By Marshall Dudley, Tennelec/Nucleus, Oak Ridge, Tennessee, USA
and Michael Chorost, Duke University, Durham, North Carolina, USA
North American Circle
Durham, North Carolina, 27715-1144, USA
Paper completed December 31, 1991
In this paper we report the discovery of thirteen short-lived radionuclides (radioactive isotopes) in soil samples taken from an English crop circle. We will explain the significance of this discovery, rule out several mundane explanations for it (including hoax), and propose that the radionuclides were created by bombardment of the soil with deuterium nuclei (also called "deuterons.") We will also consider whether the radionuclides present a health hazard and conclude that they probably do not.
A note on terminology: we shall use the terms "isotope", "radioactive isotope", and "radionuclide" more or less interchangeably. Not all isotopes are radioactive, of course, but the ones we are discussing are. The term "radionuclide" simply means an atom whose nucleus is unstable and thus radioactive.
I. The Experimental Results
The oval-shaped crop circle (Photo 1) was formed the night of July 31 / August 1, 1991, near the town of Beckhampton.  On August 5th, we gathered two soil samples inside it and took a control several dozen feet away. Their emissions of alpha and beta particles were measured with a Tennelec/Nucleus LB4000-8 gas flow counter on August 18th. Their emissions proved to be markedly elevated, compared to the control. One sample (1A) yielded alpha emissions 198% above the control, and beta emissions 48% above the control. The other sample (1B) yielded alpha emissions 45% above the control, and beta emissions 57% above the control. 
We hypothesized that these anomalies were too large to ascribe to normal soil variation. This was supported by the fact that two controls from another formation in the area (formed August 9/10, SU 076 679) yielded alpha and beta counts within 2% and 4% of each other. By contrast, the two samples from within the formation yielded alpha and beta counts 22% to 45% higher than the averaged controls. In light of our subsequent discovery of short-lived radionuclides in the Beckhampton oval, we think it reasonable to believe that the samples' emissions were not due to normal soil variation.
Our next step was to identify the specific radioactive isotopes responsible for the elevated emissions. Thus we sent the samples to another lab for gamma spectroscopy, which was performed on August 26th. Analysis of the output revealed the presence of thirteen unusual and short-lived radionuclides in the samples. Two were found in all three samples. Eleven were in either 1A or 1B but not in the control. We list these eleven radionuclides in Table 1.
(An explanatory note: the number following each isotope's name indicates its atomic weight, i.e. the combined number of protons and neutrons in the nucleus. It is necessary to specify the atomic weight to distinguish different isotopes of the same element from each other. For example, uranium-235 and uranium-238 are different isotopes of uranium, and have different nuclear properties, though they remain chemically identical. Most elements have many isotopes, some of which are common and long-lived, some of which are rare and short-lived. The ones listed in Table 1 fall in the latter category.)
Table 1. Radionuclides in Samples 1A and 1B But Not In The Control
Radionuclide Abbrev. Present in 1A Present in 1B Half-life Lead-203 Pb-203 Probably* No 12.17 days Europium- 146 Eu-146 Yes No 14.6 days Tellurium-119m Te-119m Yes No 4.7 days Iodine-126 I-126 Yes No 13.02 days Bismuth-205 Bi-205 Yes No 15.31 days Vanadium-48 V- 48 Probably No 16.1 days Protactinium- 230 Pa-230 Yes Yes 17.4 days Ytterbium-169 Yb-169 Yes No 32 days Yttrium-88 Y-88 Yes Probably 106.6 days Rhodium-102 Rh- 102 Yes No 2.9 days Rhodium- 102m Rh-102m** Probably No 207 days
* "Probably" indicates identification somewhat short of certainty, due to low activity.
** "m" means "metastable." Rh-102m has the same number of protons and neutrons as Rh-102, but its nucleus has a different physical configuration. The two isotopes have different half- lives but, for our practical purposes, the same ancestors and decay products. We thus treat them as a single isotope.
It is of crucial importance that none of the radionuclides in Table 1 appeared to be in the control, since it helps rule out many mundane explanations. The control did have long-lived, naturally occurring radionuclides such as uranium-238 and radium-226, and long-lived artificial radionuclides from Chernobyl such as cesium-137. But all three samples contained these radionuclides, unsurprisingly.
