Leo Szilard's papers to be online

"UCSD to digitize Szilard papers"

by

Gary Robbins

February 5th, 2014

The San Diego Union-Tribune

UC San Diego's Geisel Library has received a grant of nearly $100,000 to digitize the papers and materials of Leo Szilard, the late physicist whose work on nuclear chain reactions helped lead to the Manhattan Project, the program that produced the country's first atomic bombs.

The library's Mandeville Special Collections has more than 50,000 items involving Szilard, who spent part of the 1950s as a consultant at General Atomics in San Diego before going on to become one of the first fellows at the Salk Institute of Biological Sciences in La Jolla. Szilard, who had a deep interest in biology as well as physics, died in La Jolla in May 1964 at the age of 66.

The National Historical Publications and Records Commission gave the grant to the University of California San Diego, whose library also houses major collections of papers from Nobel laureates Francis Crick, Harold Urey and Maria Goeppert Mayer, polio vaccine developer Jonas Salk, and children's author Theodor Seuss Geisel.

"The public is going to have access not only Szilard's creations, but to documents that show the process of that creation," said William Lanouette of San Diego, author of "Genius in the Shadows: A Biography of Leo Szilard, the Man Behind the Bomb."

Lanouette will give a public speech about Szilard's life and career on March 5th at the UC San Diego Faculty Club, starting at 11 a.m.

Szilard changed the course of history in 1933 when he came up with the basic idea for nuclear chain reaction, which he later patented with physicist Enrico Fermi. Six years later, Szilard worked with Albert Einstein on a draft of a letter to President Franklin D. Roosevelt that specified how the breakthrough might be used to develop nuclear weapons. A formal later was later sent to Roosevelt, leading to the creation of the Manhattan Project.

Szilard was a major behind-the-scenes contributor to the project. But he ended up lobbying the government hard against using atomic bombs against Japan, a campaign that proved to be unsuccessful.

Einstein was not poor

Einstein wasn't a poor man for he garnered a few bucks from the Nobel Prize [which was shared or given to Mileva], lectures, teaching, and "patents"--yes, good ole "patents". Some were shared with his old colleague Leo Szilard.

Switzerland:

1930: 140217(17a)--Kaeltemaschine with Leo Szilard

Germany:

1932: 554 959(17a,3)--Kaeltemaschine with Leo Szilard
555 413(17a,3)--Kaeltemaschine with Leo Szilard
556 535(17a,3)--Kaeltemaschine with Leo Szilard
561 904(17a,3)--Kaeltemaschine with Leo Szilard
562 300(17a,1)--Kaeltemaschine with Leo Szilard
563 403(17a,3)--Kaeltemaschine with Leo Szilard
565 614(17a,3)--Kompressor with Leo Szilard
562 040(21d2,18)--Elektromagnetische Vorrichtung zur Erzeugung einer oszillierenden, Bewegung with Leo Szilard

1933: 590 783(21a2,1/04)--Vorrichtung,insbesondere fur Schallwiedergabegeraute with Rudolf Goldschmidt

The United States:

1930: 1,781,541--Refrigeration with Leo Szilard

1936: 2,058,562--Light intensity self-adjusting camera with Gustav Backy

Sample patent:

United States Patent

2,058,562

Oct. 27, 1936

GUSTAV BUCKY, NEW YORK, N. Y., AND
ALBERT EINSTEIN, PRINCETON, N. J.

LIGHT INTENSITY SELF-ADJUSTING CAMERA

Application December 11,1935. Serial No.53,884

9 Claims.(Cl.95-10)

This invention relates to a camera with a device for automatically adjusting the light intensity, and an object of the invention is to provide means for automatically adapting the light impinging the photographic plate or film of the camera to the light intensity of the surroundings and particularly of the object to be photographed.

A further object the invention is to provide means for an automatic adjustment of the light intensity without necessitating the use of a power source which may be due to get exhausted after a certain length of time, like an electric battery.
The invention consists in the combination of a camera with a photo-electric cell and a screen of varying penetrability to light, said screen being movable in the path of the light rays passing the camera objective.

