agilent discovery 205/120 hd gradient coil...6 discovery 205/120 hd gradient coil user guide 1...

Agilent Technologies

Agilent Discovery 205/120 HD Gradient Coil

User Guide

Notices© Agilent Technologies, Inc. 2015

No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or transla-tion into a foreign language) without prior agreement and written consent from Agilent Technologies, Inc. as governed by United States and international copyright laws.

Manual Part Number

9100379800

Edition

Rev B October 2015

Agilent Technologies, Inc.5301 Stevens Creek Boulevard Santa Clara, CA 95051 USA

Warranty

The material contained in this docu-ment is provided “as is,” and is sub-ject to being changed, without notice, in future editions. Further, to the max-imum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied, with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a par-ticular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or perfor-mance of this document or of any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the sep-arate agreement shall control.

Technology Licenses

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.

Restricted Rights Legend

If software is for use in the performance of a U.S. Government prime contract or sub-contract, Software is delivered and licensed as “Commercial computer soft-ware” as defined in DFAR 252.227-7014 (June 1995), or as a “commercial item” as defined in FAR 2.101(a) or as “Restricted computer software” as defined in FAR 52.227-19 (June 1987) or any equivalent agency regulation or contract clause. Use, duplication or disclosure of Software is subject to Agilent Technologies’ standard commercial license terms, and non-DOD Departments and Agencies of the U.S. Government will receive no greater than Restricted Rights as defined in FAR 52.227-19(c)(1-2) (June 1987). U.S. Govern-ment users will receive no greater than Limited Rights as defined in FAR 52.227-14

(June 1987) or DFAR 252.227-7015 (b)(2) (November 1995), as applicable in any technical data.

Safety Notices

CAUTION

A CAUTION notice denotes a hazard. It calls attention to an oper-ating procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.

WARNING

A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly per-formed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated condi-tions are fully understood and met.

Revision Log

Rev A, Mar. 20132

Initial release

Rev B, Oct. 2015

updates for grounding safety.

Discovery 205/120 HD Gradient Coil User Guide 1

Contents

1 Introduction

General Description 4

Safety 5

Warning Symbols 6

2 Specifications

External Characteristics 8

Electromagnetic Characteristics 9

Room Temperature Shim System 10

3 Installation

Preinstallation 12

Mechanical Installation 13

Electrical Installation 15

Gradient coils 15Room temperature shim (RT shim) coils 15Temperature sensors 16Gradient identity (Gradient ID) 18

Cooling Water Installation 19

2 Discovery 205/120 HD Gradient Coil User Guide

3

Agilent Discovery 205/120 HD Gradient CoilUser Guide


1Introduction

General Description 4

Safety 5

Warning Symbols 6


1 Introduction

General Description

The Agilent HD family of gradient coils are fully self- shielded three- axis gradient coils for use in Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS).

The assembly consists of an inner (primary) coil set and an outer (shield) coil set, with appropriate electrical interconnections between the two. The axial (Z) gradient coil is wound from heavy gauge copper strip and the transverse gradient coils (X and Y) are made from sheet copper. The coils are computer optimized and manufactured using CNC machining technology to achieve low resistances and accurate current distributions.

The coils are laid up on glass- reinforced plastic (GRP) formers, interleaved with hollow water- cooling channels, then vacuum- impregnated in epoxy resin. The resulting structure is exceedingly robust and heavy, thus minimizing coil movement during operation.

The HD range of gradients are specially designed for high duty cycle experiments and superior magnetic shielding.

Introduction 1


Safety

Read this manual before attempting to install or remove the gradient coil. Failure to do so can result in personal injury or serious damage to the gradient or magnet system.

WARNING Dangerous voltages are present at power terminals. Always turn off the power supply before connecting or disconnecting the gradient and shim power leads.Allow 30s for the gradient amplifier capacitor bank to discharge before disconnecting cables. Disconnect the X, Y, and Z cables after the shim, ID, and thermometry cables so that the protective earth via the X, Y, and Z cables screen to the RF room/amplifier is disconnected last. Reconnect the X, Y, and Z cables first. Follow the instructions in the Agi-lent MRI systems manual: Switching Gradient Coils on Agilent MRI Sys-tems. After switching off the gradient power amplifier, allow enough time for the capacitor bank to discharge (60s) before disconnecting the gradient cables.

WARNING Protection against dangerous voltages in an insulation fault condition or coolant leak fault.To provide protection, the earth/grounding screen of the gradient cables must be connected to the gradient power supply enclosure earth and fil-ter panel earth if there is an RFI screened room. To provide protection, the coolant must be demineralized water with bio-cide (Accepta 2886) and inhibitor (Accepta 2309) with resistivity ≥1MΩcm. Follow the instructions in the Agilent MRI systems manual: Gradient Cooling System - Flushing Procedure.For gradient coil models with service end metal enclosures. the enclo-sure must be screwed securely onto the end of the magnet cryostat.

