Copyright © 2013 SCKCEN Pb-Bi target for ISOL@MYRRHA: Optimization toward higher yields SCKCEN Mentor : Dr. Lucia-Ana Popescu University Promoter : Prof

Copyright © 2013 SCK•CEN

Pb-Bi target for ISOL@MYRRHA:

Optimization toward higher yields

SCK•CEN Mentor :

Dr. Lucia-Ana PopescuUniversity Promoter :

Prof. Jan Vierendeels

Donald HOUNGBOSCK•CEN, UGENT

[email protected]


IV

III

II

I Context, Previously presented

Yield Optimization Calculations

Outline

LIEBE project: Status

2

Thermo-mechanical loads: Estimation


ContextISOL@MYRRHA --> High power (60 – 120

kW)

3

Pb-Bi target investigated within LIEBE

Proposed in EURISOL DS

Previously presented at BriXOptimization of Hydrodynamics => Fast, Complete and Uniform

evacuation of irradiated Pb-Bi for these concepts


IV

III

II



Outline


4



Yield Optimization

𝜀𝑟𝑒𝑙𝑒𝑎𝑠𝑒

Optimize

5

=

…

𝜀𝑒𝑣𝑎𝑐𝑢𝑎𝑡𝑖𝑜𝑛

𝜀𝑒𝑓𝑓𝑢𝑠𝑖𝑜𝑛Release volume

𝜀𝑑𝑖𝑓𝑓𝑢𝑠𝑖𝑜𝑛


Yield Optimization : Model

6

Evacuation

Diffusion

Effusion

6𝐶𝑟 2

∑𝑛=1

∞

𝑒− 𝑛

2 𝜋2𝐶𝑟 2

(𝑡𝐷𝑆−𝑡𝐸 )

{ 1𝑇 𝑓𝑢𝑙𝑙

,𝑡𝐶<𝑡𝐸<𝑇 𝑓𝑢𝑙𝑙

¿0 , 𝑡𝐸>𝑇 𝑓𝑢𝑙𝑙

∅ 𝑠 (𝑡𝐷𝑆 )

∅ 𝑖 (𝑡 𝐼𝑆 )

𝑡𝐷𝑆

𝑡 𝐼𝑆

𝑡𝐸

0

{ 𝛼 (1−𝑒−ν (𝑡 𝐼𝑆−𝑡𝐷𝑆 ) ) ,𝑡𝐷𝑆≤ 𝑡 𝐼𝑆≤ 𝑡𝐷𝑆+𝑇 𝑑𝑒𝑠

¿𝛼 (𝑒ν (𝑡 𝐼𝑆− 𝑡𝐷𝑆−𝑇 𝑑𝑒𝑠 )−𝑒−ν (𝑡 𝐼𝑆−𝑡𝐷𝑆 ) ) ,𝑡𝐷𝑆+𝑇 𝑑𝑒𝑠<𝑡 𝐼𝑆

Comprehensive Analytical Release Model


Evacuation & Diffusion of Hg

Time [s]

Ra

tio o

f e

vacu

ate

d t

o p

rod

uce

d 17

7 Hg

pe

r u

nit

time

[s-1

]

{ 1𝑇 𝑓𝑢𝑙𝑙

,𝑡𝐶<𝑡𝐸<𝑇 𝑓𝑢𝑙𝑙

¿0 , 𝑡𝐸>𝑇 𝑓𝑢𝑙𝑙

Time [s]

Diff

use

d H

g is

oto

pe

s a

s a

ra

tio o

f in

itia

l Hg

co

nte

nt

pe

r u

nit

time

[s-1

]

6𝐶𝑟 2

∑𝑛=1

∞

𝑒− 𝑛

2 𝜋2𝐶𝑟 2

(𝑡𝐷𝑆−𝑡𝐸 )

Evacuation Diffusion


Yield Optimization: Evacuation & Diffusion of Hg

8

Time [s]

Eva

cuat

ion

& D

iffus

ion

Pro

babi

lity

Den

sity

Fun

ctio

n [F

ract

ion

/ s]

177Hg (T1/2= 118 ms) 19 % efficiency for 12 cm height


Yield Optimization: Effusion of Hg

¿MPP = 17178.4 cm D30 000 collisionsMFP = 0.624138 cm

Percentage of desorbed isotopes arriving at transfer tube per bins of 1-ms

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-0.05%

0.00%

0.05%

0.10%

0.15%

0.20%

0.25%

0.30%

0.35%

0.40%

0.45%

f(x) = 0.00392631080234115 exp( − 3.9235400892594 x )R² = 0.98569837202948

Time (s)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10.00%

0.05%

0.10%

0.15%

0.20%

0.25%

0.30%

0.35%

Time (s)

Release Volume

Feeder volume

Assuming all isotopes desorb at the same time

Desorption actually spread over time (assuming 100 ms)

9


Yield Optimization: Release efficiency

Ove

rall

de

lay

time

dis

trib

utio

n [

Fra

ctio

n /

s]

Ove

rall

Fra

ctio

nal R

elea

se

10

Time [s] Time [s]

∫0

𝑡 𝐼𝑆

∅𝑖 ( 𝑡 𝐼𝑆)exp (−λ∗𝑡 𝐼𝑆 )𝑑𝑡

Accounting for decay

Evacuation and Diffusion

Effusion

0.10.25


Yield Optimization: Diff. chamb. length, 177Hg

0 5 10 15 20 25 30 35 40-1%

0%

1%

2%

3%

4%

5%

6%

Release efficiency 177Hg

Diffusion Chamber Length (cm)

11

Diffusion Chamber Length (cm) 5 10 15 20 25 30 35

Release efficiency (177Hg)

5.78%

3.55%

2.58%

2.02%

1.65%

1.42%

1.19%

Average overall delay time (s)

0.39

0.65

0.89

1.12

1.40

1.54

1.84

Release Volume

Feeder volumeIrradiation volume

20 cm2 cm

12 c

m

1.4 GeV,

1013 prot.


