The image quality in a MRI magnet greatly depends on the mechanical, thermal and electromagnetic performance of the thermal shield in presence of any time varying field. A detailed analysis on the mechanical resonance frequency, temperature distribution and the eddy current distribution on a thermal shield of a zero-boil-off cryostat for 1.5T MRI magnet system is presented. Five combination of aluminum alloys using AA1100, AA5083-O, AA6061-T6 are considered for the analysis. The mechanical natural resonance frequency of shield is studied for its various length and the radial thickness varying in the range of 1–10 mm of the thermal shield. The resonance frequency of the AA1100 bore tube is found to varying in the range of 1.9–5.2 kHz. The overall temperature non-uniformity of 8.5 K is achieved in the binary shield made of AA1100 for the outer shell and the bore tube and AA6061-T6 for the endplates. The temperature non-uniformity achieved in the imaging length of 45 cm of the bore tube is 0.034 K. The eddy current induced along the imaging length of the bore tube is 1.7% of the peak eddy current onto the shield during a quench in the magnet. The highest eddy current of ~2490 A/cm² is generated on the bore tube for the binary shield made of AA1100 for the outer shell and the bore tube and AA5083-O for the endplates.

MRI磁体中的图像质量在很大程度上取决于存在任何时变场的情况下隔热屏的机械，热和电磁性能。详细分析了用于1.5T MRI磁体系统的零沸腾低温恒温器的热屏蔽罩上的机械共振频率，温度分布和涡流分布。分析使用AA1100，AA5083-O，AA6061-T6的五种铝合金组合。研究了热屏蔽的各种长度和径向厚度在热屏蔽的​​1-10 mm范围内变化的机械自然共振频率。发现AA1100内孔管的共振频率在1.9–5.2 kHz范围内变化。整体温度不均匀度为8。在外壳和孔管由AA1100制成的二元屏蔽罩和在端板由AA6061-T6制成的二元屏蔽罩可达到5K。在腔管45厘米的成像长度中实现的温度不均匀度为0.034K。沿腔管的成像长度感应的涡流是磁体淬火过程中流到屏蔽罩上的峰值涡流的1.7％。 。最高涡电流〜2490 A / cm在用于外壳和孔板的AA1100制成的二元屏蔽罩的孔管上以及用于端板的AA5083-O上生成图^2所示的孔。