Integrated Atom Detector Based on Field Ionization near Carbon Nanotubes
Integrated Atom Detector Based on Field Ionization near Carbon Nanotubes
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基于碳纳米管附近场电离的集成原子探测器
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Fortágh
中科院分区：
文献类型：
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作者：
B. Grüner;M. Jag;A. Stibor;G. Vişănescu;M. Häffner;Dieter P. Kern;A. Günther;J. Fortágh
我们展示了一个基于场电离和随后的离子计数的原子探测器。我们利用碳纳米管尖端附近的电场增强，达到高达9 × 10 {sup 9} V/m的极端静电场值，从而抑制基态铷原子。该探测器是基于一个地毯的多壁碳纳米管生长在基板上，用于场电离，和一个通道电子倍增器用于离子计数。利用场致电子发射测量了碳纳米管尖端的场增强效应。我们演示了场电离检测器的操作，通过计数原子从热束的铷分配器源。通过测量铷的电离率作为所施加的检测器电压的函数，我们确定了场电离距离，其在纳米管尖端前方低于几十纳米。我们从实验数据中推断出，纳米管尖端附近的铷的场电离发生的时间尺度快于10{sup-10} s。这一特性对于发展适用于测量超冷量子气体相关性的快速原子探测器特别有意义。我们还描述了该探测器作为分压计的应用。
We demonstrate an atom detector based on field ionization and subsequent ion counting. We make use of field enhancement near tips of carbon nanotubes to reach extreme electrostatic field values of up to 9x10{sup 9} V/m, which ionize ground-state rubidium atoms. The detector is based on a carpet of multiwall carbon nanotubes grown on a substrate and used for field ionization, and a channel electron multiplier used for ion counting. We measure the field enhancement at the tips of carbon nanotubes by field emission of electrons. We demonstrate the operation of the field ionization detector by counting atoms from a thermal beam of a rubidium dispenser source. By measuring the ionization rate of rubidium as a function of the applied detector voltage we identify the field ionization distance, which is below a few tens of nanometers in front of nanotube tips. We deduce from the experimental data that field ionization of rubidium near nanotube tips takes place on a time scale faster than 10{sup -10} s. This property is particularly interesting for the development of fast atom detectors suitable for measuring correlations in ultracold quantum gases. We also describe an application of the detector as partial pressure gauge.