WARNING Gradient coil is heavy. Always refer to installation instructions before attempting to load or remove the gradient coil.

CAUTION Never operate the gradient coil without the minimum specified flow of cooling water.


1 Introduction

Warning Symbols

The following symbol is used on warning labels attached to the instrument. When you see this symbol, refer to the relevant operation or service manual for the correct procedure referred to by that warning label.

Figure 1 Warning symbol

CAUTION Never operate the gradient without an appropriate temperature monitoring interlock.

7



2Specifications

External Characteristics 8

Electromagnetic Characteristics 9

Room Temperature Shim System 10


2 Specifications

External Characteristics

Table 1

Description Specification

Outside diameter 205 ± 3 mm

Inside diameter 120 ± 0.5 mm

Overall length excluding connectors To suit magnet

Service end face to magnetic center To suit magnet

Mounting

Service end Aluminum flange bolted to magnet

Patient end Delrin o-ring compression clamp

Adjustment None

Loading From service end

Weight Approx. 65kg

Specifications 2


Electromagnetic Characteristics

Table 2

Characteristic Specification

Strength

X-axis 2.00 mT/m/A ± 5%

Y-axis 2.00 mT/m/A ± 5%

Z-axis 2.00 mT/m/A ± 5%

Gradient linearity over 80mm DSV

X-axis ≤ 5%

Y-axis ≤ 5%

Z-axis ≤ 5%

Orthogonality

X-to-Y 90 ± 1 °

Inductance @ 1 kHz

X-axis 155 µH ± 15%

Y-axis 120 µH ± 15%

Z-axis 140 µH ± 15%

DC resistance @ 20 °C

X-axis 140 ± 25 mΩ

Y-axis 100 ± 25 mΩ

Z-axis 150 ± 25 mΩ

Peak voltage 500 V

Peak current 300 A

RMS current

all axes simultaneously 70A

Active shielding > 99%

NOTE Gradient linearity is the maximum deviation of the field from terms other than the desired linear term. It is expressed as a percentage of the linear term on the surface of the diameter spherical volume (DSV).


2 Specifications

Room Temperature Shim System

Table 3 Room temperature shim system

Shim coil Inductance (mH) Resistance (Ω) Strength (mG/cmn/A)

Z0 0.05 0.30 530.0

Z2 2.22 1.25 87.0

ZX 1.55 1.65 41.0

ZY 1.55 1.65 41.0

XY 0.80 1.65 12.7

X2-Y2 0.80 1.65 12.7

NOTE All specifications are for the gradient coil only and do not include the resistance or inductance of cables or any filters used.

NOTE Shim strengths are defined as the constants Cnm in Romeo, F. and Hoult, D.I., Magnetic Resonance in Medicine, 1, 44-65 (1984).

11



3Installation

Preinstallation 12

Mechanical Installation 13

Electrical Installation 15

Cooling Water Installation 20


3 Installation

Preinstallation

CAUTION Be careful to avoid injury during initial installation and when later inserting and withdrawing the gradient coil from the magnet. The requirements of UK Health & Safety regulations apply:

Lifting Operation and Lifting equipment Regulations (LOLER) 1998

Manual Handling Operation Regulations 1992

WARNING It is possible, although unlikely, that a magnet quench could occur when the gradient is inserted or withdrawn from an energized magnet. If this happens, the collapsing magnetic field can generate eddy currents within the conducting structures of the gradient coil. These currents can cause the gradient to be pulled rapidly into the magnet. When inserting or withdrawing from an energized magnet, take great care not to posi-tion a hand or other body part between the magnet and gradient assem-bly.

CAUTION Do not leave the gradient in the magnet bore when the system is softened and warmed up, as the gradient can be damaged.

CAUTION Use only nonmagnetic tools to install the gradient into the magnet when the magnet is energized.

Installation 3


Mechanical Installation

1 Refer to the customer interface drawing for more information before starting the installation.

2 Loosen (or remove) the patient end o- ring clamp plates. Usually, the patient end of the gradient is loaded into the service end of the magnet.

3 If provided, loosen the three radial clamps at the patient end using a long hex key.

4 Raise the gradient until level with the magnet bore using either a nonmagnetic beam/jack, or at least 5 strong people.

5 Adjust the gradient so that it is parallel with the magnet bore.

6 Carefully ease the gradient into the magnet. A cardboard or Mylar sheet under the gradient may make it easier to slide along the bore. Take extra care if passive shim pieces are affixed to the outer surface of the gradient coil, as these could easily be torn off during loading.

7 Once fully inserted, tighten (or re- attach) the o- ring clamp to the patient end of the gradient (refer to customer interface drawing for screw details). Use the nonmagnetic hex key provided. Do not fully tighten at this stage.

