Liquid helium cryostat for SQUID-based MRI receivers

Hugh Seton; James McDonald Strachan Hutchison; D. M. Bussell

doi:10.1016/j.cryogenics.2004.11.011

Liquid helium cryostat for SQUID-based MRI receivers

Hugh Seton, James McDonald Strachan Hutchison, D. M. Bussell

Research output: Contribution to journal › Article › peer-review

27 Citations (Scopus)

Abstract

We describe a liquid helium cryostat, developed to cool SQUID-based receivers in low field MRI systems. The cryostat has a 4 L liquid helium capacity, a hold time of over 3 days and accommodates 10 cm diameter receiver coils. New vacuum insulation methods reduce the noise level by at least an order of magnitude compared to existing commercial designs. The minimum detectable field at 425 kHz, with a 5 cm diameter circular coil, was estimated to be 0.018 fT/Hz (1/2) from Q-factor measurements and 0.035 fT/Hz (1/2) by direct measurement with a SQUID amplifier. Further measurements indicated that most of this field noise probably originates with dielectric losses in the cryostat's fibreglass shells. (c) 2005 Elsevier Ltd. All rights reserved.

Original language	English
Pages (from-to)	348-355
Number of pages	7
Journal	Cryogenics
Volume	45
Issue number	5
DOIs	https://doi.org/10.1016/j.cryogenics.2004.11.011
Publication status	Published - May 2005

Keywords

ceramics
liquid helium
SQUIDs
cryostats
QUANTUM INTERFERENCE DEVICE
MAGNETIC-RESONANCE
SYSTEM
NOISE

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10.1016/j.cryogenics.2004.11.011

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title = "Liquid helium cryostat for SQUID-based MRI receivers",

abstract = "We describe a liquid helium cryostat, developed to cool SQUID-based receivers in low field MRI systems. The cryostat has a 4 L liquid helium capacity, a hold time of over 3 days and accommodates 10 cm diameter receiver coils. New vacuum insulation methods reduce the noise level by at least an order of magnitude compared to existing commercial designs. The minimum detectable field at 425 kHz, with a 5 cm diameter circular coil, was estimated to be 0.018 fT/Hz (1/2) from Q-factor measurements and 0.035 fT/Hz (1/2) by direct measurement with a SQUID amplifier. Further measurements indicated that most of this field noise probably originates with dielectric losses in the cryostat's fibreglass shells. (c) 2005 Elsevier Ltd. All rights reserved.",

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TY - JOUR

T1 - Liquid helium cryostat for SQUID-based MRI receivers

AU - Seton, Hugh

AU - Hutchison, James McDonald Strachan

AU - Bussell, D. M.

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N2 - We describe a liquid helium cryostat, developed to cool SQUID-based receivers in low field MRI systems. The cryostat has a 4 L liquid helium capacity, a hold time of over 3 days and accommodates 10 cm diameter receiver coils. New vacuum insulation methods reduce the noise level by at least an order of magnitude compared to existing commercial designs. The minimum detectable field at 425 kHz, with a 5 cm diameter circular coil, was estimated to be 0.018 fT/Hz (1/2) from Q-factor measurements and 0.035 fT/Hz (1/2) by direct measurement with a SQUID amplifier. Further measurements indicated that most of this field noise probably originates with dielectric losses in the cryostat's fibreglass shells. (c) 2005 Elsevier Ltd. All rights reserved.

AB - We describe a liquid helium cryostat, developed to cool SQUID-based receivers in low field MRI systems. The cryostat has a 4 L liquid helium capacity, a hold time of over 3 days and accommodates 10 cm diameter receiver coils. New vacuum insulation methods reduce the noise level by at least an order of magnitude compared to existing commercial designs. The minimum detectable field at 425 kHz, with a 5 cm diameter circular coil, was estimated to be 0.018 fT/Hz (1/2) from Q-factor measurements and 0.035 fT/Hz (1/2) by direct measurement with a SQUID amplifier. Further measurements indicated that most of this field noise probably originates with dielectric losses in the cryostat's fibreglass shells. (c) 2005 Elsevier Ltd. All rights reserved.

KW - ceramics

KW - liquid helium

KW - SQUIDs

KW - cryostats

KW - QUANTUM INTERFERENCE DEVICE

KW - MAGNETIC-RESONANCE

KW - SYSTEM

KW - NOISE

U2 - 10.1016/j.cryogenics.2004.11.011

DO - 10.1016/j.cryogenics.2004.11.011

M3 - Article

VL - 45

SP - 348

EP - 355

JO - Cryogenics

JF - Cryogenics

SN - 0011-2275

IS - 5

ER -

Liquid helium cryostat for SQUID-based MRI receivers

Abstract

Keywords

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