Laser-Based Beam Diagnostics R&D for Project X

Beam Diagnostics ChallengesWim Blokland ORNL / SNSDave Johnson, Peter Prieto, Gianni Tassotto, Randy Thurman-Keup, Vic Scarpine, Dan Schoo, Dave Slimmer, Duane Voy, Arden Warner, Manfred Wendt, Jim Zagel, and many others FermilabPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)1Beam Instrumentation at FermilabAD-Instrumentation Department activities~30 techs, EEs and accelerator physicistsOperation, maintenance, improvements on RunII, NuMI, SY (M-Test) and many other beam diagnostics (>1000 units).Support upcoming projects and facilities, NoVA, proton improvement plan, HINS (MDB), ILC-TA (NML), mu2e, g-2,R&D for future projects and facilities, e.g. Project X, still a little bit ILC, various collaboration activities. Good foundation for standard beam instrumentsRead-out systems applying digital signal processing techniques for beam intensity and orbit (BPM) monitoringIntegrated calibration techniques.Many improvements on beam profile monitors, e.g. SEMs. Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)The High Beam Power ChallengeFermilabs intensity frontier future requires High beam power, today ~300 kW (NuMI), soon ~700 kW (NOvA), in the future > 2 MW (Project X).Non or minimum invasive beam diagnostics detectors with low residual losses.Possible solutions:It is simple (solved) for electromagnetic beam detectors (toroids, WCM, BPM).Not trivial for transverse beam profile (emittance) measurements!Flying or scanning wires, SEM mulitwires: invasive.Ionization profile monitor (IPM) based on residual gas.Laser wire photo-detachment (requires H- beams)Electron-beam scanner. Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)SEM Multiwire

thermal simulation 5 m strip, 260 kWUT/ Fermilab multiwire SEMsUsed in NuMI, and other beam-linesTi strips (5x125 m), wires (25 m dia.), 1.0 / 0.5 mm pitch. Carbon monofilament SEM R&D (PM118)Reduce residual losses (low Z material), greater wire heating capability.33 m diameter carbon monofilament, density 1.8 g/cm3, 12 g tension, 1 mm pitch

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)SEM Mulitwire (cont.)

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)Ionization Profile Monitor (IPM)

Based on the ionization of the residual gasp or pbar collisionsGas molecule -> ion + eCollect eitherIonsSubject to space chargeor ElectronsNeeds magnetic a guidefield, such that the spin diameter < detector strip widthUsed for turn-by-turn measurementsBooster: 2.25 1.5 secMI: 11.1 secTeV: 21 sec (also single bunch) Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)MI IPM Injection Oscillations

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)MI IPM Installation

MCP and field shaping assembly lifted to show copper pick-up strips.Permanent magnet @ 1kG10 kV clearing fieldPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)IPM vs. Flying Wire

Left: Flying WireRight: H2IPMLeft peak: pbar RR -> TeVRight peak: pbar ACC - > RR

Sigma for H2IPM and FWPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)Laser Wire for H- BeamsE or BH-H- +H- + H0e-F-CupLaser beamGalvanometerH- BeamLaser Beam

H- neutralization by photo-detachmentCross-section max 4.2x10-17cm2 Electron binding E0 = 0.7543 eVTypical HINS / PX MEBT parametersEbeam = 2.5 MeV, Nd:YAG laser 1064 nm,900 angle, -> 3.66x10-17 cm2Requires laser energy ~ 10-30 mJ

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)MI-8 Laser WireLaser Profile Monitor detailsQ-switch laserLaser energy: 50 mJouleWavelength: 1064 nmPulse length: 9 nsecFast rotating mirrors (40 / 100 sec)e- detector: scintillator & PMT

optical boxlaser beamH- beamdouble dipoleBPMBPMdetector port

First horizontalprofile scan! Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)MI-8 Laser Wire Optics

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)Electron-Beam ScannerNon-intrusive profile measurement of high intensity p-beamsSNS / Fermilab R&D collaboration for Project X, beams in MIEvaluate measurement techniques for available electron gunSetup simulationLook at the deflected projection of a tilted sheet of electrons due to the proton beam charge [1,2,3]Neglect magnetic field (small displacement of projection)Assume path of electrons is straight (they are almost straight)Assume net electron energy change is zero (if symmetric)Proton bunch length >> electron scan

i.e. take the derivative to get the profile

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)E-Beam Scanner (cont.)Deflection optionsCavity or other fast deflectorSheet beam

5-10 GHzDeflectorsScrapersSXYprotonselectronsddx

Cathode

GateQuadrupole(s)ScrapersSXYprotonselectronsddx

Cathode

GateXXXXPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)E-Beam Scanner Test Setup at NWAGun ParametersEnergy: 1 60 keVCurrent: 10 A 6 mASpot size: 50 m 10 mmGateable: 2 s DC; 5 kHz max rate

Electron GunEGH-6210Gun SolenoidActuatorsFaraday Cup / DumpX2X1Firewire Cameras

Cave at NWAPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)Low Beam Intensity Challenge

2e extinction measurement:Beam: 3.7x107 p / bunch (3.5 A, 25 kW)No beam: single particle count in the search window (~0.2 pA), with 20 nsec time resolution.Possible Solution: SQUID-basedCryogenic Current Comparator (CCC)Successfully operation at GSI and elsewhereSC shield & coil, plus high performance SQUIDMeasurement in the flux quantum regimeRequires exceptional effective shielding

beamcurrentPage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)SQUID FB ElectronicsExample (~10 years old):UJ 111 DC-SQUID performanceBandwidth: DC-70 kHzSensitivity: 167 nA / 0Flux noise: 8x10-5 0 /HzCurrent noise: 13 pA /Hz

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)

Superconducting Quantum Interference DevicePage #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt) SQUID Array Sensors DC SQUIDs (i.e based on two Josephson junctions)

We are exploring a new family of robust low noise SQUID devices that are optimized for operation with a high-speed direct coupled flux-locked loop (FLL).

Some main Features:

Series array of SQUIDS with < 3 nH input inductance.

A current noise level of 9 pA/(Hz)1/2 at 4.2 K

Ultra high speed operation was demonstrated using FLL electronics in close proximity to the SQUID array

FLL bandwidth of 350 MHz achieved, more than an order of magnitude better than others before

For Applications requiring larger input inductance (up to 2 H) two stage sensors were developed consisting of a single front-end SQUID with double transformer coupling read-out by a SQUID array)

The voltage-flux characteristics of the arrays are reported to be single-SQUID-like with coupled energy resolution ~ 50 h (50 times Plancks constant)

Reference: IEEE Trans. Appl. Supercond. 17 (2007) also direct conversation with Dietmar Drung of PTB, Germany.

Important figure of merit for SQUID current sensors: Coupled energy resolution : c = SI Lin /2 ( where SI is input referred noise and Lin is input inductance)According to the theory a well coupled dc-SQUID should have an energy resolution below 20 times Plancks constant h.

However in practice : A coupled dc-SQUID generally have a higher noise level than predicted by simple theory; A coupled energy resolution below 100 h at 4.2 K is difficult to achieve with high Lin SQUIDs. For the DESY CCC coupling = 543 h

Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)Thank You!Page #May 5, 2011 Fermilab Detector Retreat Beam Diagnostics (M. Wendt)