NMR使用序言及安全守則

NMR Usage Introduction and Safety Guidelines

Welcome to the NMR instrument usage training course. Before we begin, let’s briefly introduce the three main components of an NMR instrument: the magnet, the electronic system, and the computer.

Basic Components of the NMR Instrument

1.     Magnet
The superconducting magnet of the NMR instrument has a cylindrical appearance. This is a 400 MHz NMR (approximately 9.4 Tesla) superconducting magnet. The magnet was charged during installation and, under proper liquid nitrogen and liquid helium cooling, its magnetic field can be maintained indefinitely. The magnet is always on, regardless of whether an experiment is in progress.

2.     Electronic System (Console)
The console includes an RF transmitter, detector, temperature controller, and signal processor, which generate and transmit RF pulses used for experiments. These pulses are sent via cables to the probe inside the magnet.

3.     Computer (Workstation)
The computer operates the NMR software (Topspin), which connects and controls the magnet and electronic system, handles experiment setup, and processes experimental data.

BBFO Probe Introduction

This instrument is equipped with a BBFO (Broadband with Fluorine Observe) probe, designed for broadband dual-channel operation.

• The outer coil detects ¹H frequencies, while the inner coil covers broadband frequencies from ¹⁹F to ¹⁵N.

• It is equipped with gradient coils, a heating device, and an automated tuning and matching system (ATM).

• The ATM, a small motor located at the bottom of the probe, is highly precise and sensitive. Commands like atmm should be executed with caution, as any damage requires repair by the original manufacturer.

• The probe is suitable for most heteronuclear, two-dimensional, and variable-temperature experiments (both high and low temperature). Training is required for variable-temperature experiments; please contact the administrator for assistance.

Safety Guidelines

The safety guidelines for the NMR room focus on two main areas: the magnet and the sample tube.

1.     Magnet Safety

·         Magnetic Field Precautions
People with pacemakers, metallic implants, or metal accessories are strictly prohibited from entering the NMR room. Items like credit cards, magnetic cards, mobile phones, cameras, and metallic tools must be kept outside the 5 Gauss line to prevent damage or interference.

·         Magnet Quench Risks
The superconducting magnet is supported by air cushions. Strong impacts or shaking can cause liquid helium to boil. Since helium boils at only 4K, rapid vaporization may activate the safety valve, releasing a cloud of white vapor. Stay calm and leave the NMR room immediately. Although helium gas is non-toxic, its rapid release can deplete oxygen, causing dizziness or unconsciousness due to hypoxia. If the magnet undergoes a quench, repair costs can range from hundreds of thousands to millions of dollars. Handle the magnet with utmost care to avoid such incidents.

2.     Sample Tube Safety

·         Pre-Experiment Checks
Ensure that the sample tube and spinner are secure, and use a depth gauge to measure the position of the tube bottom (for the BBFO probe, it should be set at 2.0 cm). Loose or improperly positioned tubes can break inside the probe, which must be avoided.

·         Handling Breakages
If a sample tube breaks inside the probe, immediately inform the administrator so the probe can be cleaned promptly to prevent chemical contamination or damage to the probe’s coils.

Final Reminder

This instrument supports approximately 35 research groups and over 150 students. Please handle it with care, follow safety guidelines, and share this valuable resource responsibly.

NMR 使用序言及安全守則

竭誠歡迎您參加 NMR 儀器使用學習課程。在開始之前，我們將簡要介紹 NMR 儀器的三大基本組成部分：磁體、電子裝置以及電腦。

NMR 儀器的基本組成

1.         磁體

NMR 的超導磁體外型如一圓柱筒，此台為 400MHz NMR（約 9.4 Tesla）的超導磁體。磁體在裝機時已完成充磁，在液氮及液氦的冷卻保存下，磁力可以永久保持。磁鐵部分無論是否有實驗進行，都始終保持開機狀態。

2.         電子裝置（機櫃，Console）

包含 RF 發射器、偵測器、溫控器及訊號處理器等部件，負責產生及傳遞實驗用 RF 脈衝。這些脈衝經機櫃後方電纜線傳送到磁體內的探頭。

3.         電腦（工作站）

電腦上安裝了 NMR 作業程式 (Topspin)，用於連接並控制磁體及電子裝置，進行實驗控制與數據處理。

BBFO 探頭介紹

此儀器配備 BBFO（Broadband with Fluorine Observe）探頭，屬於寬頻二通道設計。

• 外圈線圈偵測 ¹H 頻率，內圈線圈可偵測 ¹⁹F 至 ¹⁵N 寬頻。

•  配置磁場梯度線圈、加熱裝置及全自動調諧系統（ATM）。

• ATM（調諧用小馬達）位於探頭下方，精密且易受損，操作指令如 atmm 時需特別小心，損壞後只能送回原廠修復。

• 適用於大部分異核實驗、二維實驗及變溫實驗（包括高溫與低溫）。進行變溫實驗需另行訓練，請聯繫管理員協助。

安全守則

NMR 室的安全守則可分為兩部分：磁鐵與樣品管的安全。

1.     磁鐵安全

• 磁場注意事項

禁止配戴心律調整器、植入金屬替代品或穿戴金屬飾品者進入 NMR 室。請將信用卡、磁卡、手機、相機、金屬工具等物品放在磁場 5 高斯（Gauss）線之外，以免受磁場影響或損壞。

• 磁體搖晃與 quench 風險

NMR 超導磁體由氣墊支撐，若受到強烈撞擊或搖晃，可能導致液氦沸騰。液氦沸點僅 4K，快速氣化將觸發安全閥，產生如雲般白煙。此時應保持冷靜，迅速離開 NMR 室。氦氣雖無毒，但若大量逸出會造成缺氧，需避免久留。磁體若發生 quench，修復費用可能高達數百萬至數千萬元，務必小心謹慎。

2.     樣品管安全

• 使用前檢查

確認樣品管及轉子是否牢固，並用深度量具（gauge）測量樣品管底部深度（對 BBFO 探頭，應置於 2.0cm）。樣品管鬆動或深度不準確，易在探頭內破裂，應盡量避免。

• 破損處理

若樣品管在探頭內破裂，請立即通知管理員，以便快速清理探頭，避免化學污染或腐蝕探頭線圈。

最後提醒

此台儀器支援約 35 個研究群，超過 150 名學生使用，請大家共同愛護，安全操作，共享儀器資源。