But the presence of the short-lived radionuclides is surprising. To understand why, the reader should consider their halflives (see Table 1.) "Half-life" refers to the amount of time it takes for half of a given amount of an element to decay into some other substance. For example, it would take 17.4 days for half of a given amount of protactinium-230 to decay. After twice that time, only 25% of the original amount would be left, and so on. Therefore, any amount of protactinium-230 will diminish to undetectable levels in a matter of weeks. By contrast, naturally occurring uranium-238 has a half-life of over four and a half billion years. It thus can be naturally occurring whereas Pa-230 cannot be. Should scientists want to study short-lived isotopes, they must synthesize them in cyclotrons or experimental nuclear reactors; they can't just refine them from soil or ores. Finding them in apparently ordinary soil from rural England is almost as surprising as finding cut diamonds would be. It is radically out of line with normal expectations.
Before going on with our discussion, we want to reassure readers that the presence of the short-lived isotopes does not appear to present any health threat. Even though the samples emitted higher percentages of radiation than the control, their total emissions were far below the danger threshold. This is because the radionuclides were present in such low concentrations that they could only be detected by exquisitely sensitive equipment. The absolute quantities of the radionuclides were so low that one would probably be exposed to more radioactivity by eating a banana (which contains the natural radionuclide potassium-40) than by spending 24 hours in a fairly new crop circle.
Readers should also consider the fact that none of the leading researchers of the phenomenon have contracted cancer or other radiation-induced illnesses, despite having spent many hundreds of hours in crop circles over a decade of study. Not only that, it is far from clear that radiation anomalies are a general property of crop circles. Of the six we examined for elevated alpha/beta emissions, only two exhibited significant increases. Two others exhibited apparently significantly lower emissions, and the last two exhibited no significant differences.  Research in 1992 could reveal that only a certain percentage of apparently genuine crop circles exhibit radiation anomalies at all. This would further reduce cause for concern.
To return to our discussion, where could the radionuclides have come from? Let us first consider (and reject) eight mundane explanations. Actually, the absence of the radionuclides in the controls automatically rules out most of these explanations, but for thoroughness's sake, we will consider them anyway.
Thus we have ruled out natural radionuclides, cosmogenic radionuclides, sample jar contamination, atmospheric nuclear tests, Chernobyl, airport X-ray detectors, TNA detectors, and contamination with hospital waste by hoaxers. We must now consider some less mundane possibilities.
II. The Origin of the Radionuclides
Broadly speaking, there are two ways the radionuclides could have got into the ground. One way is contamination, which would consist of pouring or spraying a solution or dust containing the radionuclides onto the ground. We think contamination unlikely for the same reasons a hoax is unlikely: the difficulty of making the radionuclides prior to placing them in the area, and the almost equal difficulty of applying the contaminated material over a large but sharply delimited area.
The other way is activation. Activation is the process of bombarding atomic nuclei with energetic subatomic particles. The nuclei capture the particles and are thus transformed into different nuclei. If the number of neutrons in the nuclei change, they become different isotopes of the same element. If the number of protons change, they become different elements altogether. For example, it is theoretically possible to change lead into gold by activating it with the right mixture of particles. The only obstacle, aside from its difficulty, is the fact that it would cost more than an ounce of gold to produce an ounce of gold.
There are many different kinds of activation: activation by alpha particles, activation by protons, activation by deuterons, and so on. Each kind will have different effects on a given atomic nucleus. But despite this complexity, activation enables us to produce an elegant hypothesis about what happened to the soil. We have discovered that the radionuclides in Table 1 have one and only one common denominator, and that is activation of naturally occurring elements with deuterium nuclei (deuterons.) In a moment we shall undertake to prove this, but first it may be helpful to explain just what deuterium nuclei are and what they can do.
Deuterium is an isotope of hydrogen. Its nucleus is composed of a proton and a neutron. (The rest of the atom consists of an electron, which is easily stripped off to leave the ionized, bare nucleus.) Since ordinary hydrogen's nucleus contains only a proton, deuterium's extra neutron entitles it to be called "heavy hydrogen." Deuterium is not a particularly rare isotope, since it exists in small quantities in ordinary water. It is a useful one, however, since it is used to control neutron emissions in fission reactors, and constitutes much of the fuel in fusion reactors. Of course, knowing these basic facts still tells us nothing about where these deuterium nuclei (we shall henceforth use the term "deuterons") came from. They could have come from any number of sources, including ones not yet known. At the moment, we think it more useful simply to assert that they existed than to speculate about their origin.
