1 HiRadMat Proposal HRMT-22: Tungsten Powder Target Experiment (A follow-up to the HRMT-10...

1

HiRadMat Proposal HRMT-22:

Tungsten Powder Target Experiment

(A follow-up to the HRMT-10 ‘W-Thimble’ Experiment in 2012)

Chris Densham, Otto Caretta, Tristan Davenne, Mike Fitton, Peter Loveridge, Joe O’Dell(RAL)

Ilias Efthymiopoulos, Nikolaos Charitonidis(CERN)

2 HiRadMat Technical Review, July 2014

Previous In-Beam Test: HRMT-10, 2012

Beam

LDV/camera

Single tungsten powder sample in an open trough configuration

Helium environment Remote diagnostics via LDV and high-

speed camera Successfully identified a beam intensity

eruption threshold

Open trough Assembly

Tungsten powder response to a 440 GeV proton beam pulse at HiRadMat


HRMT-10: What We Learned

Identified an Energy threshold, beyond which significant eruption of the powder occurs

Lift height correlates with deposited energy Eruption velocities are low when compared to liquid metal splashes

HRMT-10: Open Questions Can Aerodynamic processes alone be shown to account for the observed

response? Or is there something else going on? Can we rule out other mechanisms such as:

i. direct momentum transfer between grains (i.e. shock-transmission through the bulk solid)

ii. An electrostatic mechanismiii. Trough Wall vibrations exciting the powder


Apparatus for the HRMT-22 In-Beam TestTop window to view sample disruption

Lighting re-configured to allow a view of the full

trough length

Outer Vessel

Inner Vessel

High Speed Camera

LDV

Horizontal linear stage to switch

between samplesSample #1

‘Small’ particlesTrough

Sample #2‘Large’

particlesTrough

Sample #3‘Small’

particlesTrough

Sample #4‘Large’

particlesTube


Key Improvements for a the HRMT-22 Experiment

1. Test in both vacuum and helium environmentsIf we see an eruption in vacuum then it cannot be due to an aerodynamic mechanism.

s

2 bar gset

17,400 ccHe @ 1.4 bar a

6,500 ccVacuum

Tunnel air @ 1 bar a 1 bar gset

2. Vessel updatesElongated beam windows to facilitate hitting multiple samples. Extra optical window in the lid permits a view of the disrupted sample from above.

3. New Trough Conceptmultiple samples, stiff (high natural frequency), thermally linked to vessel.


Key Improvements for a the HRMT-22 Experiment

4. Use mono-dispersed spherical tungsten powderTo facilitate better correlation of results with analytical / theoretical pressure drop and drag models.

5. View along the full length of the troughTo allow better correlation of lift vs energy deposition as the shower builds up along the sample

Energy deposited in a tungsten powder samplefrom FLUKA simulation

30 c

m lo

ng s

ampl

e

6. Reconfigure the lighting rigMore intensive lighting to permit a faster camera frame rate


HRMT-22 Outer Containment Vessel


HRMT-22 Inner Containment Vessel


Part Name DRG No. Material Mass (g)Quantity Total Mass (g)

