Performance of a helium circulation system for a MEG

被引：7

作者：

Takeda, Tsunehiro ^{[1
]}

Okamoto, Masayoshi ^{[1
]}

Atsuda, Kazuhiro ^{[1
]}

Katagiri, Keishi ^{[1
]}

机构：

[1] Univ Tokyo, Grad Sch Frontier Sci, Dept Complex Sci & Engn, Chiba 2778561, Japan

来源：

CRYOGENICS | 2009年 / 49卷 / 3-4期

关键词：

Liquid helium; SQUIDS; Gifford-McMahon; Cryostats; Reuse;

D O I：

10.1016/j.cryogenics.2008.12.001

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

We report the performance of a helium circulation system (HCS) for a magnetoencephalography (MEG) that re-liquefies all the evaporating helium gas using two 1.5 W GM cryocoolers operating at 4.2 K. The MEG with the HCS was used to measure human brain responses for over one and a half years without any noise problems. The noise level is below 10 fr/Hz(1/2) for 2-40 Hz, below 30 fr/Hz(1/2) at 1 Hz, and 200 IT/Hz(1/2) at 50 Hz, which is the power supply frequency. As the amount of liquid helium used decreases less than one percent, the maintenance cost of the MEG becomes less than one-tenth of the previous cost. (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：144 / 150

页数：7