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Accelerator R&D for Future Linear Colliders at

IFIC

Scientific Staff:A. Faus-Golfe, C. Alabau, J.J. García, S. Verdu, J. Alabau

Technical Staff: J.V. Civera, C. Blanch

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Capabilities

- CALCULATION

BEAM DYNAMICS EXPERTISE:

Electromagnetic analysis

• Electric circuits & electronics

Mechanical analysis

Optics design

Non-linear dynamics studies

New instrumentation techniques

Commissioning

3-D modelling ot BPM

Optics study for LHC non-linear collimation sysytem

- PROTOTYPING

Design: tooling, drawings

Fabrication follow-up

Assembly

Testing

BEAM INSTRUMENTATION :

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Main ongoing projects

ATF-ATF2:

Beam dynamic studies and commissioning of the EXT line (LAL, KEK, SLAC)

Instrumentation: New Multi-OTR system (SLAC, KEK)

BPM supports with micromovers for FONT4 (KEK, JAI)

CLIC-CTF3: BPM’s for TBL (UPC, CERN)

Pieces of BPM-TBL for CTF3

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ATF was built in KEK (Japan) to create small emittance beams.

The Damping Ring of ATF has a world record of the normalized emittance of 3x10-8 m rad at 1.3 GeV.

ATF2 is being built to study the feasibility of focusing the beam into a nanometer spot (~37 nm) in a future linear collider.

Extraction line drives the beam

from ATF to ATF2

Main Ongoing Projects:ATF and ATF2: Emittance growth studies

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(OT

R)

extractiondiagnostic section

wire scannersOTR monitor

ATF and ATF2: the Extraction Line

Hypothesis:

Since several years, the vertical emittane measured in the diagnostic section of the EXT line is significantly larger than the emittance measured in the DR.

Non-linear magnetic fields while passing off-axis through the shared magnets

The beam passes horizontally off-axis through the shared magnets with the DR

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ATF and ATF2: Non-linear magnetic fields

Computation of the non-linear magnetic fields of the magnets involved in the extraction with the code PRIAM

Extracted beam

BS1X septum magnet

QM7Rquadrupole

Multipole coefficients:

Polynomial fit of the magnetic field:

Dipole component appears

Quadrupole component reduced ~ 24% with respect to the DR

Non negligible sextupole component

At the extraction (x=2.25 cm):

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ATF and ATF2: : Tracking simulations including non-linear fields in different magnets of the extraction

The non-linearity would have negligible effect if the beam were always centerd vertically, but increases when passing vertically off-axis through QM7R.

The magnitude of the growth also depends on the horizontal displacement, increasing or decreasing in the outer and inner parts of the magnet.

Experimental Proposal open the bumpin DR and EXT

offset in QM7

close the bump in the DR OTR monitor

Closed orbit bumps in the DR are used to deviate the extraction trajectory and study its correlation with the emittance growth

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ATF and ATF2: Experimental Work (Dec’07-May’08)

Measurements during different shifts:

Beam size at the OTR/XSR Beam size at the OTR/XSR

Measurements + simulatios for different horizontal extraction positions:(28th May’08) (19th Dec’07)

- The results show an emittance growth with a strong dependence with the extraction position.

- But still there must be another source for the emittance growth since in three of the data sets the extracted beam was significantly larger than expected. It could be doe to an anomalous dispersion, a large horizontal displacement or to another mechanism.

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ATF and ATF2: Conclusions

Simulations including the non-linear fields in the extraction region predict a significant vertical emittance growth while passing throug QM7R vertically off-axis.

The magnitude of the growth depends on the horizontal displacement, since the non-linearity decreases going towards the center of the magnet.

Measurements using closed orbit bumps in the DR to probe the relation between the extraction trajectory and the emittance growth were done:

- The results show an emittance growth with a strong dependence with the extraction position. - But still there must be another source for the emittance growth since the extracted beam was significantly larger than expected in three of the data sets.

Recently, the QM7R magnet was replaced by a similar one with larger aperture, for which magnetic measurements and simulations indicate that non-linear fields are negligible at the extraction position.

