IRRADIATION EXPERIMENTS & FACILITIES AT BNL:BLIP & NSLS II

Peter Wanderer

Superconducting Magnet Division, BNL

WAMSDO – November 14, 2011

Brookhaven Linac Isotope Producer (BLIP)

Schedule: ~ 6 months/year (during RHIC operation) Principal task: isotope production for medical etc.

use (proton beam, 117 MeV). Simultaneous irradiation and isotope production by

increasing beam energy, placing irradiation target ahead of isotope production target• 117 Mev → 140, 160, 180, 202 MeV• Irradiation at room temperature

Alternative: irradiation target behind isotope target, for irradiation by neutrons and scattered protons.

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Proton Beam Profile

The BLIP proton beam cross-section deduced from a gamma scan of the activation foil irradiated with the samples. The grid is in mm.

The position of the three 1 cm segments in the beam cross sectionSection B sees a proton flux varying by less than ±5%

90 mm

90 m

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"A" "B" "C"0

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More BLIP info

Target holder interior dimensions ~ 100 mm wide, 100 mm high, 75 mm deep.

Two target holders per assembly. Target assembly immersed in water for cooling

(flow: 200 liters per minute). Current user: LBNE – materials for Project X.

• Long Baseline Neutrino Experiment – Abandoned gold mine northwest of Fermilab (DUSEL)

• Measurements (yield strength, stress, CTE) in hot cell at BNL

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Window & basket mounts moved up .437” relative to box mounts for improved beam alignment.

Basket mounts

Added .437” of material to this surfaceWindows machined integral to box

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Windows machined integral to box

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Sample and Irradiation Details of 4 mm wide YBCO conductor

7 cm long samples were mounted on five aluminum frames and inserted into the water-filled target tank of the Brookhaven Linac Isotope Producer (BLIP).

The irradiation was done at 142 MeV with a beam current of 40 μA, and different levels of proton flux were achieved by progressively removing the aluminum frames after specific times to give 2.5, 25, 50, 75, and 100 μA-hrs of irradiation.

100 μA-hrs is equivalent to a fluence of 3.4x1017cm-2

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Experiment

courtesy G.Greene and B.Sampson

Voltage taps

I

HTS sample is under the G-10 cover

Three 1cm sections of each conductor are measured.

YBCO samples are irradiated at the Brookhaven Linac Isotope Producer (BLIP) (G.Greene)

Levels of proton fluence are 2.5, 25, 100 mA hrs.

B is positioned to be at the center of the beam. Open cryostat. Samples are directly cooled by

LN2. Magnetic field (0.25T, 0.5T,0.75T, 1.0T and

1.25T) are provided by a non-superconducting magnet.

Angle=0:

The normal to the tape plane is parallel to the external magnetic field

Rel.dose=25 In actual FRIB system, estimated rel.dose would be ~10.

rel.dose=25 is close to the actual dose. Ic of rel.dose=25 was expected to be between Ic of

rel.dose=100(highest) and rel.dose=2.5 (lowest). However…

Angular dependence of ASC sample on Ic at various dose levels at 1T

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angle(deg)

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rel.dose=100

ASC SuperPower

Ic vs magnetic field

As field increases, Ic decreases monotonically for any radiated samples.

Rel.dose=25 gives slightly higher Ic than rel.dose=2.5 in

some magnetic fields. This effect is clear in SuperPower sample but not in ASC sample.

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ASC90 deg

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ASC SuperPower

Measured Ic at 77K, self field

As radiation dose increases, Ic decreases monotonicallyfor both ASC and SuperPower YBCO samples

Critical current (Ic) of samples was measured before and after irradiation at 77 K, self field.

Ic of all samples before radiation was ~100 A.

(courtesy G. Greene and W. Sampson)

Radiation Damage Studies on YBCO by 142 MeV Protons by G. Greene and W. Sampson at BNL (2007-2008)

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Radiation Dose (mA.Hours)

I c (I

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SuperPower Sample#1SuperPower Sample#2

SuperPower AverageASC Sample#1ASC Sample#2

ASC Average

100 mA.hr dose is ~ 3.4 X 1017 protons/cm2 (current and dose scale linearly)

Ic Measurements at 77 K, self field

Ic of all original (before irradiation) was ~100 Amp

Ramesh Gupta, BNL 3/2008

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YBCO and Nb3Sn

YBCO (High Temperature Superconductor)• Target cooled off to “no detectable radioactivity”. Had

surface contamination. → Test in dewar in “clean” area, behind “caution” tape and sign (i.e., not in hot cell)

• Annealing varied with dose (low dose → no anneal)• Not production material.

Nb3Sn – ITER material• Annealing at room temperature not significant.

Nb – “pure Nb has 600 ppm Ta – long-lived radioisotopes after irradiation.

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PROPOSED ENDSTATION FOR NEW BNL LIGHT SOURCE, NSLS II

Endstation for radioactive materials• 30 – 80 keV monochromatic photons• Beam diameter: 10 μm• Techniques: Diffraction, imaging

Endstation for real-time, in situ studies w. photons• 1 MeV tandem for heavy ions• 200 kV accelerator for H, He• Ion beam diameter: μm to mm• Time resolution: μs to ms

Supporting infrastructure Presentation to Advisory Committee 17 Nov.

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Credits

BLIP: L. Mausner, A. Ghosh YBCO measurements: R. Gupta, G. Greene, W.

Sampson, Y. Shiroyanagi NSLS II: A. Ghosh, L. Ecker

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Real time and in-situ studies of Materials in a Radiation Environment (MRE)

MRE at NSLS II• Ion accelerators for in situ experiments of radiation

effects and mesoscale microstructural changes due to radiation

• Separate endstation for radioactive materials• Will enable studies of new materials for reactors,

nuclear fuels and structural materials in high radiation environments

• Data for verification of computer simulations, material performance during off-nominal conditions, and licensing

Examples of Science Areas & Impact• NUCLEAR STRUCTURAL MATERIALS: Role of

interfaces in radiation resistant materials• NUCLEAR FUELS: Characterization of spent fuel,

metal fuels, and new synthesis routes for oxide fuels • NATIONAL SECURITY: material characterization for

nuclear forensics• SEMICONDUCTOR FABRICATION: Understand the

effect of doping induced defects on semiconductor performance

Beamline CapabilitiesTechniques: Diffraction, Imaging, SpectroscopySource: Damping or superconducting wigglerEnergy range: 10-90 keVTime resolution: msec-µsecBeam Size: > 1 µm

Displacement Cascade Near a Grain BoundaryBai, et al. Science, 2010