Further objects, features and details will be apparent from the following description and the accompanying drawing illustrating an embodiment of the invention. In the drawing are:

Fig.1 a side elevation of a portion of a camera as per the invention, partly in section,
Fig.2 a front elevation of the camera,
Fig.3 a front elevation of a modified part,
Fig.4 an elevation of the screen.

Referring now to the figures, 10 is a camera having a front wall 11, which carries the photographic objective 12 with lenses 13 and 14. In the interior of the camera 10, a photo-electric cell forming a unit 15 together with a mechanism for turning a shaft is mounted and secured to the camera by suitable means, as for instance by means of a bracket 19. Such photo-electric cell with the mentioned mechanism for turning a shaft, which may be for instance a mechanism as conventional in a millivoltmeter, is a well-known unit available on the market and is used in exposure meters where the shaft carries a pointer for indicating the correct length of exposure, as for instance the "Weston Photronic photo-electric cell". This photo-electric cell unit 15 per se does not form part of the present invention and is therefore shown merely in its outlines. 16 is the shaft adapted to be actuated by said photo-electric cell unit. The unit 15 receives light through a tubular fixture 17 in front wall 11 with or without the help of a lens 18 in the aperture of fixture 17. With shaft 16, a member 20 is rigidly connected,@which comprises two radical arms 21 and 22. A screen 23 having the shape of a ring segment is stretched between the ends of arms 21 and 22 and secured to these arms for instance by means of rivets 24. Screen 23 is made of a transparent, preferably of a celluloid-like material. The transparency of the screen is decreased from one end to the other, from its maximum to a minimum. This is done by shading it from clear over gray to black as indicated in Fig.4. This screen is so arranged that it may swing in the path of the light rays passing through objective 12, and it is furthermore so arranged that the screen portion with maximum transparency is in the path of the rays when the photo-electric cell is not or only very little energized, that means when the light intensity is weakest. The plane in which the screen intersects these light rays is immaterial. We, however, prefer to position the screen between the lenses 13 and 14 for which purpose the objective tube 25 is slitted at 26, because the coincidence of the rays in the space between the lens permits the screen to be made very narrow. This is important because the movable parts in connection with unit 15 should be made as light as possible in consideration of the very small power output of a photo-electric cell. It is, however, within the scope of this invention to use another kind of photo-sensitive cells as for instance a selenium cell with a battery.

It will be understood that the camera according to our invention may be equipped with any conventional accessorial parts as for instance a shutter, omitted in the drawing in order to avoid overcrowding of lines.

If now the camera is directed with its objective 12 upon the object to be photographed, the aperture or light entrance tube 17 of the photo-electric unit is directed likewise. The light intensity striking the photo-electric unit creates a power which turns the shaft 16 through an angle which is a function of the light intensity. Consequently, the screen 23, is swung between lenses 13 and 14 in such a position that the light impinging the photographic plate or film is adjusted in correspondence with the light entering the photo-electric unit. It is obvious that the increment of alteration of the transparency has to be so chosen from the start, that it corresponds with the angles through witch the shaft 16 is turned due to the light intensity, and that it also corresponds with the light desired to impinge the photographic plate.

If a camera is equipped with the device as described, no iris for light reduction is required. In many instances, however, it may be desirable to have different diaphragms or a variable diaphragm for the objective in the conventional manner, and to use the automatic adjuster only for taking care of such alterations of the light which occur after the camera has been set for taking a photograph with a definite shutter speed. This may be the case particularly with cinematographic cameras. It also may be desirable to voluntarily alter the aperture of the objective in correspondence with the sensitivity of the emulsion of the film or plate used in each particular case. If, however, the aperture of the objective is variable in a voluntary manner, the self-adjusting device may not always produce proper correction for the alterations of the light. In order to overcome such drawbacks, we provide means for simultaneously and proportionally altering the aperture of the objective and the aperture through which the light enters the photo-electric cell. In figs.1 and 2 a very simple arrangement of this kind is illustrated. A disc 28 is pivotally mounted at 28' on the front wall 11, between the objective 12 and the tube 17. Objecti‚–‚… 12 and tube 17 are slitted at 29 and 30 respectively and the disc 28 passes through such slits. Disc 28 is provided with a set of holes 31a, 31b and 31c of different sizes and with a second set of holes 32a, 32b and 32c, which are so arranged that hole 31a is in front of objective 12 when hole 32a is in front of tube 17. The same relation exists with regards to holes 31b and 32b and holes 31c and 32c. The sizes of these sets of holes are so chosen that the second one is adapted to change the aperture of tubular fixture 17 in the same proportion as the first set is adapted to change the aperture of the objective 12. Thus the unit 15 receives light only in correspondence with the light of the objective and may now properly correct the light impinging the photographic plate. In a similar manner, when using a filter for the objective, a filter of equal quality should be used for the light entrance to the photo-electric cell. In such a case a disc 128 may be provided or substituted for disc 28, which contains corresponding sets of holes, 131a, b, c and 132a, b, c filled with filter substances, such as for instance colored glass. The holes of one set may then be of equal size, but the filter substances of the holes of each of the sets may be of different filtering qualities, or they may be of different size as shown.

