factor 2E-5. maximum average current 1 μA, max average power to the beam dump 20 W Next, a novel concept of emittance preservation in a beam merger at the lower energy will be tested ( 2011) After recirculation loop completed, demonstrate energy recovery of high charge and high current beam. The prototype will serve as a test bed for studying issues relevant for very high current ERLs (end of 2011 ) Proof of principle coherent electron cooling ions in RHIC at ~ 40 GeV/n is feasible with existing R&D ERL parameters ( ERL available around 2012 )

February 17-18, 2010 R&D ERL Dmitry Kayran 2-3 MeV 20 MeV 2-3 MeV SC RF Gun SC 5 Cell cavity Beam dump BPM DCCT 1MW Klystron SRF Linac 50 kW Transmitter ready to operate Arc assembly QuadrupoleDipole Tested in BLD912 ready for gun First cool- down, March, 2009 T=2K Measured, ready to be installed BNL R&D ERL: in pictures

February 17-18, 2010 R&D ERL Dmitry Kayran Thank you! After the next talk there will be R&D ERL facility tour starts today at 10:50 a.m.