Outer Box Sides TD-1183-882 Al Alloy 6082 11000 1 11000

Inner Box Cover TD-1183-902 Al Alloy 6082 8800 1 8800

Outer Box Base Plate TD-1183-821 Al Alloy 6082 6600 1 6600

Glass Window Soda-lime Glass 1809 2 3618

Light Bracket Post TD-1183-941 Copper OFHC 578 6 3468

Inner Box Base Plate TD-1183-901 Al Alloy 6082 2703 1 2703

Optical Window Retainer Al Alloy 6082 603 2 1206

Pressure relief valves/Pipes St. Steel 1091 1 1091

Tungsten Powder Tungsten 850 1 850

Outer Box Feedthrough Flange TD-1183-931 St. Steel 774 1 774

Powder Trough Saddle TD-1183-905 Titanium Alloy (TiA14V) 300 2 600

M6x16 Screws A2 St. Steel 5.5 96 528

M6x25 Screws A2 St. Steel 7.2 44 316.8

Beam Window Flange TD-1183-804 Al Alloy 6082 66 4 264

Pressure Sensor St. Steel body 120 2 240

Ball valves Brass 217 1 217

Tungsten Powder Holder - Inner TD-1183-903 Pure Titanium 101 1 101

Tungsten Powder Holder - Outer TD-1183-904 Pure Titanium 89 1 89

Beam Window TD-1183-808 Titanium Alloy (TiA14V) 22 4 88

M4x16 Screws A2 St. Steel 2.1 32 67.2

LED cluster 4 12 48

Extra Screws A2 St. Steel 44 1 44

Window Packer Gasket Klingersil 15 2 30

42675

217

3468

30573

3061

688200

850

3618

Mass (g) Content by Material

Brass

Copper OFHC

Al Alloy 6082

A2 St. Steel

Ti Alloy (Ti6Al4V)

Pure Titanium

Tungsten

Glass

43kg total mass


Experiment Outline

Sample #1Small grainsOpen Trough

Vacuum2x1011 ppp

Eruption ?

VacuumSame beam

Vacuum1x1012 ppp

Helium2x1011 ppp

Y

NEruption ?

Y

NEruption ?

Helium2x1011 ppp

Y

N ?

Option ‘A’Higher

Intensity

Option ‘B’Vary the

Beam Posn.

Helium2x1011 ppp

Vary intensity and monitor

container wall with LDV

Sample #2Large grainsOpen Trough

Sample #3Small grainsOpen Trough

Sample #4Large grainsClosed Tube

Start

End


Preliminary Pulse List

HRMT-22 Beam Pulse ListCreated:

DRAFT 04-July-2014

Beam Pulse List

NoIntensity Beam spot [mm] Bunch

spacing [ns]Pulse length

[us]# bunches p/bunch Total Sigma_x Sigma_y1 5.00E+10 2.0 2.0 2 2.00E+11 2.0 2.0 3 2.00E+11 2.0 2.0 4 1.00E+12 2.0 2.0 5 5.00E+10 2.0 2.0 6 2.00E+11 2.0 2.0 7 2.00E+11 2.0 2.0 8 1.00E+12 2.0 2.0 9 5.00E+10 2.0 2.0

10 2.00E+11 2.0 2.0 11 2.00E+11 2.0 2.0 12 1.00E+12 2.0 2.0 13 5.00E+10 2.0 2.0 14 2.00E+11 2.0 2.0 15 2.00E+11 2.0 2.0 16 1.00E+12 2.0 2.0

Total 5.80E+12 Allow for a total budget of up to 1e13 protons (a few extra shots?)


Obs

erve

d Er

uptio

ns

• Observed eruption threshold is well below the melting temperature of tungsten

Temperature Jump in Vessel Components

Note: We do not intend to approach the melting point in the tungsten grains or any other part of the apparatus.

0

20

40

60

80

100

120

0.1

1

10

100

1000

10000

0 1E+12 2E+12 3E+12 4E+12 5E+12 6E+12 7E+12

Ener

gy d

epos

ited

in s

ampl

e ho

lder

[kJ

]

Peak

tem

pera

ture

Jum

p in

var

ious

par

ts o

f sa

mpl

e ho

lder

[K]

Number of protons per pulse

titanium front window

titanium rear window

sil icon dioxide side window

tungsten

aluminium

tungsten melting temperature

energy deposited in sample holder


Activation Studies: FLUKA Model Geometry

Inner Container (Al)container

Inner Container (Al)container

Outer Container (Al)

Outer Container (Al)

Powder Sample (W)

Powder Sample (W)

Beam Window (Ti alloy)

Beam Window (Ti alloy)

BEAM

Irradiation Profile used in the simulations : 1 x 1013 protons in 1 second –

440GeV/c, sigma = 2mm Cooling times : 1 hour, 1 day, 1 week, 1 month, 2 months, 4 months Precision simulations: EMF-ON, residual nuclei decays, etc…


Activation Dose Rates (μSv/h)