8 Rotate the gradient until it is aligned with 0⁰ (top dead center) on the magnet. The gradient is designed to interface in only one orientation.

9 Fasten the service end plate to the magnet (refer to customer interface drawing for screw details). Use the nonmagnetic hex key provided.

10 If the gradient has axial adjustment screws, these may be loosened to allow the axial position to be altered. Once the isocenter coincides with that of the magnet, retighten the screws.

11 If provided, tighten the three patient end radial clamps to center the gradient radially.

12 Tighten the screws in the patient end o- ring clamp. Start with the screws at the bottom and ensure that the gradient sits radially central to the magnet bore.


3 Installation

Figure 2 Agilent Discovery 205/120 HD overview

patient end o-ring clamp

patient end clamp feet

service end plate

electrical connectors

water connectors

guide ring for hex key

Installation 3


Electrical Installation

Gradient coils

There are three gradient connectors labeled “X AXIS”, “Y AXIS” and “Z AXIS”. These connectors are most commonly panel- mounted on the service end flange of the coil. On some systems (such as Discovery), these connectors are cable- mounted on the end of fly- leads. Refer to the customer interface drawing for more details.

The earth/grounding screen of the gradient cables must be connected to the gradient power supply enclosure earth via the amplifier/filter enclosure cable clamp. The gradient amplifier must have a protective earth connected. If your

WARNING Dangerous voltages are present at power terminals. Always turn off the power supply before connecting or disconnecting the gradient and shim power leads.Allow 30s for the gradient amplifier capacitor bank to discharge before disconnecting cables. Disconnect the X, Y, and Z cables after the shim, ID, and thermometry cables so that the protective earth via the X, Y, and Z cables screen to the RF room/amplifier is disconnected last. Reconnect the X, Y, and Z cables first. Follow the instructions in the Agi-lent MRI systems manual: Switching Gradient Coils on Agilent MRI Sys-tems. After switching off the gradient power amplifier, allow enough time for the capacitor bank to discharge (60s) before disconnecting the gradient cables.

WARNING Protection against dangerous voltages in an insulation fault condition or coolant leak fault.To provide protection, the earth/grounding screen of the gradient cables must be connected to the gradient power supply enclosure earth and fil-ter panel earth if there is an RFI screened room. To provide protection, the coolant must be demineralized water with bio-cide (Accepta 2886) and inhibitor (Accepta 2309) with resistivity ≥1MΩcm. Follow the instructions in the Agilent MRI systems manual: Gradient Cooling System - Flushing Procedure.For gradient coil models with service end metal enclosures. the enclo-sure must be screwed securely onto the end of the magnet cryostat.


3 Installation

system has a RF screened room, make sure that the gradient cable earth/grounding screen is also connected to earth via the RF panel/filter enclosure.

The earth connection from the gradient amplifier to the RF screened room/RF screening cover to the gradient coil via the gradient cables must be electrically tested upon installation and tested routinely as part of your system/facility preventative maintenance schedule.

Choose circuit breakers or fuses with slow time constants, appropriately rated for the RMS current of the coil.

Table 4 shows the pin assignments for each gradient coil. Pins are doubled up to increase current capacity of the connector.

Always turn off the power supply before connecting or disconnecting the gradient and shim power leads. Allow 30 seconds for the gradient amplifier capacitor bank to discharge before disconnecting any cables. Disconnect the shim, ID, and thermometry cables BEFORE disconnecting the X, Y, and Z cables so that the protective earth via the X, Y, and Z cables screen to the RF room/amplifier is disconnected last. Reconnect the X, Y, and Z cables first. Follow the instructions in the manual Switching Gradient Coils on Agilent MRI Systems.

CAUTION In order to avoid damage caused by amplifier overload or latching, use fuses or circuit breakers to protect the gradients.

Table 4 Gradient pin assignments

Polarity Pins

+ve 1 & 2

-ve 3 & 4

Installation 3


Room temperature shim (RT shim) coils

The gradient contains a set of 2nd order RT shims for field correction and a shielded B0 shim for eddy current compensation. Connection to these shims is through the single RT shim connector. Usually this shim connector is panel- mounted on the service end flange, but on some systems it is cable- mounted onto the end of a fly- lead.

Pin assignments are shown in Table 5, along with pin assignments of the Agilent standard Discovery RT shim cable (part number C0751).

The peak current for each shim coil is ±10A; the peak voltage is ±100V.

Gradient coil

Filter box on filter panel for gradient

cables

Shim FilterShim cable earth

X

Z

Y

Filter Panel

T/C

Gradient amp;lifierFilter box

X

Y

Z

RF Console

Thermo Couple cable

Shim cable no earth connection

Via Power Socket

Via Power Socket

Coil ID filter Coil ID cableCoil ID cable

Swaglock fittingsPlastic water pipes

Water ChillerPlastic water Pipe

Via Power Socket


3 Installation

Temperature sensors

The gradient has 6 negative temperature coefficient (NTC) thermistors embedded in its structure. Located near coil hot- spots, these provide monitoring of internal temperatures and allow the imaging system to shut down in the event of gradient overheating.

