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Compact Single-stage �

Superconducting Cyclotron-based Primary Accelerators �

Timothy A. Antaya, Leslie Bromberg, Eric Forton, �Joseph Minervini, Mark Norsworthy, Jordi Reig and Makoto

Takaysu�

MIT Plasma Science and Fusion Center�

DAEdALUS Workshop – MIT LNS – 4 February 2010 �

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Present Collaborators & Research Areas�  MIT Plasma Science and Fusion Center FTED - Minervini, Bromberg & Students�

  Advanced magnet technology and engineering for cyclotrons: NbTi, Nb3Sn, HTS�  Frontier Studies DOD DTRA- High Intensity High Energy Sc Cyclotrons�

  MIT Nuclear Science and Engineering - Dick Lanza & students�  Near Proximity Proton Transmission imaging (Radiography) of Strategic Nuclear Materials (SNM)�  Radiological Source Replacement �  SPECT and Short Lived PET Isotopes�

  Los Alamos National Laboratory (LANSCE) - Rich Sheffield, Chris Morris�  Near proximity detection of shielded SNM �  Proton Radiography at 250-500 MeV �

  Raytheon IDS Advanced Technology Group - Brandon Blackburn, Bernie Harris, Mike Hynes �  Nanotron- Deployable van based SNM scanner �  ISIS- 60 MeV Linac for first generation 100m stand-off Photon Active Interrogation �

  University Strategic Partnership [PSU/UNM/OU] - Dan Merdes (PSU)�  Aquatron - a UUV based cyclotron for below water level vessel inspection �

  CIEMAT - Madrid,Spain - Diego Obrador, Luis Garcia-Tabares�  16 MeV 6T Cyclotron PET Cyclotron �  Technofusion: 110 MeV/A heavy ion cyclotron for Fusion Materials Testing �

  Indiana Univ - Vladimir Anferov and ProCure- John Cameron and Mark Leuscher�  Double Bend Momentum Achromatic Sc Gantry for PBRT �

  IBA - Yves Jongen and Eric Forton �  Compact High Rigidity Sc Magnets for Hadron Therapy�

  Daedalus (MIT/Columbia) W.Barletta, J,Conrad, P. Fischer, S. Kopp, R. Lanza, M. Sheavitz�  Compact GeV Cyclotron Array for a search for CP Violation in the Neutrino Sector �

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WMD Sensing at long range via high energy accelerators: �

  Active interrogation- use a primary beam (protons) to produce a secondary beam: �

  GeV protons have a range of a few km in air�

  They make numerous nuclear reactions in air, surrounding material and HEU which ultimately stimulates fission in HEU �

  Stimulated fission has characteristic radiation which one detects allowing a positive ID of the suspected material�

  High intensity required: it's a r-2 × r-2 problem�

  The final system should be deployable�

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Our approach to this challenge is to significantly advance the interrogation source: �

  Involved in a set research efforts to address the feasibility and limits of: �

  Compact (a few cubic meters)�

  Transportable (minimize the mass and power)�

  Single stage (only one accelerator)�

  High Field Superconducting Cyclotron (>7T)�

  For protons at �  High Energy (>2 GeV)�  High Intensity (>2 mA)�

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CSC Proton Active Interrogation Source: �

  Compact (a few cubic meters)�

  Transportable (minimize the mass and power)�

  Single stage (only one accelerator)�

  High Field Superconducting Cyclotron (>7T)�

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A 7T Sc Cyclotron compared with PSI �

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Or�

  7T Sc Cyclotron Compared with LANSCE�

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Why Cyclotrons?�

  Cyclotrons are efficient users of acceleration voltage (MV/m E-fields not required to reach high energy)�

  Cyclotrons have been around for 8 decades and are well characterized and quantitative�

  Superconducting cyclotrons have been around for 3 decades, are robust, and have established a scaling in which plant cost decreases 3x when the B field is approximately doubled�

  Superconducting Cyclotrons have never required feasibility demonstrations: beam dynamics and magnet designs are quantitative and predictive�

  It is now possible to again double the B field without increasing risk or diminishing performance�

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SOA for High Energy/Power Proton Accelerators �

  Highest performance is a cyclotron �

  None of these machines are compact or transportable�

Machine� Type� Energy (MeV)�

Intensity (mA)�

Power (MW)�

Stages�

PSI � Separated Sector Cyclotron (2000 tons; Bave~0.5T, 1974)�

590 � 2.2 �(goal is 3.0)�

1.3� 3: 0.87 MeV; 72 MeV;590 MeV �

LANSE� Resistive LINAC (400m; 1972) �

800 � 1.2� 1 � 3: 0.75 MeV; 200 MeV; 800 MeV �

SNS� Resistive & Superconducting LINAC (1000m, 2003)�

1000 � 1.0 �

(goal is 1.4) �

1.0 � 6: IS; 2.5 MeV; (DTL-CCL-SCL); 1000 MeV; A-Ring �

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SOA for Compact High Power Proton Accelerators�

