# US 2017/0285121 A1 · Combined shim and bore cooling assembly

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- Number: US 2017/0285121 A1
- Document ID: US20170285121A1
- Status: Published application
- Kind: A1
- Application number: 15/510,300
- Filed: 2015-09-09
- Published: 2017-10-05
- Earliest claimed: 2014-09-12
- Assignees: Siemens Healthcare GmbH
- Applicants: Siemens Healthcare Limited
- Inventors: Nicholas ALEY; Neil John BELTON; Martin Howard HEMPSTEAD; Marcel KRUIP; Patrick William RETZ
- Web page: https://patentgrep.com/patent/US20170285121A1

## CPC

- G01R 33/3873: using ferromagnetic bodies {; Passive shimming}
- G01R 33/3403: {Means for cooling of the RF coils, e.g. a refrigerator or a cooling vessel specially adapted for housing an RF coil}
- G01R 33/3815: with superconducting coils, e.g. power supply therefor
- G01R 33/38: Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
- G01R 33/3804: {Additional hardware for cooling or heating of the magnet assembly, for housing a cooled or heated part of the magnet assembly or for temperature control of the magnet assembly}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

An arrangement for shimming a background magnetic field of a magnetic resonance imaging apparatus having an outer vacuum chamber (OVC) bore tube (1). Rails (8, 9) are provided on the OVC bore tube and shim trays (4) are mounted between respective rails.

## Claims

### Claim 1

An arrangement for shimming a background magnetic field of a cylindrical superconducting magnet for a magnetic resonance imaging apparatus, having a cylindrical outer vacuum chamber (OVC) bore tube, with rails on the OVC bore tube and shim trays containing shim elements mounted between respective rails, said arrangement comprising:
the rails having grooves that accommodate respective edges of respective shim trays;
an interference fit between a shim tray and at least one of the respective groove;
at least some of the rails having a passageway, said passageways being connected by conduits into a coolant circuit for circulation of a coolant fluid therethrough; and
the rails and the shim tray being at least partially constructed of a thermally conductive material, and being in thermal contact with one another and the OVC bore tube, causing the coolant fluid to stabilize a temperature of the OVC bore tube, the shim tray and the shim elements.

### Claim 2 (depends on 1)

An arrangement according to claim 1 wherein the shim trays are mounted to slide along a length of the rails and wherein the arrangement comprises a fixing arrangement that holds the shim tray in a desired position along the length of the rails.

### Claim 3 (depends on 1)

An arrangement according to claim 1 wherein at least one shim tray comprises a ferromagnetic or paramagnetic material.

### Claim 4 (depends on 1)

An arrangement according to claim 1 wherein each the shim tray comprises a bottom piece and a lid that is secured to the bottom piece.

### Claim 5 (depends on 1)

An arrangement according to claim 1 wherein each shim tray has respective edges each having a lateral lip, with the grooves retaining the shim trays by the lateral lips.

### Claim 6 (depends on 1)

An arrangement according to claim 1 wherein at least one of the rails comprises a ferromagnetic or paramagnetic material.

### Claim 7 (depends on 1)

An arrangement according to claim 1 wherein the coolant circuit comprises a cooler.

### Claim 8 (depends on 1)

An arrangement according to claim 1 wherein the coolant circuit comprises a circulator.

### Claim 9 (depends on 1)

An arrangement according to claim 1 wherein multiple arrangements of shim trays retained by said rails are located adjacent one another around the cylindrical OVC bore tube.

### Claim 10 (depends on 9)

An arrangement according to claim 9 wherein each rail has respective grooves therein, which each hold a respective edge of each of two adjacent shim trays.

### Claim 11 (depends on 9)

An arrangement according to claim 9 wherein each rail has respective grooves therein, which each hold a respective lateral lip of each of two adjacent shim trays.

### Claim 12 (depends on 9)

An arrangement according to claim 9 wherein the shim trays and rails extend around the OVC bore tube, forming a thermal shield for the OVC bore tube.