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Main Ongoing Projects:

Emittance measurements with the wire scanners located in the diagnostic section of the EXT line are very slow.

Proposal:

(OT

R)

extractiondiagnostic section

wire scannersOTR monitor

multi OTR (4 units) (in collaboration with KEK, SLAC):

beam dynamics studies, design, construction, and characterization including associated electronics

ATF and ATF2: New Multi-OTR System

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ATF and ATF2: New Multi-OTR System

OT

R1

X

OT

R0

OT

R1

OT

R2

OT

R3

OT

R4extraction diagnostic section

The location of the OTR’s has to be optimized such that the phase advances be apropiate to allow emittance measurements

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ATF and ATF2: New Multi-OTR System

Current OTR installed in the ATF EXT line

target

CCD camera

New design of the OTR for ATF-ATF2

- Target actuator relocated to the top (no interference with the girder) and smaller design greater flexibility in the OTR placement

- Thinner target reduce radiation damage

- CCD camera parallel to the target (before it was not parallel, which meant that the beam spot was in focus on only a small portion of the target) greater depth of field.

- 12 bit camera for more dynamic range with smaller pixel size for more resolution.

New OTRs will have same controls and motion capabilities as current OTR with the following improvements:

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ATF and ATF2: BPM’s supports with micromovers for FONT4

• 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

FONT – Feedback On Nanosecond Timescales

IP intra-train feedback system

Main Ongoing Projects:

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ATF and ATF2: BPM’s supports with micromovers for FONT4

BPM’s supports with micromovers for FONT4 (in collaboration with KEK, JAI) design, construction, and characterization including associated electronics

Proposal:

Range: ±1 mmStep size: 10 μmStability better than 1 μmTime response ~ sec

Planning:1st prototype for Dec’09 (ATF2 shutdown)

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Realignment of BPM to increase the resolution

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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) .

3D View of aTBL cell with the PETS tanks, the BPS’s and the quadrupoles

2.25 cmBPS PrototypeInductive Pick-up (IPU)

TBL beam time structureInductive sensors PCB

16 Beam Position Monitors for the TBL (in collaboration with UPC, CERN): designed, constructed, characterized and tested including supports and associated electronics

CLIC-CTF3: BPM’s for the Test Beam Line

Main Ongoing Projects:

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CTF3: BPM’s for the Test Beam Line

BPS PrototypesA set of two prototypes of the BPS's 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.

The characterization has been made with the wire method in the BI-PI labs at CERN. This test is based on a test bench setup that allows moving the BPS with respect to a current wire that simulates the beam passing trough the BPS under test.

From the point of view of the electronics two different versions of the PCB's, differing in the secondary output resistors used for the adjustment of the low-frequency cut-off, has been also tested.

BPS1 Sensitivity and Linearity Parameters

V Sensitivity, SV 41.09 m-1

H Sensitivity, SH 41.43 m-1

V Electric Offset, EOSV 0.03 mm

H Electric Offset, EOSH 0.15 mm

V overall precision (accuracy), σV (+/- 5 mm) 78 μm

H overall precision (accuracy), σH (+/- 5 mm) 109 μm

BPS1 Characteristic Output LevelsSum signal level, Σ 16.5 V

Diff signals levels, ||ΔV||max, ||ΔH||max 8.25 V

Centered beam level, Vsec (xV = 0, xH = 0) 4.125 V

BPS1 Frequency Response (Bandwidth) Parameters

Σ low cut-off frequency, flΣ 1.76 KHz

Δ low cut-off frequency, flΔ 282 KHz

Σ[Cal] low cut-off frequency, flΣ [Cal] 1.76 KHz

Δ[Cal] low cut-off frequency, flΔ [Cal] 180 KHz

High cut-off frequency, fh > 100 MHz

High cut-off frequency [Cal] fh[Cal] > 100 MHz

BPS1 Pulse-Time Response Parameters

Σ droop time const, τdroopΣ 90 μs

Δ droop time const, τdroopΔ 564 ns

Σ[Cal] droop time const, τdroopΣ [Cal] 90 μs

Δ[Cal] droop time const, τdroopΔ [Cal] 884 μs

Rise time const, τrise < 1.6 ns

Rise time const [Cal], τrise [Cal] < 1.6 ns

The BPS1 and its support is already installed in the TBL line. After the installation in March 2009 some preliminary test with beam has been performed.