Although a particular embodiment of the invention has been illustrated and described herein, it will be obvious to those skilled in the art, that various modifications may be made in the details of the construction without departing from the principle herewith set forth.

We claim:

1. In combination with a camera having an objective, a shaft and a photo-electric cell unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a ring segment shaped screen of a transparency decreasing from one of its ends to the other end, rigidly connected with said shaft and adapted to swing in the path of the light rays passing said objective.
2. In combination with a camera having an objective, a shaft and a photo-electric cell unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a ring segment shaped screen of a transparency decreasing from one of its ends to the other end, and a two-armed screen carrier rigidly connected with said shaft, said screen stretched between the ends of said carrier arms and adapted to swing in the path of the light rays passing said objective.
3. In a combination as claimed in claim 2, said screen being of transparent material increasingly darkened from its one end to the other end.

4. A camera comprising an objective including a first lens, a second lens and a tubular mount for said lenses; a shaft, a photo-electric cell unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a segment shaped screen of a transparency decreasing from one of its ends to the other end and rigidly connected with said shaft, and a slit in said tubular mount between said first and said second lens, said screen being adapted to swing within said slit.
5. In a camera having a front wall, an objective in said front wall, a shaft, a photo-electric cell unit, means in the camera front wall for admitting light to said photo-electric cell unit, said unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a segment shaped screen of a transparency decreasing from one of its ends to the other end, rigidly connected with said shaft and adapted to swing in the path of the light rays, passing said objective and manually operated means for simultaneously altering the aperture of said objective and the aperture of said light admitting means.

6. In a camera having a front wall, an objective in said front wall, a shaft, a photo-electric cell unit, means in the camera front wall for admitting light to said photo-electric cell unit, said unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a segment shaped screen of a perviousness to light decreasing from one of its ends to the other end, rigidly connected with said shaft and adapted to swing in the path of the light rays passing said objective, and manually operated light filtering means adapted to equally and simultaneously alter the quality of the light rays passing said objective and said light admitting means.

7. In a camera having an objective, a photo-electric cell unit, two screens of a transparency decreasing from one screen end to the other end, said screens being arranged one in front of the other one, the end with greatest transparency of one screen towards the one side and that of the other screen towards the other side, said screens being movable in the path of the light rays passing said objective, and means under the control of said photo-electric cell unit for moving said screens simultaneously equal distances in opposite directi‚ns.

8. In a camera having an objective, a photo-electric cell unit, a screen of a transparency decreasing from one of its end to the other end, said screen being movable in the path of the light rays passing through said objective, and means under the control of said photo-electric cell unit for moving said screen in response to the prevailing light conditions whereby the transparency of the screen area in the path of the light rays passing the objective decreases when the light impinging said cell unit increases from a minimum to a maximum.

9. In a camera having a front wall, an objective in said front wall, a shaft, a photo-electric cell unit, means in the camera front wall for admitting light to said photo-electric cell unit, said unit including a drive for oscillating said shaft in correspondence with the variation of the light impinging the photo-electric cell, a segment shaped screen of a perviousness to light decreasing from one of its ends to the other end, rigidly connected with said shaft and adapted to swing in the path of the light rays passing said objective, manually operated means for simultaneously altering the aperture of said objective and the aperture of said light admitting means, and light filtering means for equally and simultaneously altering the quality of the light rays passing said objective and said light admitting means.

GUSTAV BUCKY.
ALBERT EINSTEIN.


