07 FRIB Beam Stopping Plans and Reaccelerated Beam Rate · 2020. 5. 8. · A. Villari, May 2020 Proposal Workshop - 07, Slide 5 Two experimental areas for reaccelerated beams •

This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics.

Antonio VillariReAccelerator Department Head

07FRIB Beam Stopping Plans and

Reaccelerated Beam Rate

Stopped and Reaccelerated beams experimental areasBeam stopping capabilities Reaccelerator (ReA) capabilities ReA6 project statusBeam estimate for stopped beams Program Advisory Committee 1

(PAC-1)Beam estimate for reaccelerated beams PAC-1Upgrades ongoingSummary / Conclusion

Agenda

A. Villari, May 2020 Proposal Workshop - 07, Slide 2

New experiments, equipment and accelerators• New gas stoppers• Expansion of the reaccelerator and associated equipment

Stopped and Reaccelerated Beams Program Continuous Expansion


Existing Existing Dec-2020

Experiments with Stopped BeamsExperimental Area


Major instrument installed• BECOLA – laser spectroscopy• LEBIT – high precision mass measurements

Two general purpose end stations for stopped beam experiments available

Experiments with Reaccelerated BeamsTwo Halls Dedicated to Two Energy Ranges


Two experimental areas for reaccelerated beams• ReA3 high-bay (0.3 – 6.0 MeV/u)• Rea6 vault (2.0 – 12.0 MeV/u)

ReA3 highbay• JENSA/SECAR is major instrument installed• Two general beam lines available

ReA6 vault• SOLARIS will be major instrument

installed (end 2020)• One general purpose end station

available

Stopping Gas Facilities Producing Rare Isotope Beams for Science


1st degrader

Wedge and 2nd Degrader Linear gas stopper

R = 1500

Advanced Cryogenic Gas Stopper

Stop Beam Using Linear Gas Stopper


Courtesy Guy Savard, Chandana SumithrarachchiGas Stopper built by ANL

Advanced Cryogenic Gas Stopper (ACGS) with improved performance compared to other linear stoppers: NSF-MRI funded• Novel geometry reduces space charge effects (>10x higher beam rate capability)• MSU-developed ion surfing technique for fast extraction (2x faster)• Cryogenic operation provides cleaner beams (in-situ gas purification)

Running since March 2019

Improving the Stopping Facility with ACGS


Major pieces of equipment available for experiments• JENSA/SECAR in ReA3• SOLARIS (HELIOS like and AT-TPC) in ReA6


ReA3 vault

ReA6 vault

ReA3 accelerator

ReA6 cryomodule

SECAR

SOLARIS

GP-1GP-2

GP-3Beams from 1+ sources or gas stopperand Cooler-Buncher

Overview of ReA3 and ReA6 Projection: December 2020

ReA3 main focus is associated to studies on nuclear astrophysics, collective and single particle properties of the nuclei and fusion close to the barrier ReA6 main focus will be nuclear structure; deep inelastic collisions

ReA3 and ReA6 Energy RangeFrom 300 keV/u to 12 MeV/u


0

2

4

6

8

10

12

14

2 3 4 5

E (M

eV/u

)

M/Q

Maximum energies of ReA3 and ReA6

ReA3ReA6

Electron Beam Ion Trap Charge Breeder


Beam In-Out

New RFQ replaced older version successfully• Possibility to work in CW• Extends the Q/A range to 1/5• Increases reliability

» New design and manufacturing process» Trapezoidal cells, reducing needed maximum voltage» Measured efficiency 85%

New ReA-RFQRunning


Resonance at 80.5MHz

Trapezoidal cells

Design 95% completedCryomodule placedBeam line optic

elements• Q-poles and Dipoles in

house• Steerers in fabrication• Most of supports in place

Other installations• Walls being built• Cabinets in house• Cable trays in house

ReA6 availability• Estimate December 2020

ReA6 Project Advancement


Estimates are based on current experienceRates are listed for a very large portion of the Segrè table, i.e.

about 5,000 isotopesNot included in rate estimates

• Fractionation of activity within various molecules (chemistry) is taken into account