Yield Optimization: Distrib. of Hg isotopes

0 2 4 6 8 10 12 14 16 18 200%

2%

4%

6%

8%

10%

FLUKA179Hg MCNP 179Hg

Irradiation Chamber Length [cm]

0 2 4 6 8 10 12 14 16 18 200%

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

FLUKA 180Hg MCNP 180Hg

Irradiation Chamber Length [cm]0 2 4 6 8 10 12 14 16 18 20

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

FLUKA 181Hg MCNP 181Hg


0.5 2.5 4.5 6.5 8.510.5

12.514.5

16.518.5

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

MCNP 178HgMCNP 179HgMCNP 180HgMCNP 181HgMCNP 191HgMCNP 192HgMCNP 193HgMCNP 194Hg


12

Hg isotopes created along the beam line as a percentage of the total production


5 10 15 208.0E+04

1.3E+05

1.8E+05

2.3E+05

2.8E+05

3.3E+05

3.8E+05

Yield Optimization: Target length, 178Hg

0 2 4 6 8 10 12 14 16 18 200.0E+00

5.0E+04

1.0E+05

1.5E+05

2.0E+05

2.5E+05

3.0E+05

3.5E+05

4.0E+05


178Hg production in the Irrad. vol.

5 10 15 200%

2%

4%

6%

8%

10%

12%

14%

13

Release efficiency: 178Hg

Diffusion Chamber Length [cm] Diffusion Chamber Length [cm]

178Hg yields at transfer line

preliminary

results!preliminary

results!


Yield Optimization: Target length, 177Hg

2 cm

12 c

m

20 cm

Release Volume

1.4 GeV,

1013 prot.

Feeder volume

Irradiation volume

0 2 4 6 8 10 12 14 16 18 200.0E+00

5.0E+04

1.0E+05

1.5E+05

2.0E+05

2.5E+05

3.0E+05

3.5E+05

4.0E+05


178Hg production in the Irrad. vol.

14

4 6 8 10 12 14 16 18 200%

1%

2%

3%

4%

5%

6%

7%Release efficiency: 177Hg

Diffusion Chamber Length [cm]

preliminary

results!

4 6 8 10 12 14 16 18 208.0E+04

9.0E+04

1.0E+05

1.1E+05

1.2E+05

[a.u

.]

Diffusion Chamber Length [cm]

177Hg yields at transfer line, assuming similar production as for 178Hg

preliminary

results!


Yield Optimization: Diff. Chamb. Height

15

0 5 10 15 20 25 300.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

16.00%

18.00%

Release eff (177Hg) Release eff (178Hg) Release eff (179Hg)

Diffusion Chamber Height (cm)

2 cm

12 c

m

20 cm

Release Volume



Yield Optimization: Droplet Radii

16

2 cm

12 c

m

20 cm

Release Volume


Ove

rall

de

lay

time

dis

trib

utio

n [

a.u

.]

Ove

rall

de

lay

time

dis

trib

utio

n [

a.u

.]O

vera

ll d

ela

y tim

e d

istr

ibu

tion

[a

.u.]

Time [s] Time [s]

Time [s]

100 μm radii 3.67% Release efficiency

1.22 s Average overall delay time






Summary & OutlookSummary

Comprehensive release model, Model is analytical but supported by detailed Monte CarloOptimum target length is isotope dependent and ≤ 20 cm for

short lived Hg Optimum diffusion chamber height is isotope dependent and

≤ 5 cm for short lived HgOptimum droplets radii is below 100 μm

OutlookEffusion calculations still to account for:

Presence of a jet at aperture tipDistribution of in-target production Non-uniform vertical droplets distribution due to gravityNon-uniform distribution of droplets concentration in Hg due to

diffusion

2 cm

12 c

m

20 cm

Release Volume



IV

III

II



Outline


18




200 ns (1st bunch)

≤ 2.45 108 Pa ≤ 3.5 108 Pa ≤ 3.6 108 Pa

≤ 1.1 108 Pa

16.4 μs (2nd bunch)

≤ 1.3 108 Pa

32.6 μs (3rd bunch)

Time

Peak pressure inside liquid Pb-Bi

≤ 8.5 107 Pa

Heat Deposition GeV/cm3.p

200ns proton bunches

16μs bunch spacing

2.4 1013 protons

Time

Intensity

200 ns

16.4 μs 32.6 μs


IV

III

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Outline


20




LIEBE project subject to review by Panel of experts in June 2014 Recommendations from the panel of experts received and

integrated Calculation of structural stresses & deformations due to pressure

waves Offline prototype foreseen for this summer Online tests 2016

Grids tested, Shower obtained for spacing up to 0.5mm

Apertures diameter of 0.1 mm.

Designed at CERN and manufactured


Thank you for your attention

Questions


Copyright © 2013 - SCKCEN

PLEASE NOTE!This presentation contains data, information and formats for dedicated use ONLY and may not be

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Documents

Copyright © 2013 SCKCEN Pb-Bi target for ISOL@MYRRHA: Optimization toward higher yields SCKCEN Mentor : Dr. Lucia-Ana Popescu University Promoter : Prof