DEVELOPMENT OF SSR2 FOCUSING LENSES FOR PIP-II … · 2019-09-11 · DEVELOPMENT OF SSR2 FOCUSING...

DEVELOPMENT OF SSR2 FOCUSING LENSES FOR PIP-II (Feasibility Studies for Conduction Cooled Magnet)

Electromagnetic Application Section

Electromagnetic Applications & Instrumentation Division

Team members: Kumud Singh, Janvin Itteera, Mahima, R R Singh , Rajesh Chimurkar, Rajesh Jalan & Sanjay

Malhotra

September 11, 2019 IIFC Magnet meeting presentation - Kumud Singh | SSR2 lenses For PIP-II

Vacuum pumps

Cryostat housing magnet

Electronics rack

Power diode connected in shunt with magnet

• SSR1 cryomodule Layout.

• Suggested magnet configuration inside cryomodule.

• 2D sketch of the magnet assembly.

• Conduction cooling arrangement.

• Boundary Conditions & ∆T for the cooling system for Coils

• Temperature difference in the coil winding

• Boundary Conditions & ∆T for the cooling system for current leads

• Summary

Outline


Vacuum pumps


Electronics rack


SSR1 Cryomodule Layout

SSR cryomodule cross-section –Ref [1]

Inputs from SSR cryomodule layout :

Pipe G – Diameter 6 inch

Location of 2 Phase Helium pipe –

00

Location of current leads for the

magnets – 300

Thermal Shield 50 K


Suggested magnet arrangement inside cryomodule

2 Phase Helium pipe

High temperature portion of current leads (copper)

Low temperature portion of current leads (HTS leads)

Coil former (Copper)

Heat Sink (Aluminium)

Conduction strips (Al foils/Copper Braids)

Inputs required:

HTS Current leads dimensions & Heat

Leak Specifications ( For testing of the

magnets at BARC SUPEROX make

HTS current leads (0.1W/pair) will be

used in test cryostat)

Radial spatial constraints around

periphery of the magnet ?

Arrangement of conduction strips from

2K pipe to coil heat sink and current

leads on one side will need to be

planned carefully.

Beam pipe (SS 316L)

Coil Conduction Plates (Azimuthal locations)



Electronics rack


2D sketch of magnet assembly

Note : Not to scale


Vacuum pumps


Electronics rack


Conduction cooling arrangement – Block diagram

Rad

iati

on

Heat

2 K pipe

Pipe/Current leads

Conduction strips

Low temperature stage for

current leads - Al Heat Sink

Conduction plates anchored to

Aluminium Heat sink

Conduction plates

(coil end)

Conduction plates

(Coil Longitudinal)

Magnet coil

Conduction strips/braids Clamped to

2K pipe

Thermal leak from the

current leads Ac losses

(Transient)

The cooling system is designed to cool the magnet via two thermal conduction passes as follows: (Pass 1): 2K pipe Cooling of SC coil (Pass 2): 2K pipe Cooling of the HTS current leads


Vacuum pumps Electronics rack


Heat Load Calculation

AC Losses

Hysteresis Loss

𝑷𝒉𝒚 = 𝟒

𝟑𝝅 𝑱𝒄 𝒓𝒇

𝒅𝑩

𝒅𝒕𝟏 +

𝑱𝒐𝒑

𝑱𝒄

𝟐

Coupling Loss

𝑷𝒄𝒑 = 2 𝑰𝒑𝟐

𝟖 𝝅𝟐 𝝆𝒆

𝒅𝑩

𝒅𝒕

𝟐

Eddy Current Loss

Radiated heat Losses

Radiated heat from magnet

𝑸𝒓 = 𝜺 𝝈 𝑨

(𝒏+𝟏) ( 𝑻𝑯

𝟐 - 𝑻𝑳𝟐)

Losses Steady State During Ramping

AC losses 0 mW 10 mW

Radiated Heat 3 mW 3 mW

Current lead

(10 leads)

0.5W (0.1W/

Pair)

0.51W

Beam losses ? ?

Heat load on the magnet (Ball park estimates)

Filament diameter-13 μm

Ramp Rate – 20 minutes

Magnet dimensions – 250mm OD x

200 mm length

Thermal shield temperature – 50K

Magnet Temperature – 2K

Emissivity – 0.052




Boundary Conditions & ∆T for the cooling system for Coils

Parameter Value Assumptions

Conduction area (2K pipe/ Al sheet interface) 0.0191 m2 ɸ76.2 mm x 20 mm width x 4

Pipe wall thickness 1.0 mm

Thermal conductivity of the pipe wall 0.1 W/m-K @2K [3]

Resin Adhesive thickness 0.1 mm

Thermal conductivity of the resin 0.03 W/m-K @2K [3]