1 hour 1 day 1 week

1 month 2 months4 months

Maximum dose rate on the sample: 3.7 Sv/h

Maximum dose rate on the sample: 103 mSv/h

Maximum dose rate on the sample : 9 mSv/h

Maximum dose rate on the sample : 925 μSv/h




Activation Dose Rate Summary

Cooling time

Outer VesselDose Rate [uSv/h] –

Top of container

Inner VesselDose Rate [uSv/h] –

Top of container

Maximum Dose Rate on the Tungsten Sample [uSv/h]

1 hour 2.74 x 104 5.14 x 104 3.70 x 106

1day 1.55 x 103 2.90 x 103 1.03 x 105

1 week 49.0 113 9.0 x 103

1 month 5.0 12 925

2 months 3.0 6 476

4 months 1.79 3.98 241

A cool-down time of several months is foreseen prior to manually handling the container.

We do not plan to remove the powder sample from its container post irradiation.


Radiation Protection Assessment

# Item Description Hazard Precautions

Lik

elyh

oo

d

Sev

erit

y

Ris

k R

atin

g

1 Pre-existing activation of the experimental area

Remnant activation from previous uses of the HiRadMAT tunnel

Radiation dose ● Off-line setup to minimise time spent underground● TNC Installation via a rometely controlled crane● Observe the CERN radiation access controls

1 4 4

Optical Window Rupture

Beam Window Rupture

Sample vessel Rupture

Seal failure

3 Fire / explosion Ignition of metallic powder Damage to aparatus. Potential release of radioactive material

● Minimise the required powder sample volume● Inert gas (Helium) environment inside the sample vessel● Apparatus constructed from non-flammable materials

1 4 4

4 Accidental high intensity pulse

Apparatus not designed to deal with HiRadMat full intensity pulses

Vessel damage, loss of containment?

● Communication with the machine control room during the experiment● Clear documentation - pulse list etc.

2 4 8

5 Sample contamination

e.g. water from the cooling circuit, air from the tunnel, etc

Nasty radiochemical effects, corrosion etc

● Double containment● External water loop

1 4 4

6 Experiment Diagnostics

Perform measurements in a high radiation area

Prompt radiation dose, activation of equipment

● Remote diagnostics only● Observe the CERN radiation access controls

1 4 4

The powder sample must be transported to a storage area to allow for a cool-off periodExtraction of the sample vessel from the outer box

8 PIE Post irradiation observations Potential radiation dose / release of radioactive powder

● Cool-down period after the experiment● Vessel design/material choice to limit activation● Do not plan to extract the sample from its container post irradiation● Post irradiation observations limited to photographs of the disrupted sample taken through the vessel optical windows

1 4 4

Loss of powder containment

Radioactive powder dispersal into the environment. Potential for inhalation of fine radioactive particulate material

8

Set-Up

Running the Experiments

Decomissioning

7

● Double containment● Robust engineering design, pressure test, leak test.● Minimise the required powder sample volume● Minimise the activation level (number of primary protons)● Pressure relief valve● Monitor pressure inside the primary containment

2 4 82

Loss of powder containment during handling operations

Radioactive powder dispersal into the environment. Potential for inhalation of fine radioactive particulates

● Trial the handling operations● Maintain the double containment during transport operations● Design to minimise the volume of contaminated waste material

2 4



Lik

elyh

oo

d

Sev

erit

y

Ris

k R

atin

g

1 Pre-existing activation of the experimental area

Remnant activation from previous uses of the HiRadMAT tunnel

Radiation dose ● Off-line setup to minimise time spent underground● TNC Installation via a rometely controlled crane● Observe the CERN radiation access controls

1 4 4

Optical Window Rupture

Beam Window Rupture

Sample vessel Rupture

Seal failure

3 Fire / explosion Ignition of metallic powder Damage to aparatus. Potential release of radioactive material

● Minimise the required powder sample volume● Inert gas (Helium) environment inside the sample vessel● Apparatus constructed from non-flammable materials

1 4 4

4 Accidental high intensity pulse

Apparatus not designed to deal with HiRadMat full intensity pulses

Vessel damage, loss of containment?

