CT球管的保养与维护（二-上）

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                    <p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; text-align: center; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><span style="max-width: 100%; font-size: 18px; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="max-width: 100%; font-size: 24px; box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">旋转阳极球管</strong></span></span><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">旋转阳极球管是在大功率<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>光机出现以后出现的一种高性能的球管，这种球管能在小的焦 点下使用更大的电流进行工作，从金属散热的角度分析，任何金属对热的传导都有热阻，球管在小焦点大电流工作的情况下，在阳极靶面会产生高温，如果电子束固 定在一个位置不断的轰击，靶面很快就会熔化，如果我们让靶面活动起来，是电子束不断的变换轰击位置，就可以是球管在更大的电流下工作，使靶面受到电子束轰 击的位置产生的热量有足够的时间向金属内部传导，靶面就不会出现熔化问题。需要说明的是，<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>线球管的阳极工作在真空中，散热条件很差，它的散热方式主要是 以辐射的方式散出，现在大功率球管在曝光时的功率可以达到<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">60</span>千瓦以上，其中<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">99.5%</span>的功率变成了热，只有<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">0.5%</span>的功率转变为<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>射线，所有的热都会留 在阳极上，散热对旋转阳极球管来说尤其重要。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><br  /></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">（一）<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">.</span>旋转阳极的转速，目前的球管旋转阳极转速都在<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">3000</span>转以上，高速旋转阳极球管可达到<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">7200</span>转，超高速的球管目前可达到<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">1</span>万转以上，球管阳极的转速是根 据球管的焦点电流密度设计的，同样管电流的球管，焦点越小，要求球管旋转阳极的转速越高。对于应用来说，球管的焦点越小，性能越好，这是因为焦点越小，所 投射的半影也越小，所得到的图像也越清晰，但球管的制造难度也越大。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><br  /></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">（二）<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">.</span>旋转阳极球管的结构与固定阳极球管的结构差别主要是在阳极上，旋转阳极是一 个带轴的圆盘，根据不同的用途选用不同的靶面材料，<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">CT</span>机球管采用的是钨靶，为了提高整体的散热能力，靶面材料被镶嵌在钼基的盘座上，大功率的球管，为了 减轻旋转靶及整个球管的重量，提高球管的热容量，在靶盘的背面用钎焊的方法加上一定厚度和质量的石墨基，整个靶通过轴承固定在管芯支架上，旋转阳极使整个 球管技术含量最高的部分。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">球管是一个真空电子管，在很高的工作电压下工作，对球管内的真空要求很高，这就要求球管内的所有部件在球管封装前，必须作严格的脱氧及除气处理，这样才能保证成品球管的真空度。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">阳极的旋转是靠加在管芯外面电机定子线圈产生的旋转磁场进行驱动，所说的旋转阳极的轴，实际上是一个磁滞式电动机的转子，只不过它是被密封在真空里。旋转阳极的功能是在电子束流的轰击下产生<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>射线。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">阳极在电子束流的轰击下，在阳极的表面会留下电子束轰击的轨迹，阳极在旋转方面的任何故障，都会造成阳极表面的损伤，阳极表面金属的熔化会产生金属蒸汽，使靶面烧伤产生沟痕，改变<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>射线的品质和<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">X</span>射线的出线方向，并且破坏球管内的真空，造成球管的内部打火，使球管报废。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><br  /></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">（三）<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">.</span>旋转阳极球管的阴极是一个直热式真空管的阴极，它的灯丝由钨制成，旁边加有控制电子射线角度和方向的束流罩，用它来控制球管焦点的大小，双焦点的球管有两组这样的灯丝阴极。阴极的功能是产生电子束流来轰击阳极。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; line-height: 25.6px; white-space: normal; text-indent: 24pt; box-sizing: border-box !important; word-wrap: break-word !important; background-color: rgb(255, 255, 255);"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">阴极的灯丝是在高温下工作的，长期的工作会使灯丝的金属挥发，在电子束发射的过程中 也会有部分的灯丝金属离子随着电子束流被发射到阳极上面，因为阴极电流是从灯丝上发射出去的，而从灯丝上蒸发出来的金属气体，也会使球管真空度下降，出现 打火故障，无论是阳极还是阴极蒸发出来的金属气体，都会像水蒸气一样在球管较冷玻壳上的凝聚，使球管的玻壳像用久了的电灯泡一样变成黑色。<span lang="EN-US" style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><o:p style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></o:p></span></strong></p><p style="max-width: 100%; min-height: 1em; color: rgb(62, 62, 62); font-family: &#39;Hiragino Sans GB&#39;, &#39;Microsoft YaHei&#39;, Arial, sans-serif; font-size: 16px; white-space: normal; line-height: 26px; box-sizing: border-box !important; word-wrap: break-word !important; background: white;"><strong style="max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="max-width: 100%; font-family: 宋体; box-sizing: border-box !important; word-wrap: break-word !important;">后续内容请关注，将陆续发出！</span></strong></p><p><br  /></p>