• Depending on requested energy, best charge state (with maximum efficiency in the EBIT) cannot be used for reaccelerated beams

• Depending on the case, contamination of charge states forces using not the optimal charge state in the EBIT

Incident beam limitation adopted in the gas cell was not tested

Beam Intensity Estimates Full Disclosure


80 Isotopes Delivered by Gas Stoppers19 Isotopes Accelerated by ReA


Element Z A

V 23 44,46

Mn 25 60

Fe 26 51,52,53,62,63,67

Co 27 52,54,63,64,65,68,69,52

Ni 28 55,56

Cu 29 56,58,70

Ga 31 63,75,76

Ge 32 80

As 33 65,67

Se 34 71,72,83,84,86,87

Br 35 72,75,77,78,85

Kr 36 73

Rb 37 91,93

Element Z A

C 6 11

N 7 13

O 8 14

Na 11 21

Mg 12 22,23,29

Si 14 24,26,27

P 15 26,27,29

S 16 31,40,42

Cl 17 31,33,34,42,43,44,45,46

Ar 18 34,37,46

K 19 35,36,37,38,45,46,47

Ca 20 36,37,38,39

Linear gas stoppers (N4) used to stop rare ion isotopesEstimate includes three components

• Input FRIB-rate = F• Gas stopping efficiency = S• Gas extraction efficiency = E• Beam intensity for stopped ions: B = F.S.E

Stopping in gas using N4 monochromator systematics• Variation as a function of the Atomic number (Z)

Beam Intensity Estimate for Stopped Beams [1] PAC 1


Stopping efficiency: S = 0.0225.Z – 0.0666; S=0.1 for Z45

Experimental data from 85Br with 1.7E+7 pps shows gas stopper efficiency of about 25(10) %.• This is the highest injected intensity tested in ACGS• Adopted 25% as maximum efficiency• Adopted 75 ms as delay in the cell

» measured delay in wired carpet with internal ion source in test stand: 10 ms

Extraction (from gas) efficiency estimate from particle-in-cell• Confirms experimental result

Adopted for estimate • E=0.1 for 4

Estimate includes 4 components• Beam input in ReA (intensity of stopped beam) = B• Beam-Cooler-Buncher efficiency = CB• EBIT efficiency = EB• RFQ efficiency = RF• Transport efficiency = TR• Beam intensity of reaccelerated beams: ReA = B.CB.EB.RF.TR

Efficiency of the Beam-Cooler-Buncher adopted: CB = 0.8EBIT efficiency adopted (experimental)

• Z < 10; EB = 0.3• 10 < Z < 45; EB = 0.25• Z > 45 ; EB = 0.1

RFQ and transport• RF = 0.8• TR = 0.8

Beam Intensity Estimate for Reaccelerated Beams PAC 1


https://groups.nscl.msu.edu/frib/rates/fribrates.html

Example of Rate Estimate


https://groups.nscl.msu.edu/frib/rates/fribrates.html

Cyclotron Stopper• Higher efficiency for lighter ions due to accommodation of long stopping paths• Estimated beam rate capability 108/s

Status • Magnet construction complete and magnet energized to full field. • Carpets tested• System moved to final location in N2/N3• System needs to be integrated to LEB

Coming Upgrades – Cycstopper


Stopping simulation in the Cycstopper

Using CERN/ISOLDE Target-Ion-Source system• “Target” replaced by radioactive sample (relatively long living)• Design underway• Available during A1900 reconfiguration (pre-FRIB) and with FRIB providing

multi-user opportunities• Can be transformed in solid stopper system in the future

Coming Upgrades – Batch-mode


Specifications• Magnetic field for operation: 3.5 T• Electron beam current: 4 A• Beam intensity: 1010 ions/s • Stable ions and preparing for FRIB intensities

Coming Upgrades – High Current EBIS


Electron gun(4 A)

Electron collector (~ 50 kW)

Trap assembly &superconducting magnet

Source transferred from Brookhaven

Stopped and reaccelerated beam systems can be used in FRIB from commencement of user operationGas stoppers provide a variety of beams at low energies (keV)Reaccelerator provides beams from 300 keV/u to the maximum of 12

