Part 2: Cryogenic Performance of SCU0

Part 2: Cryogenic Performance of SCU0

Joel Fuerst

ASD/RF

ASD Seminar

04 March 2013

2

Outline

Introduction

Design heat loads

Operating conditions

Review of cryocooling

Performance

Summary

ASD Seminar: Cryogenic Performance of SCU0 - Part 2 J.D. Fuerst 04MAR2013

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3 3


4 4


Heat load/Operating temperature

Heat

source

Temp

[K]

Design

load

[W]

Installed

capacity

[W]

Magnet 4.3 0.7 3

Rad shield/

beam tube 20 12 40

Rad shield 60 86 224

Main coil

current [A] 500* 600 700

Critical

temp [K] 6.10 5.55 4.95

*design current

Measured Heat Loads, W

4K - stage

(415D 2nd

Stage)

20K – stage

(408S 2nd

Stage)

60K -

stage

(1st

Stages)

I=0A (Beam

chamber: 0W)

0.61 1.46 60.2

I=500A (Beam

chamber: 0W)

0.61 < 12.5 63.2

I=500A (Beam

chamber:

10W)

0.61 < 12.5 80.9

I=500A (Beam

chamber:

20W)

0.61 21.3 87.4

Design Estimation Heat Loads, W

I=500A (Beam

chamber: 10W)

0.685 12.5 86.1

5

SCU Temperatures

5


6

Beam Chamber Temperatures

6


7 7


SCU: Gifford-McMahon (GM) cryocooler cycle

1 2 3 4

Regenerator Performance

8 8


Sumitomo Cryocooler Performance Maps

Cooling power vs. temperature during cooldown

0

5

10

15

20

5.0 10.0 15.0 20.0

Co

olin

g P

ow

er

(W)

2nd Stage Temp (K)

RDK-408S (“20K”)

0

5

10

15

20

0.0 5.0 10.0 15.0

Co

olin

g P

ow

er

(W)

2nd Stage Temp (K)

RDK-415D (“4 K”)

9

First Cooldown (bldg 314)

9


0

50

100

150

200

250

300

6/29/12 12:00 PM 6/30/12 12:00 PM 7/1/12 12:00 PM 7/2/12 12:00 PM

Tem

pera

ture

[K

]

4K Cryocooler US cold head

4K Cryocooler DS cold head

4K Cryocooler DS 1st stage

4K Cryocooler US 1st stage

upper magnet core

10

Second Cooldown (bldg 314)

10


0

50

100

150

200

250

300

8/27/12 3:00 PM 8/28/12 3:00 PM 8/29/12 3:00 PM 8/30/12 3:00 PM

Tem

pera

ture

[K

]



4K Cryocooler DS first stage

4K Cryocooler US first stage

upper magnet core

11

First Cooldown (SR)

11


4K cryocooler US cold head [K] 4K cryocooler DS cold head [K] 4K cryocooler DS 1st stage [K] 4K cryocooler US 1st stage [K]

12

First Warmup (bldg 314)

12


0

50

100

150

200

250

300

350

8/21/12 8:00 AM 8/22/12 8:00 AM 8/23/12 8:00 AM 8/24/12 8:00 AM 8/25/12 8:00 AM

Tem

pera

ture

[K

]





upper magnet core

13

Second Warmup (bldg 314)

13


0

50

100

150

200

250

300

350

8/30/12 12:00 PM 8/31/12 12:00 PM 9/1/12 12:00 PM 9/2/12 12:00 PM 9/3/12 12:00 PM

Tem

pera

ture

[K

]





upper magnet core

14

Steady State – Cryocooler Operation (1)

14


Magnet temp [K]

DS cryocooler coldhead temp [K]

US cryocooler coldhead temp [K]

15

Cryocooler Operation (2)

15


3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

1:06:14 PM 1:06:32 PM 1:06:49 PM 1:07:06 PM 1:07:24 PM 1:07:41 PM

DST 2nd Stage (K)

UST 2nd Stage (K)

16

Changes in magnet current affect coil temperature

16


DS cryocooler coldhead temp [K]

Magnet temp [K]

Main coil current [A]

17

Loss of SR beam current affects magnet temperature

17


Magnet temp [K]


SR current [mA]

18

Beam and magnet currents impact cold mass temps

18


Magnet temp [K] Main coil current [A]

Support frame temp [K] SR current [mA]

19

Long-term Operation

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Helium bath pressure [torr]

SR current [mA]

20

LHe Tank Pressure Regulation

20


LHe Tank Bottom Temp [K]

LHe Tank Pressure [torr]

SR current [mA]

21

Beam-induced Quench

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Magnet temp [K] Main coil current [A]

SR current [mA] Helium pressure [torr]

22

Helium Liquefaction (bldg 314)

22


17.4

17.6

17.8

18

18.2

18.4

18.6

18.8

19

19.2

19.4

8/7/12 12:00 PM 8/7/12 6:00 PM 8/8/12 12:00 AM 8/8/12 6:00 AM 8/8/12 12:00 PM

Liq

uid

Level [c

m]

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Cryocooler shutdown tests (bldg 314)

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750

760

770

780

790

800

810

820

8/16/12 8:00 AM 8/16/12 8:30 AM 8/16/12 9:00 AM 8/16/12 9:30 AM 8/16/12 10:00 AM

LH

e P

ressu

re [To

rr]

DS 415D Shutdown Test - LL at 19.6cm 16AUG2012

750

760

770

780

790

800

810

820

8/15/12 10:15 AM 8/15/12 10:45 AM 8/15/12 11:15 AM 8/15/12 11:45 AM 8/15/12 12:15 PM

LH

e P

ressu

re [To

rr]

US 415D Shutdown Test - LL at 19.6cm 15AUG2012

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Room to Improve

• Add visible cold mass fiducials for external alignment check while cold

• Consider abandoning the recondenser bulb in favor of direct attachment

to the LHe reservoir exterior for both 4 K coolers to improve 4 K capacity

• Explore optimization of refrigeration levels – consider abandoning “20 K”

thermal shield to save cost and improve overall capacity

• Consider reducing LHe reservoir volume (but maintain interior surface

area for efficient recondensation…) to reduce cryostat size

• Optimize current lead design to reduce heat load

• Improve subsystem designs to enable highest possible magnet current

(since this seems to be what users want)

• 1+ meter magnets

• Cryogen-free (“dry”) magnets?


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Part 2: Cryogenic Performance of SCU0

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