  All of these are low energy machines�  None are particularly transportable�  These machines are generally limited by beam losses due to

halo formation around the central beam�

Machine� Type� Energy (MeV)�

Intensity (mA)�

Power (MW)�

LEDA � LINAC (front end for APT)�

6.7 � 100 � 0.7 �

GTA � LINAC (demo for full GTA accelerator)�

3.2 � 32 � 0.1 �

IBA Cyclone 14 � Cyclotron �(elliptical pole, self-extracted beam channel)�

14 � 15 �(internal only- main probe

melted pushing limit; 2.5 mA external @

90% ext. effic.)�

0.2 �

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So Called ‘Next Generation’ Compact Accelerators ?�

Laser Plasma

Dielectric Wall Accelerator

FFAGs? No! will always bigger and more expensive than isochronous cyclotrons while beam dynamics is more complex and less well developed

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So Called ‘Next Generation’ Compact Accelerators ?�

Lasers? No! these are science experiments

DWA? No! is a stars wars experiment

FFAGs? No! will always bigger and more expensive than isochronous cyclotrons while beam dynamics is more complex and less well developed

None of these will every be more compact or less expensive than a high field superconducting synchrocyclotron that fits inside the hole that makes a SSC a FFAG �

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We exploit: Cyclotrons can be made very compact by going to high magnetic fields (Ef≈Kr2B2). �

B (T) � Final Radius

(m)�

Size Decreases

by: �

1 � 2.28 � 1 �

3 � 0.76 � 1/27�

5 � 0.46 � 1/125�

7 � 0.33 � 1/343�

9 � 0.25 � 1/729�

An efficient cyclotron electromagnetic structure is almost spherical- the size then scales inversely and cubically with increasing field for a given ion and final energy.

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Superconducting Isochronous Cyclotrons-- in their 3rd decade of use�

  MSU K500 – 1982 �  Solved field design problem�  Solved 3-phase RF�  Solved beam extraction �

  MSU K1200 – 1988�  highest energy CW accelerator�

  TAMU K500 – 1988 �  improved RF mech. design �

  MSU K100 – 1989�  Solved gantry rotation with pool boiling

cryogens�  C.R. w/ separated cathode PIG �

  Milan/Catania K800 - 1994 �  booster �

  Orsay/Groningen K600 - 1996 �  heavy ions and protons�

  Accel/MSU K250s- PBRT 2005-6 �  two built and commissioned simultan.�

These machines have: �  Establish important technol. limits @4-6T �  Eliminated model magnets and shimming �  Lower overall power and size�  As a class are very robust �  Cryogenics- many options�

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Resources: historical achievements, field scaling, cyclotron beam physics and technology advances �

  1.0 GeV has been done in a cyclotron (Petersburg)�

  >1 mA extracted beam intensity has been done in a single stage cyclotron �

  Compact Superconducting Cyclotrons have been built to 1.2 GeV proton field strength (1.6 GeV is now in progress)�

  Bright external ion sources: 40 mA < 0.1 mm-mrad norm. emittance�

  3 decades of Sc magnet technology advances: conductors, winding packs, cooling, structures, protection, simulation �

  Significant advances in quantitative beam dynamics: central regions, acceleration, resonance crossing, extraction, phase space evolution, transverse and longitudinal space charge�

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An Example: MIT Designed Still River Monarch 250 MeV Proton Cyclotron for Proton Beam Radiotherapy�

  Cost of PBRT is reduced an order of magnitude ($150M to $20M)�

  First system goes into Hospital June 2010 �

  5 are in various stages of production simultaneously�

  15 are on order�

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Back to the High Energy Machines – two efforts are central to DAEdALUS: �

DTRA Frontier Studies – in progress�

DOD High Intensity Demo Cyclotron – just starting�

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Frontier Studies of Single-stage �

Superconducting Cyclotron-based Primary�

Accelerators �

for Sensing Fissile Materials at Long Range�

DTRA Grant HDTRA1-09-01-00042 �

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Frontier Studies of Single Stage Superconducting Cyclotron-based Primary Accelerators for Sensing Fissile Materials at Long Range, T Antaya, L

Bromberg and J Minervini, MIT, HDTRA1-09-01-00042 �

Status of effort: High intensity test stand hardware design in progress. Beam simulations just starting. Rare earth ferromagnetic materials testing Fall 2009.

Personnel Supported: 3 senior research staff and 2 engineering staff; 1 full time graduate thesis student; multiple undergraduate research participants planned

Publications & Meetings:

none in past 12 months.

Key Milestones: • FY09: 2 GeV Cyclotron Design; High Field Test Stand Assembly; Gadolinium Magnetization test • FY10: Iron-free Cyclotron- establish limits; Proton ECR Ion Source testing • FY11: High Temp Superconductor Cyclotron- est. limits; Beam Inflection Intensity at high field limit Funding Profile: FY09: $0.400M; FY10: $0.416M FY11: $0.433M PI Contact information: Timothy Antaya, 617-253-8155, antaya@psfc.mit.edu

Description of Effort: Rapid long range WMD sensing requires multi-mA Proton Beams at multi-GeV energies. We will conduct a quantitative study of the fundamental feasibility of a compact single stage high field superconducting cyclotron to meet this need.