MeV/u for Q/A=1/2. Q/A varies from 1/5 to 1/2 Five end-lines at very low energy are available for experiments,

including LEBIT and BECOLA Five end-lines at reaccelerator energies are available for experiments,

including SECAR and SOLARISEstimated beam intensities about 5,000 isotopes are available

Summary and Conclusion


Backup


Design of the ACGSUnique and Novel Features Support Maintainability and High Performance


PT CoolersReduces gas contaminants

Segmented Push PlatesFor variable push fieldsAble to measure Bragg Peak

9 Bare Metal Wire-Carpet ModulesFor faster transport Ease of maintenance

Funnel and Mini-CarpetsSimplifies Geometry

ReAccelerator


1+ ions

q/A separator

RFQ

MHB

CM1 Re-buncherCM2 6 resonators Beta = 0.041

CM3 8 resonatorsBeta = 0.085

R = 500; 0.012 MeV/u

80.5 MHz standard16.1 MHz being commissioned

0.6 MeV/u

0.3 MeV/u < E < 6 MeV/uE = 12 x q/A for q/A 4

The ACGS Installed in Beam-Line


PT CoolersReduces gas contaminants

Segmented Push PlatesFor variable push fieldsAble to measure Bragg Peak

9 Bare Metal Wire-Carpet ModulesFor faster transport Ease of maintenance

Funnel andMini-CarpetsSimplifies Geometry

PAC-2 intensities consider reasonable improvement in gas stopper and EBIT• R&D proposal being submitted to improve beam rate capability and purity,

based on ACGS lessons learnt• Use of HCEBIS• Maximum rate capability: 1E+9 pps

Ultimate FRIB intensities consider improvement in all fronts• Maximum rate capability: 1E+10 pps• Faster breeding in a Super-EBIT• Higher gas pressure in the gas cell – Cycstopper and/or new linear cell

Solid stopper • Not considered in those estimates• Can provide a substantial enhancement of beam rates in selected cases

PAC-2 and Ultimate FRIB Intensities


Batch mode system provide multi-user capability with rare isotope ions• Available already in 2021• Using purchased radioactive samples• Using collected isotopes during FRIB

fast-beam operation

Helium-Jet ion source • Installed on N1 roof and isotope transport

tests successful• Ion source, mass separation, beam

transport, to be completed

Multi-User Capabilities


Helium-Jet system

PIC calculation


107 pps, 80GeP = 80 mbar @ room tempPush = 10 V/cm

07�FRIB Beam Stopping Plans and Reaccelerated Beam RateAgendaStopped and Reaccelerated Beams Program Continuous ExpansionExperiments with Stopped Beams�Experimental AreaExperiments with Reaccelerated Beams�Two Halls Dedicated to Two Energy RangesStopping Gas Facilities Producing Rare Isotope Beams for ScienceStop Beam Using Linear Gas StopperImproving the Stopping Facility with ACGSOverview of ReA3 and ReA6 �Projection: December 2020�ReA3 and ReA6 Energy Range�From 300 keV/u to 12 MeV/uElectron Beam Ion Trap Charge BreederNew ReA-RFQ�RunningReA6 Project AdvancementBeam Intensity Estimates Full Disclosure80 Isotopes Delivered by Gas Stoppers�19 Isotopes Accelerated by ReABeam Intensity Estimate for Stopped Beams [1] PAC 1Beam Intensity Estimate for Stopped Beams [2] PAC 1 Beam Intensity Estimate for Reaccelerated Beams PAC 1 Example of Rate EstimateComing Upgrades – CycstopperComing Upgrades – Batch-modeComing Upgrades – High Current EBISSummary and ConclusionBackupDesign of the ACGS�Unique and Novel Features Support Maintainability and High PerformanceReAccelerator The ACGS Installed in Beam-LinePAC-2 and Ultimate FRIB IntensitiesMulti-User CapabilitiesPIC calculation

Documents

07 FRIB Beam Stopping Plans and Reaccelerated Beam Rate · 2020. 5. 8. · A. Villari, May 2020 Proposal Workshop - 07, Slide 5 Two experimental areas for reaccelerated beams •