The refrigerator:

"It's noiseless, inexpensive and durable. But reinventing the great genius' invention may not be the answer to one of today's environmental problems. Then again, it may be."

"Einstein's Refrigerator"

Book:

"Whatever happened to the refrigerator Einstein helped invent' While it never became a commercial success, its underlying concepts became the basis for cooling nuclear breeder reactors."

Einstein's Refrigerator...

ISBN: 0740714198

Historical event in 1942 at the University of Chicago

"The problems posed by this world situation are not for the scientist alone but for all people to resolve. Perhaps a time will come when all scientific and technical progress will be hailed for the advantages that it may bring to man, and never feared on account of its destructive possibilities."

This is the last entry by Enrico Fermi describing the first controlled and self-sustaining nuclear chain reaction at the University of Chicago in 1942. Good thoughts and intentions repeated by many with little fruition. I wonder if Alfred Nobel said something similar with the introduction of nitroglycerine?

University of Chicago
West Stands of Stagg Field
December 2nd, 1942

First Controlled, Self-sustaining Nuclear Chain Reaction as described by Enrico Fermi

It is ten years since man first achieved a self-sustaining atomic reaction.

Many people link this event only with the development of the atomic bomb and the subsequent efforts to develop the hydrogen bomb, reference to which has been made in the last few days by the Atomic Energy Commission.

The history of the first self-sustaining nuclear chain reaction, like that of all scientific achievements, begins with man's first philosophical speculations about the nature of the universe. Its ultimate consequences are still unpredictable.

The sequence of discoveries leading to the atomic chain reaction was part of the search of science for a fuller explanation of nature and the world around us. No one had any idea or intent in the beginning of contributing to a major industrial or military development.

A partial list of the main stepping-stones to this development indicates many countries contributed to it.

The story begins in Paris in 1896 when Antoine Henri Becquerel discovered the existence of radioactive elements; that is, elements which spontaneously emit invisible, penetrating rays. Two years later, also in Paris, Pierre and Marie Cure discovered radium, for many years the best known of the radioactive elements.

In Zurich, Switzerland, in 1905, Albert Einstein announced his belief that mass was equivalent to energy. This led to speculation that one could be transformed into the other.

A most important discovery came in 1912 when Ernest Rutherford discovered the minute but heavy nucleus which forms the core of the atom. In ordinary elements this core is stable; in radioactive elements it is unstable.

Shortly after World War I, the same Rutherford achieved for the first time the artificial disintegration of the nucleus at the center of the nitrogen atom.

During the next decade, research progressed steadily, if unspectacularly. Then, in 1932, came a series of three discoveries by scientists working in three different countries which led to the next great advance.

Walter Bothe in Germany, and Frederic Joliot-Curie in Paris prepared the ground work that led James Chadwick of England to the discovery of the neutron. The neutron is an electrically neutral building block of the nuclear structure. The other build block is the positively charged proton.

The next step was taken in Rome in 1934. In experiments in which I was concerned it was shown that these neutrons could disintegrate many atoms, including those of uranium. This discovery was to be directly applied in the first atomic chain reaction eight years later.

The Discovery of Fission

The final stepping-stone was put in place in Berlin when Otto Hahn, working with Fritz Strassman, discovered fission or splitting of the uranium atom. When Hahn achieved fission, it occurred to many scientists that this fact opened the possibility of a form of nuclear (atomic) energy.

The year was 1939. A world war was about to start. The new possibilities appeared likely to be important, not only for peace but also for war.

A group of physicists in the United States‹including Leo Szilard, Walter Zinn, now director of Argonne National Laboratory, Herbert Anderson, and myself‹agreed privately to delay further publications of findings in this field.

We were afraid these findings might help the Nazis. Our action, of course, represented a break with scientific tradition and was not taken lightly. Subsequently, when the government became interested in the atom bomb project, secrecy became compulsory.

Here it may be well to define what is meant by the "chain reaction" which was to constitute our next objective in the search for a method of utilizing atomic energy.

An atomic chain reaction may be compared to the burning of a rubbish pile from spontaneous combustion. IN such a fire, minute parts of the pile start to burn and in turn ignite other tiny fragments. When sufficient numbers of these fractional parts are heated to the kindling points, the entire heap bursts into flames.