Challenges: •  High Energy Proton Cyclotron Acceleration

Limit Determination (> 2 GeV) •  High Intensity Limit Determination for a Single

Stage Proton Cyclotron (> 2 mA)

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A Target Design 'Strawman': A 1 GeV Protons at 6T Transportable Compact Superconducting Cyclotron �

We have some well defined work to do: protons, 'compactness', high energy/high intensity, single stage- must be combined�

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There are 3 basic problems to be addressed: �

  Cyclotron Design (Beam Dynamics at high magnetic field) �  In general there is nothing special about field strength-

cyclotrons operate over a factor of 8 range in field now �  Codes are quantitative and predictive (since 1950s) and

simulations alone are sufficient �  We have to show that the most sensitive issues are addressed

appropriately at high γ �  [Isochronous] Cyclotron Magnet Topologies at High Field�

  In cyclotrons, it's all about the field design �  magnet needs to be simplified and new structure for flutter

must be introduced to further 'compactness' �  High Intensity�

  ion source brightness, initial beam formation, acceleration and extraction all must match precisely�

  data from an ion source test stand is needed to assist in this process�

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Y1 - GeV Cyclotron Design �

  Looking first at 1 GeV - have already a reasonable design: �  peak pole field 7T �  pole radius ~70 cm�  6 sector - 3 dees in valleys�  third harmonic acceleration- allows about MeV/turn

energy gain with with dee voltage of 150 kV �  Mass of about 90t �

  Essentially the K500 at MSU - a 5.5T peak field Sc Cyclotron commissioned in 1982 �

  Next Step - 3D field design for an analysis of the equilibrium orbits and the betatron tunes �

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Y1 - Magnet Topologies for Compactness�

  Want to have a look at replacing the pole tip iron with Rare Earth Ferromagnetic materials - Why?�  Mosts interested in Gd and Ho but we may look at Dy

and Er as well�  They have saturation magnetizations of 2.5-3T at low

temperatures�  The cyclotron magnet can be cold in this new class of

CSCs �  We can use Sc coils for the flutter as well but the REFs

are 'passive' magnetic flux concentrators�  They are expensive ($300-1000/kg) but so are

superconductors ($200-$3000/kg) �  Engineering? We need sufficiently smooth B v. H

data for our 3D field modeling codes - none is available�

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We are going to measure B v. H curves ourselves! �

  Mark Norsworthy MIT SM Degree June 2010 �

  Use an existing could bore 14T magnet normally used to measure properties of new superconductors�

  4.2K Cold Specimen holder design �

  Gadolinium first then Holmium �

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High Intensity: Establish a High Field Cyclotron Central Region Test Stand�

  We know the needed starting parameters for high extraction efficiency from a CSC at high intensity: �  2mm-mrad transverse emittance (no work 10 mm-mrad)�  5°longitudinal phase width (no work 15-20°)�  0.01% energy spread (no work 0.1%)�

  Cyclotrons are operating with mA internal currents (no work 75% extraction efficiency)�

  'Predictive' beam simulations with space charge at high field must be done �

  Benchmarked codes exist: �  VPAC - used to design the 9T PBRT cyclotron �  BEAM3D - used to solve the high space charge injection

problem in cyclotrons�  We need experimental data to compare with simulations- in

cyclotrons space charge effects happen mostly in the cyclotron Center�

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9T High Intensity Proton Ion Source Test Stand�

  40 mA, 0.01 mm-mrad Proton ECR Ion source at 20 kV (J. Reig Thesis)�

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Frontier Studies Expected Outcomes - Year 1 �

  Baseline cyclotron design for systems and applications studies�

  New pole structures for passive high field isochronous cyclotron field designs (and probably also many other kinds of beam transport magnets)�

  High field ion source test stand for High Brightness Proton Beams to support the stand-lone configuration �

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250 MeV, 1 mA Demo Cyclotron �

  Frontier Studies is a ‘methodical’ fundamental beam science research program�

  We were asked in late Oct 2009 to propose a fast demonstration experiment �

  Parameters: �  3y design and build�  Compact, transportable & operable in a remote location �  Address all the fundamental and engineering feasibility

issues associated with high intensity, radiation �  High extraction efficiency�

  And… it must work! �

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Properties�

  4 Sector Superconducting Isochronous cyclotron �

  B0≈5.6T, Bf≈7T �

  Rpole ≈0.4m ; 37 tons�

  84.5 MHz, h=1, 2 dees in valleys, V0 ≈ 160 kV; 450 kW �

  External ECR and axial injection �

  Non-resonant extraction; passive magnetic channels�

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Status�

  Its Fast- need a deep team: MIT, MSU, GA and Raytheon �

  Baseline Design is in Progress�

  Engineering Start ~ mid-march�

  International External Feasibility Review at + months�  Skeptics are welcome to apply as reviewers and I’ll

forward your names along �

Thank you! �