Conduction Area between pipe and heat sink 160 mm2 2 mm thickness x 40 mm width

Conduction plate length (2000W/m-K) 200 mm Al -5N, RRR 1000

Conduction Area of heat sink (20W/m-K) 4000 mm2 20 mm thick x 100 mm x 2

Heat sink length 200 mm Al 1050, RRR 30

Steady State

(3mW Heat load)

During Ramping

(13 mW heat load)

∆T in pipe wall 1.57 mK 6.8 mK

∆T in resin 0.52 mK 2.25 mK




Boundary Conditions & ∆T for the cooling system for Coils … continued


∆T in conduction plate 1.87 mK 8.1 mK

∆T in heat sink / superconducting coil 7.5 mK 32.5 mK

Conduction area for conduction plate on coil 240 mm2 30 mm x 2 mm width x 4

Conduction length 200 mm

Thermal conductivity of the conduction plate 1000 W/m-K @2K [3] RRR 500

Steady State During Ramping

∆T in conduction plate 2.5 mK 10.83 mK

Total ∆T 13.96 mK 60.48 mK


Vacuum pumps

The equivalent conductivity model

Temperature difference in the Coil winding

The coil cross-section

λ𝑐𝑜𝑖𝑙 = 𝑙𝑤 + 𝑙𝑟

𝑙𝑤λ𝑟

+ 𝑙𝑟λ𝑟

Equivalent thermal conductivity

Sr. No Parameter Value

1. Superconductor diameter 0.5 mm

2. Number of turns 8325+100+1066

3. Coil cross section 52.5mm ID 84.5

mm OD x

150mm long =

4800 mm2

4. Area ratio for

Superconductor

34%

5. Area ratio for Resin 66%

6. Thermal conductivity for

superconductor

0.3 W/m/K

7. Thermal conductivity for

resin

0.03 W/m/K


Vacuum pumps

Temperature difference in the Coil winding … continued

Sr. No Parameter Value

1. Conduction Area 0.054 m 2

2. Conduction Length 35 mm

3. Thermal conductivity 0.046 W/m-K

Steady State (3mW) During Ramping

(13mW)

4. ∆T in Magnet Coil 42 mK 183 mK

Total ∆T in Coil Cooling System 55.96 mK 243.48 mK

Calculated Result for temperature difference in Coil is ~0.25K




HTS current leads

Operating Current A (@ 64K)

Width Full length (mm)

HTS length (mm)

Terminal Connection holes Calculated Heat Leak 64-4.2K (pair), mW

250A 14-16 250-400 180-300 25-50 5-6.5 < 100mW

SUPEROX make HTS current lead specifications taken for calculations




Boundary Conditions & ∆T for the cooling system for current leads


Conduction area (2K pipe/ Al sheet interface) 0.0156 mm2 ɸ76.2 mm x 65 mm width x 1

Pipe wall thickness 1.0 mm

Thermal conductivity of the pipe wall 0.1 W/m-K @2K

Resin Adhesive thickness 0.1 mm

Thermal conductivity of the resin 0.03 W/m-K @2K

Conduction Area between pipe and heat sink 325 mm2 5 mm thickness x 65 mm width

Conduction plate length 300 mm

Steady State (0.5W) During Ramping(0.51W)

∆T in pipe wall 321 mK 327.42 mK

∆T in resin 107 mK 109.14 mK

∆T in conduction plate 230 mK 234.6 mK

Total ∆T 658mK 676.56 mK

Calculated Result for temperature difference in current leads is ~0.7K




Summary & Future Work

• Ball park estimates for heat load and temperature differences for magnet coil and current leads

have been calculated.

• DAE will carry out the detailed thermal analysis of the proposed magnet design.

• Recovery time after Quench of the magnet will be calculated and presented with the magnet

design.

• FNAL shall confirm the spatial constraints & current lead interface for the magnet from

cryomodule perspective.

• PDR and TRS for the magnet shall be targeted to be completed before October end. FDR

completion shall be targeted for Dec -2019 in order to close the conduction cooled magnet R&D in

next year.




References

[1] SSR1 Cryomodule, Vincent Roger, International workshop on cryomodule design and

standardization, 6th September 2018

[2] Performance of Conduction Cooled Splittable Superconducting Magnet Package for Linear

Accelerators , V. Kashikhin , N. Andreev, S. Cheban, J. DiMarco, N. Kimura, A. Makarov, Y.

Orlov, V. Poloubotko, M.Tartaglia, A.Yamamoto

[3] Superconductivity and cryogenics handbook p.1090(Japan)

[4] Feasibility studies for conduction cooled SC quadrupole for ILC cryomoudle

Thank You for your kind attention


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DEVELOPMENT OF SSR2 FOCUSING LENSES FOR PIP-II … · 2019-09-11 · DEVELOPMENT OF SSR2 FOCUSING...

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