● Communication with the machine control room during the experiment● Clear documentation - pulse list etc.

2 4 8

5 Sample contamination

e.g. water from the cooling circuit, air from the tunnel, etc

Nasty radiochemical effects, corrosion etc

● Double containment● External water loop

1 4 4

6 Experiment Diagnostics

Perform measurements in a high radiation area

Prompt radiation dose, activation of equipment

● Remote diagnostics only● Observe the CERN radiation access controls

1 4 4

The powder sample must be transported to a storage area to allow for a cool-off periodExtraction of the sample vessel from the outer box

8 PIE Post irradiation observations Potential radiation dose / release of radioactive powder

● Cool-down period after the experiment● Vessel design/material choice to limit activation● Do not plan to extract the sample from its container post irradiation● Post irradiation observations limited to photographs of the disrupted sample taken through the vessel optical windows

1 4 4

Loss of powder containment

Radioactive powder dispersal into the environment. Potential for inhalation of fine radioactive particulate material

8

Set-Up

Running the Experiments

Decomissioning

7

● Double containment● Robust engineering design, pressure test, leak test.● Minimise the required powder sample volume● Minimise the activation level (number of primary protons)● Pressure relief valve● Monitor pressure inside the primary containment

2 4 82

Loss of powder containment during handling operations

Radioactive powder dispersal into the environment. Potential for inhalation of fine radioactive particulates

● Trial the handling operations● Maintain the double containment during transport operations● Design to minimise the volume of contaminated waste material

2 4

Radiation Protection Assessment

Precautions for the Experiment:(ALARA principle)

• Offline setup

• Remote instrumentation/ diagnostics

• Double containment of the powder

• Cool-down prior to dismounting the vessel from the experiment table

• Do not plan to remove the sample from its container for post irradiation measurements


Other Safety Considerations


Lik

elyh

oo

d

Sev

erit

y

Ris

k R

atin

g

1 Powder handling Tungsten powder may become airborn during handling / transfer operations

Inhalation of fine particulate material

● Minimise the required powder sample volume● Handle powder in a well ventilated area● PPE - mask, gloves, overcoat● Transport powder in a sealed container

3 1 3

2 Manual Handling Assembly and integration of the two containment vessels

Injury due to lifting heavy object

● Vessel broken down into manageable single components● Carry handles on inner vessel● Use trolley to tansfer aparatus to the tunnel● test stand an be lifted by crane in BA7 and in TNC tunnel

1 1 1

3 Pressure Vessel / window rupture due to applied overpressure / vacuum

Uncontrolled loss of containment, projectiles

● Robust engineering design● Pressure test as part of commissioning● Pressure relief valves

1 3 3

4 Fire Apparatus catches fire Burns, toxic fumes ● Non-flammable materials used in construction● innert gas / vacuum environment inside the vessel● No human access to the tunnel during experiments

1 3 3

5 Lighting rig gets hot

LED lights generate heat when switched on

Burns from contact with hot components

● LED's mounted inside outer vessel● Only switch on when neccessary● Thermocouples monitor the temperature● Heat sink design and water cooling loop

3 1 3

6 Heating of the powder sample by the beam

The powder sample may be progressively heated by multiple beam shots

Melting of the powder grains, damage to the vessel components

● Sample contained inside purpose made vessel● Temperature rise in vessel components has been calculated● Apropriate thermal cooling time between shots● Water cooling loop available

2 2 4

7 Electrical Remotely operated electrical equipment: lighting rig, translation stage, lift table, instrumentation

Electric shock ● Low voltage connections between the control room and the test stand● Testing and commissioning prior to arrival at CERN

1 2 2

8 Misaligned beam/target

Beam strikes some other part of the apparatus

Vessel damaged ● Offline survey / comissioning● Positional feedback to control room

2 3 6

9 Moving parts Unexpected movements. Remotely operated equipment.

finger trap, impact, etc. ● No human access in the tunnel during operation● local E-stop button on the translation stage● Low speed drives