BPS1 and its support installed in the TBL line

BPS1 Prototype Performance

Measurements of the BPS1 with beam in the TBL line

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CTF3: BPM’s for the Test Beam Line

BPS series production and characterization

The main features of this new test bench setup is that the BPS under test is moved by a motorized XY and rotatory micromovers to change the relative wire position with respect to the wire, and, moreover, the wire is fed with a higher current (>250 mA) to avoid the low current effects in the test measurements.

Sensitivity and Linearity Parameters BPS2 BPS3

V Sensitivity, SV 43.16 m-1 43.70 m-1

H Sensitivity, SH 44.60 m-1 42.10 m-1

V Electric Offset, EOSV -0.67 mm -0.84 mm

H Electric Offset, EOSH 0.50 mm 0.52 mm

V overall precision (accuracy), σV (+/- 5 mm) 89 μm 94 μm

H overall precision (accuracy), σH (+/- 5 mm) 90 μm 98 μm

Characteristic Output LevelsSum signal level, Σ 16.5 V 16.5 V

Diff signals levels, ||ΔV||max, ||ΔH||max 8.25 V 8.25 V

Centered beam level, Vsec (xV = 0, xH = 0) 4.125 V 4.125 V

Frequency Response (Bandwidth) Parameters

Σ low cut-off frequency, flΣ 2.90 KHz 1.70 KHz

Δ low cut-off frequency, flΔ 271 KHz 275 KHz

Σ[Cal] low cut-off frequency, flΣ [Cal] 2.80 KHz 1.70 KHz

Δ[Cal] low cut-off frequency, flΔ [Cal] 163 KHz 171 KHz

High cut-off frequency, fh > 100 MHz > 100 MHz

High cut-off frequency [Cal] fh[Cal] > 100 MHz > 100 MHz

Pulse-Time Response Parameters

Σ droop time const, τdroopΣ 55 μs 93 μs

Δ droop time const, τdroopΔ 587 ns 579 ns

Σ[Cal] droop time const, τdroopΣ [Cal] 57 μs 93 μs

Δ[Cal] droop time const, τdroopΔ [Cal] 976 μs 931 μs

Rise time const, τrise < 1.6 ns < 1.6 ns

Rise time const [Cal], τrise [Cal] < 1.6 ns < 1.6 ns

BPS2 and BP3 Series Performance

The series production of the 15 unit (BPS1 + 15) have been started at the IFIC labs in November 2008. We have characterized two units: a refurbished version of the BPS2 (PCB final version) and a new unit labeled as BPS3.

Low-frequency wire set up at the IFIC labs

3D view of the Low-frequency wire

set up

DAQ equipment for all the setup signals and micromovers controller

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CTF3: Conclusions

The series production of 15 units has already started. The production of the different parts is finished.

One unit of the series: BPS3 was assembled. After the characterization test made at IFIC labs in a new wire low-frequency setup, it was shipped to CERN jointly with BPS2 and its corresponding supports.

These two units are being installed in the TBL line. The rest of the series will be installed in July 2009.

Furthermore a high frequency setup for measuring the longitudinal impedance is being constructed at IFIC. The measurements will be made during May with some of the units of the series.

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Main Future projects

ILC: BDS instrumentation studies

LHC: non-linear collimation options for sLHC (SPS experiments) (EUCARD)

IFIMED: Imaging and Accelerators applied to Medicicine

• Monitoring of secondary beams (beam position and size) (CERN; LLR, CNAO)

• Cyclinacs applications (TERA, CTF3) CABOTO: Carbon Boster for Therapy in Oncology

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