Two extra sensors allow monitoring of the water inlet and outlet temperatures for reference.

Connection to the sensors is through the single Thermometry connector. Usually this is panel- mounted on the service end flange, but on some systems it is cable- mounted on the end of a fly- lead.

Pin assignments are shown in Table 6, along with those of Agilent standard Discovery thermistor cable (part number C0749).

Table 5 RT shim pin assignments

Shim Pins Wire ident (C0751)

Pins (C0751)

Z0 1 24 1

2 23 2

Z2 3 22 5

4 21 6

ZX 9 16 17

10 15 18

ZY 11 14 19

12 13 20

XY 13 12 27

14 11 28

X2-Y2 15 10 25

16 9 26

screen backshell screen 37

CAUTION Never operate the gradient without an appropriate temperature monitoring interlock.

Installation 3


Gradient identity (Gradient ID)

To enable the MRI system to automatically recognize which gradient coil is connected, each coil has its Gradient ID encoded on the thermometry connector.

Table 6 Temperature sensor pin assignments

Sensor Location Pins Wire (C0399) Pins (0399)

1 -ve Primary X 1 R 1

1 +ve 9 O 20

2 -ve Primary X 2 BE 2

2 +ve 10 PK 21

3 -ve Primary Z 3 GN 3

3 +ve 11 T 22

4 -ve RT shims 4 Y 4

4 +ve 12 GY 23

5 -ve Shield X 5 W 5

5 +ve 13 R/BE 24

6 -ve Shield X 6 BK 6

6 +ve 14 GN/R 25

7 -ve Water inlet 7 BN 7

7 +ve 15 Y/R 26

8 -ve Water outlet 8 V 8

8 +ve 16 W/R 27

ID0 --- 17 R/BK 18

ID1 --- 18 R/BN 36

ID2 --- 19 Y/BE 19

ID +5V --- 20 W/BE 37

screen backshell screen backshell


3 Installation

Cooling Water Installation

The water cooling system is connected via two quick connect couplings. These couplings are usually panel mounted on the service end flange, although on some systems they are mounted on the ends of hoses.

Connect the outlet first to avoid unnecessary pressurization of the gradient water system.

The cooling system can be run either open- loop or closed- loop, depending on the supply conditions. There must be a protective earth connected to the supply of an open loop or the recirculating chiller of a closed loop.

The gradient cooling systems must be drained and refilled annually. Please refer to the manual Gradient Cooling System - Flushing Procedure. Agilent gradient cooling kit (part number 5070- 0003) should be used. Filling a gradient

WARNING Protection against dangerous voltages in an insulation fault condition or coolant leak fault.To provide protection, the coolant must be demineralized water with bio-cide (Accepta 2886) and inhibitor (Accepta 2309) with resistivity ≥1MΩcm. Follow the instructions in the Agilent MRI systems manual: Gradient Cooling System - Flushing Procedure.

CAUTION Never operate the gradient coil without the minimum specified flow of cooling water.

Table 7 Water System

Wetted materials Copper, brass, stainless steel, nylon

Inlet pressure 4 bar (58 psi)

Volumetric flow rate > 3.4 liter/min

In flow temperature 10 - 20 ⁰C

Maximum coil operating temperature 60 ⁰C

Supply hose connection Swagelok SS-QC6

Supply hose internal diameter > 1/2”

Installation 3


coil cooling system typically requires 1 kit; chillers with large reservoirs might require more kits.

In order to prevent damage or contamination of the gradient coil, be aware of the following recommendations:

• Never run the gradient without an adequate flow of cooling water.

• Use demineralized (not deionized) water with a resistivity of ≥1MΩcm.

• Use 1ml Accepta 2886 biocide per 5 liters of demineralized water.

• Use 150ml Accepta 2309 inhibitor per 5 liters of demineralized water.

• On open- loop systems, use a water filter is upstream of the gradient coil.

• On closed- loop systems, add a biocide to the water to prevent algae and bacteria build up. A water filter upstream of the gradient coil is recommended.

• Adhere to the chiller/heat exchanger manufacturer instructions.

• Drain and refill the gradient cooling system annually following the procure in the manual gradient Cooling System - Flushing Procedure.


3 Installation


© Agilent Technologies, Inc.

Printed in USA, 2015

*9100379800*

9100379800, Rev B, October 2015

In this book

This manual contains technical reference information about the Agilent Discovery 205/120 HD Gradient Coil.

The manual describes the following:

• introduction

• product description

• safety

• system specifications

• installation

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