Studies of Muon-Induced Radioactivity at NuMI Radioactivity at NuMI - - PowerPoint PPT Presentation

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Studies of Muon-Induced Radioactivity at NuMI Radioactivity at NuMI David Boehnlein Fermi National Accelerator Laboratory (on behalf of the JASMIN Collaboration) NuFact09 July 24, 2009 NuFact09 July 24, 2009 The JASMIN Collaboration

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SLIDE 1

Studies of Muon-Induced Radioactivity at NuMI Radioactivity at NuMI

David Boehnlein Fermi National Accelerator Laboratory (on behalf of the JASMIN Collaboration) NuFact09 – July 24, 2009 NuFact09 July 24, 2009

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SLIDE 2

The JASMIN Collaboration

  • D. J. Boehnlein, A. F. Leveling, N. V. Mokhov*, K. Vaziri
  • Fermi National Accelerator Laboratory
  • Y. Iwamoto, Y. Kasugai, N. Matsuda, H. Nakashima*, Y. Sakamoto*
  • Japan Atomic Energy Agency
  • M. Hagiwara, Hiroshi Iwase, N. Kinoshita, H. Matsumura, T. Sanami, A. Toyoda
  • High Energy Accelerator Research Organization (KEK)
  • H Yashima
  • H. Yashima
  • Kyoto University Research Reactor Institute
  • H. Arakawa, N. Shigyo
  • Kyushu University
  • H. S. Lee
  • Pohang Accelerator Laboratory
  • K. Oishi
  • Shimizu Corporation

p

  • T. Nakamura
  • Tohoku University
  • Noriaki Nakao

A Illi i

  • Aurora, Illinois

* Co-Spokesperson July 24, 2009 NuFact09 - David Boehnlein 2 NuFact09 - David Boehnlein 2

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SLIDE 3

The JASMIN Experiment

  • JASMIN – Japanese & American Study of

Muon Interactions and Neutron Detection Muon Interactions and Neutron Detection (Fermilab T972)

  • A study of shielding and radiation physics

effects at high-energy accelerators

  • Studies to date have focused on the anti-

proton production target (AP0) and NuMI. p oto p oduct o ta get ( 0) a d u

  • We present here status of work in

progress to study activation at the NuMI progress to study activation at the NuMI muon alcoves.

July 24, 2009 NuFact09 - David Boehnlein 3 NuFact09 - David Boehnlein 3

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SLIDE 4

Experimental Goals of JASMIN

  • Benchmarking of Monte Carlo codes
  • Radiation safety

St d f i t ti

  • Study of muon interactions
  • Material activation
  • Shielding
  • Muon detection & measurement
  • Improved characterization of NuMI
  • Improved characterization of NuMI

muon monitors.

July 24, 2009 NuFact09 - David Boehnlein 4 July 24, 2009 NuFact09 - David Boehnlein 4

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SLIDE 5

Motivation

  • Why is a neutrino experimenter talking to

a group of accelerator physicists about a group of accelerator physicists about radiation physics?

  • This workshop is considering machines

that could produce unprecedented muon intensities.

  • If such machines are to be built, one must

suc ac es a e to be bu t, o e ust consider the radiological issues, including the potential for radioactivation c ud g t e pote t a

  • ad oact

at o due to muons.

  • Monte Carlo codes used for simulations

July 24, 2009 NuFact09 - David Boehnlein 5 NuFact09 - David Boehnlein 5

  • Monte Carlo codes used for simulations

should accurately account for it.

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SLIDE 6

Source of electron, photon and neutron

Photo nuclear reaction A

n   e-

A

e+

Bremsstrahlung Electro-magnetic cascade Bremsstrahlung Pair production

Radiations around intense muon beam (T Sanami)

Pair production

July 24, 2009 NuFact09 - David Boehnlein 6 Radiations around intense muon beam (T.Sanami)

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SLIDE 7

Neutrinos at the Main Injector

  • The NuMI beamline focuses a νμ beam toward

Soudan, Minnesota. Soudan, Minnesota.