A similar process takes place I an atomic pile such as was constructed under the West Stands of Stagg Field at The University of Chicago in 1942.

The pile itself was constructed of uranium, a material that is embedded in a matrix of graphite. With sufficient uranium in the pile, the few neutrons emitted in a single fission that may accidentally occur strike neighboring atoms, which in turn undergo fission and produce more neutrons.

These bombard other atoms and so on at an increasing rate until the atomic "fire" is going full blast.

The atomic pile is controlled and prevented from burning itself to complete to complete destruction by cadmium rods which absorb neutrons and stop the bombardment process. The same effect might be achieved by running a pipe of cold water through a rubbish heap; by keeping the temperature low the pipe would prevent the spontaneous burning.

The first atomic chain reaction experiment was designed to proceed at a slow rate. In this sense it differed from the atomic bomb, which was designed to proceed at as fast a rate as was possible. Otherwise, the basic process is similar to that of the atomic bomb.

The atomic chain reaction was the result of hard work by many hands and many heads. Arthur H. Compton, Walter Zinn, Herbert Anderson, Leo Szilard, Eugene Wigner and many others worked directly on the problems at The University of Chicago. Very many experiments and calculations had to be performed. Finally a plan was decided upon.

Thirty "piles" of loss than the size necessary to establish a chain reaction were built and tested. Then the plans were made for the final test of a full-sized pile.

The scene of this test at The University of Chicago would have been confusing to an outsider‹if he could have eluded the security guards and gained admittance.

He would have seen only what appeared to be a crude pile of black bricks and wooden timbers. All but one side of the pile was obscured by a balloon cloth envelope.

As the pile grew toward its final shape during the days of preparation, the measurement performed many times a day indicated everything was going, if anything, a little bit better than predicted by calculations.

The Gathering on the Balcony

Finally, the day came when we were ready to run the experiment. We gathered on a balcony about 10 feet above the floor of the large room in which the structure had been erected.

Beneath us was a young scientist, George Weil, whose duty it was to handle the last control rod that was holding the reaction in check.

Every precaution had been taken against an accident. There were three sets of control rods in the pile. One set was automatic. Another consisted of a heavily weighted emergency safety held by a rope. Walter Zinn was holding the rope ready to release it at the least sign of trouble.

The last rod left in the pile, which acted as starter, accelerator and brake for the reaction, was the one handled by Weil.

Since the experiment had never been tried before, a "liquid control squad" stood ready to flood the pile with cadmium salt solution in case the control rods failed. Before we began, we rehearsed the safety precautions carefully.

Finally, it was time to remove the control rods. Slowly, Weil started to withdraw the main control rod. On the balcony, we watched the indicators which measured the neutron count and told us how rapidly the disintegration of the uranium atoms under their neutron bombardment was proceeding.

At 11:35 a.m., the counters were clicking rapidly. Then, with a loud clap, the automatic control rods slammed home. The safety point had been set too low.

It seemed a good time to eat lunch.

During lunch everyone was thinking about the experiment but nobody talked much about it.

At 2:30, Weil pulled out the control rod in a series of measured adjustments.

Shortly after, the intensity shown by the indicators began to rise at a slow but ever-increasing rate. At this moment we knew that the self-sustaining reaction was under way.

The even was not spectacular, no fuses burned, no lights flashed. But to us it meant that release of atomic energy on a large scale would be only a matter of time.

The further development of atomic energy during the next three years of the war was, of course, focused on the main objective of producing an effective weapon.

At the same time we all hoped that with the end of the war emphasis would be shifted decidedly from the weapon to the peaceful aspects of atomic energy.

We hoped that perhaps the building of power plants, production of radioactive elements for science and medicine would become the paramount objectives.

Unfortunately, the end of the war did not bring brotherly love among nations. The fabrication of weapons still is and must be the primary concern of the Atomic Energy Commission.

Secrecy that we thought was an unwelcome necessity of the war still appears to be an unwelcome necessity. The peaceful objectives must come second, although very considerable progress has been made also along those lines.

The problems posed by this world situation are not for the scientist alone but for all people to resolve. Perhaps a time will come when all scientific and technical progress will be hailed for the advantages that it may bring to man, and never feared on account of its destructive possibilities.