曼哈顿计划的背景
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发布时间：2022-04-21 20:23
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热心网友
时间：2023-09-10 13:23
到1941年12月6日，美国正式制定了代号为“曼哈顿”的绝密计划。 罗斯福总统赋予这一计划以“高于一切行动的特别优先权”。
1937年2月，纳粹德国开始执行了“铀计划”。1941年末，珍珠港事件后，美国参加了二次大战，与纳粹德国宣战。一些美国科学家提议要先于纳粹德国制造出原子弹。
例如爱因斯坦给罗斯福的原信如下：
Albert Einstein
Old Grove Rd.
Nassau Point
Peconic, Long Island
August 2nd, 1939
F.D. Roosevelt
President of the United States
White House
Washington, D.C.
Sir:
Some recent work by E.Fermi and L. Szilard, which has been communicated to me in manuscript, leads me to expect that the element uranium may be turned into a new and important source of energy in the immediate future. Certain aspects of the situation which has arisen seem to call for watchfulness and, if necessary, quick action on the part of the Administration. I believe therefore that it is my ty to bring to your attention the following facts and recommendations:
In the course of the last four months it has been made probable – through the work of Joliot in France as well as Fermi and Szilard in America – that it may become possible to set up a nuclear chain reaction in a large mass of uranium by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future.
This new phenomenon would also lead to the construction of bombs, and it is conceivable – though much less certain – that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory. However, such bombs might very well prove to be too heavy for transportation by air.
The United States has only very poor ores of uranium in moderate quantities. There is some good ore in Canada and the former Czechoslovakia, while the most important source of uranium is Belgian Congo.
In view of the situation you may think it desirable to have more permanent contact maintained between the Administration and the group of physicists working on chain reactions in America. One possible way of achieving this might be for you to entrust with this task a person who has your confidence and who could perhaps serve in an inofficial capacity. His task might comprise the following:
a) to approach Government Departments, keep them informed of the further development, and put forward recommendations for Government action, giving particular attention to the problem of securing a supply of uranium ore for the United States;
b) to speed up the experimental work, which is at present being carried on within the limits of the budgets of University laboratories, by providing funds, if such funds be required, through his contacts with private persons who are willing to make contributions for this cause, and perhaps also by obtaining the co-operation of instrial laboratories which have the necessary equipment.
I understand that Germany has actually stopped the sale of uranium from the Czechoslovakian mines which she has taken over. That she should have taken such early action might perhaps be understood on the ground that the son of the German Under-Secretary of State, von Weizs?cker, is attached to the Kaiser-Wilhelm-Institut in Berlin where some of the American work on uranium is now being repeated.
Yours very truly
Albert Einstein
译文如下：
阿尔伯特.爱因斯坦
老格鲁夫大街
科尼克， 长岛
1939年8月2日
F.D.罗斯福
美国总统
白宫
华盛顿特区
总统先生，
通过和E.弗尔米，I.西拉德进行关于研究草稿的交流，最近的工作使我相信在不久的将来，铀元素将成为一种新型的重要的能源。由此引起的许多问题需要我们提高警觉性，假如有必要的话，*部门应当采取迅速的行动。因此我相信我有责任提醒您关注以下的事实和建议。
在过去的四个月里，通过约里奥在法国的工作，以及弗尔米和西拉德在美国进行的工作，使用大量的铀来建立核链式反应堆，从而产生巨大的能量和大量的新型类镭元素已成为可能。现在基本可以确定这将在不久的将来实现。
这种新的现象将引导着*的构造，并且这是有可能的--尽管还不是那么确定--威力十分巨大的*将因此而可能被制造出来。这样一颗单个的*，用船运载，并在港口爆炸，将可能会摧毁整个港口以及周围的环境。然而，这样的*对于空中运输可能显得太过于沉重。
美国只有很少量适合使用的铀矿石。有一些好的矿石在加拿大和捷克斯洛伐克，但最好的铀资源还是在刚果。
基于这样的情况你也许会认为在美国建造链式反应堆的物理学家和行政部门保持永久的关系是有必要的。对于你而言实现这样的可能的方式就是，将这一任务委托给一个你信任的人，而他将以一个非官方的身份进行工作。他的任务也许包括以下内容：
1. 接近*部门，熟悉未来的发展情况，并且给*的工作提出建议，特别是关注为美国获取铀矿的供应。
2. 通过提供资金加速实验活动，解决目前由预算有限的大学实验室来进行的问题。假如已经有资金，则通过和愿意为这一事业奉献的个人联系，或者是和具有必要设备的公司实验室进行合作。
我了解到德国实际上已经停止了捷克斯洛伐克矿山的铀交易，并对其进行了接管。它已经采取这样早的行动是可以理解的，根据德国副国务卿的儿子魏茨泽克，供职于柏林凯撒--威廉研究会，而在那里美国关于铀的活动一直在重复着。
你真诚的，
阿尔伯特.爱因斯坦
1942年初，美国科学家虽然对原子弹的机制、应该努力的方向，甚至费用和时间都有了大致的构想，但核研究的庞大工程已经超过了科学研究机构的能力。当时美国经济已经转向战争，没有一家工业公司能在短期内完成有关生产设施的建设。美国核研究的负责人之一布什认为，只有军队以最高优先权，才能在战争结束前生产出核原料来。1942年3月9日，他在给罗斯福总统的报告中，强调了原子弹的光明前景，提出把全部的研制和生产管理移交给军队。6月17日，布什给罗斯福准备了一份将核计划全部交给军队领导执行的详细报告。此时罗斯福在白宫办公室里，早已研究了爱因斯坦的信，正一直举棋不定。接到布什的建议后，罗斯福立即批复了布什的报告。
