Instrumentation for Linear Collider: Beam Position Monitors (BPS) for CTF3-CLIC

1. Instrumentation for LC: BPS for CTF3-CLIC Multi-OTR for ATF2-ILC FONT for ATF2-ILC IFIC Accelerators Team (GAP) J. Alabau Gonzalvo C. Belver Aguilar C. Blanch Gutiérrez J.V. Civera Navarrete A. Faus Golfe J.J. García Garrigós S. Verdú Andrés

2. CLIC: The Compact LInear Collider Each sub-system pushes the state-of-the art in accelerator design The peak RF power required to reach the electric fields of 100 MV/m amounts to about 275 MW per active meter of accelerating structure. Not possible with klystrons. Hence a novel power source, an innovative two-beam acceleration system, in which another beam, the drive beam, supplies energy to the main accelerating beam. [Courtesy of CERN Courier]

3. CTF3: The CLIC Test Facility 3 • To demonstrate the Two-beam acceleration scheme. • A scaled facility for one branch of the Drive Beam Generation System Layout of the CLIC EXperimental area (CLEX) building with TBL [Courtesy of S. Doebert]

4. BPS: Beam Position Monitors for TBL The TBL is designed to study and validate the drive beam stability during deceleration in CTF3. The TBL consists of a series of FODO lattice cells and a diagnostic section at the beginning and end of the line. Each cell is comprised of a quadrupole, a BPM (labeled as BPS) and a Power Extraction and Transfer Structure (PETS) . • The BPS pick-ups main features are: • Position and also beam current monitoring • High dynamic range (30mA to 30A signals) • Broadband operation, captures the beam long pulse • Complex mechanics 3D View of a TBL cell with the PETS tanks, the BPS’s and the quadrupoles BPS unit. Type: Inductive Pick-up (IPU) 2.25 cm PCB with H and V Inductive sensors TBL beam time structure

5. BPS: Beam Position Monitors for TBL The BPS is an Inductive Pick-Up BPM BPS first prototype parts and design BPS-1 prototype • Four Outputs with two Calibration inputs: • [V+,V-, H+,H-] and [Cal+, Cal-] • Beam position determination through: • xVα ΔV /Σ [V plane]; xHα ΔH /Σ[H plane] • ΔV ≡(V+ − V-);ΔH ≡(H+ − H−); Σ≡(V+ + H+ + V− + H- ) BPS on-board PCBs: inductive sensors [Col. with G. Montoro, UPC (BPS Amplifier dev)]

6. BPS: Beam Position Monitors for TBL BPS Prototypes, Series Production and Calibration Tests • A set of two BPS prototypes labeled as BPS1 and BPS2 with its associated electronics has been designed, constructed and characterized by the IFIC team with the collaboration of the CTF3 team at CERN (May 2008). • BPS1, jointly with its support and its amplifier, was installed successfully at TBL; BPS2 remained at IFIC as spare (July 2008). • BPS1 first beam measurements were carried out (August 2008). Wire set-up for BPS prototype characterization tests at CERN Labs BPS1 and its support installed in the TBL line First measurements of the BPS1 with beam in the TBL line (OASIS Viewer) • The BPS series production (15 units) started at IFIC labs (November 2008). • A new wire test bench for BPS series characterization tests was designed and built at IFIC (March 2009).

7. BPS: Beam Position Monitors for TBL The BPS Series Characterization Tests Main features of the test stand: The Wire-Method Test Stand • The BPS under test will be moved by a motorized XY and rotatory micromovers to change the relative wire position with respect to the BPS; mounted on a pneumatic isolation work-station to avoid wire vibrations; the XY linear stages have a percision/resolution of 2/0.2 μm and 0.2/0.009 μrad for the rotatory stage. • A PC running the application SensAT-v1.0 developed in LabVIEW acquire the {ΔH, ΔV, Σ} signals and the wire position managing for that, the VNA (or the scope for pulse tests) and the micromovers controller, respectively, through GPIB bus. The automation of the test equipment allowed us to program the measurements for each BPS unit of the series, what guaranteed high repeatability and reduced test time (favouring data taken). Schematic view of the BPS Instrumentation setup, showing the sensitivity test main configuration, and the frequency and pulse tests configuration (dotted lines). SensAT-v1.0: Control & DAQ app. front panel (LabVIEW)

8. BPS: Beam Position Monitors for TBL BPS Prototypes, Series Production and Calibration Tests (cont’d) Characterization Tests Benchmarks • Tests for BPS2 and BPS3 carried out with the new wire set-up at IFIC. Less than 50um accuracy (March 2009). • Two more BPS units was delivered and installed, BPS2 and BPS3 both with new improved electronic PCBs (May 2009). Characterization parameters averaged over the 16 BPS units • 14 BPS units construction and assembly process finished (August 2009). • A LabVIEW application (SensAT v1.0) is developed for automatize the BPS series characterization tests in the new wire test bench (September 2009). • The 14 BPS units tests finishes, they are delivered to CERN and finally installed in TBL (October 2009). • All the BPS are validated successfully in TBL after first calibration tests (October 2009). • Summarizing, 16 BPS + 1 spare units (with its alignment supports) has been designed, constructed and tested for TBL. Input calibration signals test in TBL shows good BPS performance with flat-top pulse response. Frequency response (100Hz-300MHz) and position calibration fits (±5mm) of the 16 BPSs units. Observe linearity error within the precision specification (being less than 50um).