2 2 4



Lik

elyh

oo

d

Sev

erit

y

Ris

k R

atin

g

1 Powder handling Tungsten powder may become airborn during handling / transfer operations

Inhalation of fine particulate material

● Minimise the required powder sample volume● Handle powder in a well ventilated area● PPE - mask, gloves, overcoat● Transport powder in a sealed container

3 1 3

2 Manual Handling Assembly and integration of the two containment vessels

Injury due to lifting heavy object

● Vessel broken down into manageable single components● Carry handles on inner vessel● Use trolley to tansfer aparatus to the tunnel● test stand an be lifted by crane in BA7 and in TNC tunnel

1 1 1

3 Pressure Vessel / window rupture due to applied overpressure / vacuum

Uncontrolled loss of containment, projectiles

● Robust engineering design● Pressure test as part of commissioning● Pressure relief valves

1 3 3

4 Fire Apparatus catches fire Burns, toxic fumes ● Non-flammable materials used in construction● innert gas / vacuum environment inside the vessel● No human access to the tunnel during experiments

1 3 3

5 Lighting rig gets hot

LED lights generate heat when switched on

Burns from contact with hot components

● LED's mounted inside outer vessel● Only switch on when neccessary● Thermocouples monitor the temperature● Heat sink design and water cooling loop

3 1 3

6 Heating of the powder sample by the beam

The powder sample may be progressively heated by multiple beam shots

Melting of the powder grains, damage to the vessel components

● Sample contained inside purpose made vessel● Temperature rise in vessel components has been calculated● Apropriate thermal cooling time between shots● Water cooling loop available

2 2 4

7 Electrical Remotely operated electrical equipment: lighting rig, translation stage, lift table, instrumentation

Electric shock ● Low voltage connections between the control room and the test stand● Testing and commissioning prior to arrival at CERN

1 2 2

8 Misaligned beam/target

Beam strikes some other part of the apparatus

Vessel damaged ● Offline survey / comissioning● Positional feedback to control room

2 3 6

9 Moving parts Unexpected movements. Remotely operated equipment.

finger trap, impact, etc. ● No human access in the tunnel during operation● local E-stop button on the translation stage● Low speed drives

2 2 4

Other Safety Considerations

Precautions for the Experiment:(ALARA principle)

• Hydraulic pressure test

• Helium Leak test

• Non-flammable materials

• Inert gas / vacuum environment

• Low-voltage connections between control room and experiment table

• Off-line trial survey/alignment


CFD Model of Pressure rise in sealed sample holder

As a result of convection between gas and hot powder the gas temperature and pressure in the sample holder can increase

Peak pressure and temperature depend on cooled surface area of container

Inner containment vessel rated for 2 bar internal pressure

0.25 bar


Sample cool down time (time between shots)

0 1 2 3 4 5 6 7 80

10

20

30

40

50

60

time [minutes]

Perc

ent r

educ

tion

of a

vera

ge te

mpe

ratu

re ju

mp

))(/(/

)()()(

311

3132222111

TTmCpUAdtdT

TTUATTAhTTAhQ

T3T1

T2

• Wall temperature (t3) maintained by water-cooled base

• Sample temperature (t1) depends on pulse intensity

• Exponential temperature decay – depends on natural convection between powder and helium and between helium and cooled containment box

• In 7 minutes the temperature has returned to within 1% of its value before the pulse


Summary

In 2012 the HRMT-10 experiment we observed beam-induced eruptions in a tungsten powder target. A new experimental cell has been designed for the follow-up HRMT-22 experiment.

The rig incorporates the successful safety and containment features implemented with the first experiment: Double containment Remote diagnostics Offline setup

The improvements in the design include: The possibility to house multiple independent samples The possibility to test in vacuum and helium environments Wider camera field of view More intense lighting (higher camera frame rate?) Mono-dispersed spherical powder

1 HiRadMat Proposal HRMT-22: Tungsten Powder Target Experiment (A follow-up to the HRMT-10...

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