  • Since the neutrinos come from 2-body pion

decay, the world’s most intense neutrino beam is l th ld’ t i t b also the world’s most intense muon beam.

  • Arrays of ionization chambers in downstream

alcoves monitor muons co-produced with the

July 24, 2009 NuFact09 - David Boehnlein 7 July 24, 2009 NuFact09 - David Boehnlein 7

alcoves monitor muons co produced with the neutrinos.

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SLIDE 8

NuMI Muon Monitoring Alcoves

muons

Decay pipe

muons

Abs

  • rber

Alcove-4 Alcove-1 Alcove-2 Alcove-3 0 m 13.7 m 33.5 m 67.1 m Alcove-0

S f

  • Schematic layout of the muon alcoves at

NuMI

  • Note that Alcove 1 is in the Absorber Hall.
  • See L. Loiacono’s talk at this workshop

July 24, 2009 NuFact09 - David Boehnlein 8 July 24, 2009 NuFact09 - David Boehnlein 8

See L. Loiacono s talk at this workshop for a discussion of the muon monitors.

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SLIDE 9

Estimated Muon Fields

Alcove Charged Particle Fluence Beam Size Fluence 1 6.5 x 105cm-210-12ppp 190 cm 2 0.9 x 105cm-210-12ppp 250 cm 3 0.35 x 105cm-210-

12ppp

190 cm

  • Predicted data from Kopp et al. [NIM A 568 (2006)503]
  • Assumes Low Energy Beam
  • Assumes Low-Energy Beam.
  • Beam size is FWHM.
  • Neutrons < 1% in downstream alcoves.

July 24, 2009 NuFact09 - David Boehnlein 9 July 24, 2009 NuFact09 - David Boehnlein 9

Neutrons < 1% in downstream alcoves.

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SLIDE 10

Procedure I

  • Copper and

Aluminum disks were placed in alcoves 1 -4.

  • Disks are 8 cm

Disks are 8 cm diameter x 1 cm thick.

  • Beam exposure was

Beam exposure was 22.8 hours.

  • NuMI beam put 6 26 x

NuMI beam put 6.26 x 1017 p.o.t.

  • Additional samples

Additional samples were placed to measure neutron

July 24, 2009 NuFact09 - David Boehnlein 10 July 24, 2009 NuFact09 - David Boehnlein 10

activation.

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SLIDE 11

Procedure II

  • JASMIN operates parasitically with

NuMI NuMI.

  • Samples are placed and retrieved

Samples are placed and retrieved during natural beam-down periods.

  • Isotopic signatures are measured on

High-Purity Ge counters at High- g y g Intensity Lab. O i f h d i

  • Operations so far have occured in

November 2007 and November 2008.

July 24, 2009 NuFact09 - David Boehnlein 11 July 24, 2009 NuFact09 - David Boehnlein 11

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SLIDE 12

Radionuclides observed in Samples Samples

  • This table

summarizes the summarizes the radionclides

  • bserved in the

exposed copper samples.

  • 54Mn, 57Co, 60Co

have substantial half-lives (beyond a reasonable cool- d i d f down period for accelerator maintenance)

July 24, 2009 NuFact09 - David Boehnlein 12

maintenance).

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SLIDE 13

Preliminary Results

  • Attenuation of muons,

as shown by yield y y ratios normalized to Alcove 2.

  • Yield ratios vs.

distance (top)

  • Yield ratios vs.

nucleons emitted from target nucleus (bottom)

  • Note Aluminum

results are included (24N )

July 24, 2009 NuFact09 - David Boehnlein 13 July 24, 2009 NuFact09 - David Boehnlein 13

(24Na).

  • Figures courtesy of H.

M t

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SLIDE 14

Preliminary Results II

  • Activation Products
  • n copper samples by

10-33 10-32

  • ton-1)

Alcove-1

pp p y mass number.

  • Alcove 1 shows

10-35 10-34

yields (atom-1 pro

Alcove 1 shows evidence of neutron activation.