9. BPS: Beam Position Monitors for TBL 16 BPS units jointly with its suppots and amplifiers installed in CTF3 at TBL (CLEX bdg. 2010, CERN) • BEAM TESTs will be performed in TBL for the full installed BPS series (November 2010): • Measurements at high beam current (30A) and checking of the BPS’ resolution and performances. View of aTBL cell with the PETS tanks, the BPS’s and the quadrupoles Beam direction Beam direction

10. BPS: Beam Position Monitors for TBL • In colaboration with: • Prof. Benito Gimeno, Dpt. Física Aplicada-UV • Tests carried out at: • European High Power Space Laboratory, VSC-ESA The BPS High Fequency Test The HF Coaxial Testbench • The wall current HF components (above the BPS bandwidth) will flow through the inner surface of BPS vaccum pipe due to a Ti-coating, because it is the low inductance current path of the BPS. This limits the longitudinal impedance, Z||, at high frequencies. • It is important to keep the real part of Z|| limited, and as small as possible, since high Z|| produces stronger wake-fields increasing so the beam instabilities. • Therefore, the aim of this test is to measure, Z||, of the BPS beyond the beam bunching frequency, 12 GHz (microwave bands region), and check whether Z|| is limited or not. • An ultra-relativitic electron beam can be emulated by a coaxial transmission line because the EM field of the beam coupled with the vacuum pipe propagates as a TEM mode like in a 50Ωcoax waveguide. Design and Simulations 50Ω matched cone transitions from 7mm APC connectors to 24mm BPS vacuum pipe diameter Scattering Parameters Test and First Results • Measurement of S-params of the HF setup with a VNA (Vector Network Analyzer) in the range of 18MHz to 30GHz. • The coaxial setup with a drift, instead of the BPS insertion, is used for reference measurements of S-params and must have as lowest as possible reflection cofficient, S11. Z divergence in the BPS at 6.7GHz [Under study] S11; -20dB S11; -40dB Below 12 Ω until 14.5GHz ~22 GHz Freq Range:[DC-30GHz] ~18 GHz Freq Range:[18MHz-30GHz] FEST3D simulation. Only TEM modes on propagation until 22GHz (useful setup BW). Other modes are excited beyond 22GHz. Real part of Z|| determination until 30GHz from the S21 parameter measurement of the setup without and with the BPS inserted. S-params measures of the reference setup. Mechanical realization deteriorates S11 but still below 20dB until 18GHz (7mm connectors BW).

11. CLIC: Drive Beam BPM for the 1st CLIC module The drive beam quadrupole and BPM are mounted on the drive beam girders. BPMs cannot be moved independently of the PETS, the quadrupoles will either be on movers, or equipped with dipole corrector coils. The BPMs are mounted before quadrupoles. The acceptable level of wake field needs to be determined. Nominal beam parameters: Charges/bunch: 5.2 1010 Nb of Bunches: 2922 Bunch length: 1mm Train length: 243.7ns DB BPM

12. ATF and ATF2:Multi-OTR System Emittance determination by beam size measurements diagnostic section 5 wire scanners 4 OTR monitors OTR monitor (OTR) extraction BDS + Final Focus Testbench  Reach 37nm vertical emittance Emittance measurements with the wire scanners located in the diagnostic section of the EXT line are very slow (~1 min.)  Jitter of beam position leads to oversized beam size and emittance (Integrated measurements). • Multi-OTR will take faster measurements (One shot meas.) Able to measure beam size with the jitter IIFIC’s Accelerator Group jointly with SLAC: beam dynamics studies, design, construction, and characterization including associated software control and electronics.

13. ATF and ATF2: Multi-OTR System diagnostic section extraction OTR1X OTR0 OTR1 OTR2 OTR3 OTR4 The location of the OTR’s was optimized such that the phase advances were apropriate to allow emittance measurements  In a Free Dispersion Region. Simulations: Beam dynamics were calculated with MAD to study the beam sizes in order to place the OTR’s. 13

14. Beam spot measurement with old OTR ATF and ATF2:Multi-OTR System The old OTR was updated with a new target and target actuator, calibrated and tested with beam during November ´09. New design’s features: -Smaller design: greater flexibility in the OTR placement -Thinner target: reduce radiation damage -Greater depth of field. -12 bit camera: better dynamic range and resolution. -Calibration lamp The new four OTR’s were installed in May 2010. First beam tests were made with some target material issues to solve. New OTR installed on the EXT line New design assembly

15. ATF and ATF2:Multi-OTR System • Control Software features: • Programmed in Matlab for integration in Flight Simulator and EPICS. • Easy-to-use, performs fast emittance measurements just with one click. • At the moment, optimizing the emittance reconstruction algorithm. • To be implemented and tested in November 2010. New design of the OTR for ATF-ATF2

16. ATF and ATF2:BPM’s supports with micromovers for FONT4 FONT – Feedback On Nanosecond Timescales IP intra-train feedback system • Last line of defence against relative beam misalignment • Measure vertical position of outgoing beam and hence beam-beam kick angle • Use fast amplifier and kicker to correct vertical position of beam incoming to IR

17. Movers installed at ATF2 ATF and ATF2:BPM’s supports with micromovers for FONT4 • Development of 3 vertical and horizontal micromovers •  Realignment of BPM to increase resolution. • IFIC’s Accelerator Group: design, construction, and characterization including associated electronics and control software development. Installation was finished in March 2010 and they are already working properly. Realistic simulations of the beam dynamics including the FONT feedback system are being made. Strip-line BPM Range: ±1 mm Step size: 10 μm Stability better than 1 μm Time response ~ sec LabView Control Program

18. Thank you!! Instrumentation for LC: BPS for CTF3-CLIC Multi-OTR for ATF2-ILC FONT for ATF2-ILC IFIC Accelerator Team: J. Alabau Gonzalvo C. Belver Aguilar C. Blanch Gutiérrez J.V. Civera Navarrete A. Faus Golfe J.J. García Garrigós S. Verdú Andrés