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Challenges and Trends in Beam DiagnosticsProf. Carsten P. Welsch

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014First: What is oPAC ?

Optimization of Particle Accelerators

22 ESRs>30 Partner Institutions6 M

www.opac-project.eu

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Overview of ConsortiumBeneficiary partners

Associated partners

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Adjunct PartnersPart of the long term strategy oPAC is growing

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Why needed ?Well suited as cross-sector collaboration is key to our research.Essentially all large-scale experiments require international cooperation

Research area needs significantly more trained accelerator experts; Few universities in EU provide structured courses oPAC drives innovation in researcher training

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014WP2 Beam physicsDevelopment of designs for possible LHC upgrade optionsAdvanced beam physics problems at light sourcesOptics and lattice design studies for the interaction region design of the LHC experimental insertionsLHeC as a future upgrade option of the LHCSimulation studies into halo generation in high brightness hadron beamsStudies into beam loss patterns at ESSDesign and development of resonant structures as Schottky noise detectors for various frequenciesOptimization of the layout of the LHC collimation systemImprovement of the understanding of non-linear beam dynamics effects in light sources

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014WP3 Beam DiagnosticsBeam halo monitor developmentOptimization of beam instrumentation for light sourcesCryogenic SQUID-based beam current monitorBeam Loss Monitors for use in Cryogenic Environments Methods for measuring the beam profile in high intensity beamsLaser-wire beam profile monitor for measuring the transverse beam profile of an H- beamOptimization of 10Be detectionDesign a detection system for verifying a 3D method of image reconstruction for Intensity Modulated Radiotherapy Treatment (IMRT)

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014WP4 Simulation ToolsIncluded in most R&D project, plus:

Development of a simulation suite based on the multilevel fast multipole method

Development of a GPU-based PIC solver

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014WP5 Control SystemsLinks all R&D projects, plus:

Adaptation of existing open-source control systems from compact accelerators to large scale facilities

Improvement of the process to identify the needs for accelerator instrumentation

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

WP6 - TrainingObjective: Train the next generation of accelerator experts in best possible wayProvide them with ideal skills basis for their future careersPromote collaboration and cross sector exchangeSecondments to under how R&D works at different placesMotivation: Ideal Training.Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Training each Network NodeProvide trainees with broad skills base100% focus on research projectIn accordance with national (PhD) regulationsEnable secondments between nodesPromote knowledge exchange and collaboration across the networkInitial plan fixed in CDPs, additional opportunities already taken (e.g. JUAS, IPAC, etc.)

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Network-wide TrainingSchools in Accelerator Physics (CAS, JUAS) and Complementary SkillsTopical Workshops on focused research areasTraining Days on expert topicsConference and Symposium to summarize and disseminate research results internationallyProvision of seminars, contributions to conferences, etc.Secondments between partners

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Diagnostics ChallengesAdvanced beam diagnostics methods (examples)Non-invasive beam profile monitoringAbsolute measurement of nA beamsBeam loss monitors and detector technology

Limitations and open questionsProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

From profile to halo

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014IPMSouce: J. Egberts, CEA

Based on ionization of rest gasChallengesRequired residual gas pressure1D beam profile only

Peters and Charlottes talkProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014BIF MonitorMeasures light from rest gas, excited by beamChallenges:Very low cross sectionsIsotropic light emissionRest gas pressure requirements

F. Becker, GSIPeters and Charlottes talkProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Atom Gas Jet

Proof-of-principle setup at the CI;Gas jet and IPM;Designed for use with low energy antiproton beams:Profile MonitorCollision experiments.

V. Tzoganis, A. JeffM. Putignano, et al., Nucl. Instr. Meth. A (2012).V. Tzoganis, APL (2014), accepted.

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Electron Beam ScannerDerive beam profile from deflection of low energy electron beam scanned across the high energy proton beam

Courtesy of W. Blokland and R. JonesProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Look at the deflected projection of a tilted sheet of electrons

dydxQuadrupolesDeflectorElectrons

Multiple scanstake the derivative to get the profileCourtesy of W. Blokland and R. Jones.Electron Beam ScannerProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Courtesy of W. Blokland and R. JonesChallengesProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Definition: What is 'Halo' ?

General definition difficult to make:Accelerator physicistsInstrumentation specialistsLow density / difficult to measureProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014ProblemVery high intensity in core:Saturates pixelsSignal overflow to neighbouring pixelsTail regions are being modified, falsified measurement.

Solution: Concentrate measurement on tail region ONLY as this is the interesting part !

How ??