20 30 40 50 60 10-37 10-36

Product mass number Mass y

  • The narrow line is a fit

to an empirical

Product mass number

10-34 10-33

  • 1)

Alcove-2

Experimental MARS15

formula for photospallation (Rudstam et al Phys

10-36 10-35 10 34

ds (atom-1 proton

MARS15

(Rudstam et al. Phys Rev 126, 5 (1962) 1852).

10-38 10-37 10

Mass yield

July 24, 2009 NuFact09 - David Boehnlein 14 July 24, 2009 NuFact09 - David Boehnlein 14

1852).

  • The lower plot

histogram is a

35 40 45 50 55 60 65 10

Product mass number

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SLIDE 15

Summary

  • JASMIN has measured radionuclides

produced in Aluminum and copper produced in Aluminum and copper in the muon alcoves

  • It’s not clear how much of the

activity is produced by muons and how much by muon-produced neutrons (for radiation safety, does it ( y matter?)

  • MARS15 simulations give good
  • MARS15 simulations give good

predictions of dose rates and activation

July 24, 2009 NuFact09 - David Boehnlein 15 July 24, 2009 NuFact09 - David Boehnlein 15

activation.

  • Studies will continue in Fall 2009.
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SLIDE 16

Backup Slides . . .

July 24, 2009 NuFact09 - David Boehnlein 16

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SLIDE 17

ACNET Readout for Exposure

July 24, 2009 NuFact09 - David Boehnlein 17 July 24, 2009 NuFact09 - David Boehnlein 17

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SLIDE 18

10-7 10-6

)

Alcove-1 Alcove-2 Alcove-3 Alcove 4

10-9 10-8

m-2 proton-1)

Alcove-4

10-11 10-10

x (GeV-1 cm

6 8

proton-1) x 10-8

10-13 10-12

Muon flux

2 4 6

n flux (GeV-1 cm-2 p

10-1 100 101 102 10-15 10-14

Energy (GeV)

2 4 6 8 10

Energy (GeV) Muon

Energy (GeV)

  • FIG. Calculated muon spectra in units of number
  • f muons per GeV, per cm2, and per primary

proton in Alcove 1 Alcove 2 Alcove 3 and

July 24, 2009 NuFact09 - David Boehnlein 18

proton in Alcove-1, Alcove-2, Alcove-3, and Alcove-4.

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SLIDE 19

Samples for Neutron Studies

AA 06

m

AA-06 AA-07 AA-08 AA-09

100 cm Distance each 10 cm

AA-10 AA-11 AA-12 AA-13

60 cm

AA-13 AA-14 AA-15 AA-16 AA 17

Beam Size: 3 ft di t

AA-17

3 ft. diameter Decay Pipe:

July 24, 2009 NuFact09 - David Boehnlein 19

Decay Pipe: 6 ft. diameter

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SLIDE 20

Activation Yields vs Charge

  • Alcove 1

101

0711NuMI Alcove-1

Na-24

  • Plot of

nuclides

100

lds

natCu

C+ C Na 24

vs change in nuclear

10 1

sobaric yiel

C+ C- △ ▽

charge.

  • Fitted to

10-1

raction of is

tted to Rudstam’ s

10-2

Fr

s empirical formula.

  • 5
  • 4
  • 3
  • 2
  • 1

1 2 3 4 5 10-3

Z-Z

Neutron deficient Neutron rich I □

July 24, 2009 NuFact09 - David Boehnlein 20

Z-Zp

Neutron deficient Neutron rich

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SLIDE 21

Theoretical calculation Theoretical calculation

Target (Graphite) 120 GeV -256kW typical Decay pipe (670m long – 2m diam.) MARS code MARS code Simulate interaction and transport of 120 GeV proton and secondary particles Fermilab rock Ca : O : C : Mg : H = 0 09 : 0 56 : 0 17 : Absorber hall and muon alcoves 0.09 : 0.56 : 0.17 : 0.08 : 0.10 ρ=2.85 g/cm3

July 24, 2009 NuFact09 - David Boehnlein 21 Radiations around intense muon beam (T.Sanami)