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014SOHO

*Solar and Heliospheric ObservatoryProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Halo Monitoring: Core Masking(1) Aquire profile

(2) Define core

(3) Generate mask(4) Re-Measure

C.P. Welsch et al.,Proc. SPIE (2007)

J. Egberts, et al., JINST 5 P04010 (2010)Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014241024 x 768 pixels (XGA)USB Interfacehigh-speed port 64-bit @ 120 MHz for data transferup to 9.600 full array mirror patterns / sec (7.6 Gbs) 16 mm in size+/- 12tilt angleSwitch of 15 ms physically, 2 ms optically

Basis: Micro Mirror Array (TI)

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Measurements at UMER10 keV e- beam, Phosphor screeniCCD cameraVerification of earlier lab measurementsReconstruction of beam profile with DR of 105Effects from diffraction on DMA are minimal

H. Zhang, et al., Phys. Rev. STAB 15, 072803 (2012)!!Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014AdvantagesCan be used with any raditiation (OTR, ODR, SR, Smith-Purcell, Cherenkov, etc.);Suitable for any charged particle beam;Advanced measurements possible: XDR, emittance, phase space mapping, injection optimization, etc.More to come...See Blaine s talk

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Additional challengesApproaching the resolution limit, e.g. sub 100 nm beam size measurements using OTR (Pavel and Konstantin);

FELs and Light Sources (Volker and Laura);

Laser wire scanners (Thomas).

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Tiny currents absolutely !

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Absolute Current MeasurementHighly desirable !Callibration of other monitors,Direct link to experimental output.

Challenges:Signal levels VERY low,Signal/noise critical,Isolation against vibrations, rf noise...many more...

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Cryogenic Current ComparatorThe CCC consists of:

SC pickup coil,

High efficient SC shield,

High performance SQUID measurement system.Harvey, Rev. Sci. Instrum. 43 (1972)DITANET: Febin

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

SQUIDSuperconducting QUantum Interference DeviceMost sensitive magnetic flux detector,

The working principle makes use of:Superconductivity,Flux quantization in SC rings, Josephson effect.

A SQUID consists of a SC ring with one or two weak links (Josephson tunnel junctions). Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Measurement PrincipleCouple to azimuthal magnetic field,Screening current induced in SC coil with ferromagnetic core,DC SQUID for sensitive detection of coil magnetic field,Strong shielding against magnetic noise is key !(14 ring cavities give 200 db shielding factor)

M. SchwickertProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Prototype @ GSIGSI prototype (A. Peters, 1997)

Resolution:250 pA/Hz 8 nA (1 kHz readout) 2109 U28+/s

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014More recently...

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

Challenge: accurately measure low-intensity beams

Proposal: measure induced magnetic field with a SQUID

Crucial: tiny level of signal magnetic field requires advanced shielding strategy

ELENA CCCCourtesy of MiguelProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014

and losses ?

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Beam Loss 5 MW beamsPower density, in Gy/sec, for 1 W/m distributed beam loss on a beam pipe, at 200 MeV and 2 GeV.Additional Monte Carlo Studies required, different loss scenarios under consideration lot of expertise at CI

Source: M. Jarosz, ESS Proc. IBIC (2013)

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Diamond DetectorsFast & sensitiveUsed in LHC to distinguish bunch by bunch lossesInvestigations now ongoing to see if they can work in cryogenic conditions See Pavel and Erichs talks39

Courtesy of E. GriesmayerProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Cryogenic MonitorsSiliconSuccessfully used at 1 K at CERN in 1976DiamondSuccessfully in use as LHC BLM at room temperatureBetter resistance to radiation than Si at room temperatureLess leakage current than Si at room temperatureDoes it work in liquid helium?Liquid helium ionisation chamberAdvantage : no radiation hardness issueDisadvantage : slow (charge mobility of 0.02 cm2/V/s)Courtesy of R. Jones see Marcins talkProf. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Where to go...from here ?

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Upcoming EventsSchool on Accelerator Optimization (July 2014)School on Laser Applications (September 2014)Topical Workshop Beam Diagnostics (March 2015)Conference on Laser Applications (March 2015)Outreach Symposium, Liverpool (June 2015)Conference on Accelerator Optimization (October 2015)

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014Stay tuned !!URL:(http://www.)opac-project.eu

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014SummaryBeam Diagnostics are an exciting topic for research and ideal for training;Current performance limits shall be discussed at this workshop talks to stimulate discussion;There are still very significant challenges that will require close international collaboration.

Thanks for your attention !!

Prof. Carsten P. Welsch - oPAC Beam Diagnostics Workshop, May 2014