In any case, the deuterons we hypothesize are remarkable not because they are rare, for they are not, but because they are highly energetic. Most deuterium particles found in nature are relatively unenergetic, such as the ones in ordinary water. An unenergetic, that is, a slow-moving, deuteron cannot penetrate and alter atomic nuclei, just as a bullet casually tossed at a television set will not penetrate it. An energetic deuteron is a different story. A deuteron accelerated to high speeds can penetrate an atomic nucleus and "activate" it, i.e. convert it into a different isotope or even a different element. Like a bullet fired from a gun, it can radically alter the objects it strikes. But the energies would have to be large. We think that to activate atomic nuclei, deuterons would have to possess energies exceeding one mega-electron-volt (MeV). That means, roughly speaking, that each deuteron would have to be accelerated by an electrical field possessing a total potential of not less than one million volts, which is a considerable amount of energy.
In this paper, we make no real attempt to figure out what could have generated energies of that scale, nor do we analyze whether such energies could arise naturally on planetary surfaces. For the moment, our goal is only to convince readers that the energies existed. To do that, we need to show that deuteron activation is indeed the most plausible route of production of the radionuclides in Table 1. For if deuterons that energetic existed, then so did the energies. We will do this by accounting for each radionuclide in terms of deuteron activation. The following discussion will be fairly long and technical, but we think it necessary to defend our thesis in some detail, since it is so unusual and surprising. The nontechnical reader can skim the discussion without trying to understand all of its details; the important thing to understand is that we are showing that all the radionuclides very likely came from a common source. To put it another way, we are showing that there is considerable internal consistency to the data. If we can do this, it will help prove that we have discovered something significant about the actual physical mechanism which created this particular crop circle. To be specific, it appears to have emitted quantities of deuterons, which converted stable isotopes in the soil into unstable, radioactive ones.
We shall forthwith account for each radionuclide in terms of deuteron activation. Let us start with the easiest four to explain, protactinium-230, iodine-126, rhodium-102, and rhodium-102m. These four radionuclides have one thing in common: they can only be made by activation. (To say the same thing another way, none are ever generated by radioactive decay.) What atoms could have been activated to make them, then? There are several possibilities for each radionuclide (see Table 2.) The nontechnical reader should not be intimidated by this table. It simply lists each radionuclide in the first column, and each of its possible atomic parents in the second column, along with what would have had to activate them in parentheses. For example, protactinium-230 can be formed by three different activation reactions: a proton impacting a thorium-232 nucleus, a deuteron impacting a thorium-232 nucleus, or a deuteron impacting a thorium-230 nucleus. 
Table 2. Radionuclides Which Are Not Decay Products, And Possible Activation Parents For Them
Radionuclide Possible Activation Parents (activating particle in parentheses) Pa-230 Th- 232(proton) Th-232(deuteron) Th-230(deuteron) Rh-102 Ru-101(deuteron) Ru-102(proton) Ru- 102(deuteron) Rh-102m Pd- 104(deuteron) Rh-103(neutron) Rh-103(deuteron) Rh- 103(gamma) I-126 Sb-123(alpha) Te- 125(deuteron) Te-126(deuteron) I-127(gamma)
Note that all four radionuclides have one, and only one, common denominator: deuteron activation. While this does not rule out the other kinds of activation, it does allow the hypothesis that only one kind was involved. Let us therefore focus on the parents which can be deuteron-activated. Table 3 is Table 2 with the non-deuteronactivated parents left out. It also asks an important question: are the remaining possible parents naturally occurring? In fact all of them are, which significantly enhances our hypothesis.
Table 3. Hypothesized Activation Parents Of Pa-230, Rh-102, Rh-102m, and I-126, Assuming Deuteron Activation
(% of All Naturally Occurring Element
Pa-230 Th-232 Yes (100%) Th-230 Yes (decay product of U-234; extremely rare) Rh- 102 Ru-101 Yes (17.1%) Rh-102m Ru- 102 Yes (31.6%) Pd-104 Yes (11.0%) Rh-103 (100.0%) I-126 Te- 125 Yes (7.0%) Te-126 Yes (18.7%)
The percentages denote how much of that element is constituted by that particular isotope. Most naturally elements are composed of more than one isotope of that element.
Now let us consider another two radionuclides from Table 1, yttrium-88 and europium-146. These are more complicated cases because
they could have been made by decay or activation. Let us first consider the possibility of decay. Yttrium- 88 has one decay parent, zirconium-88. Zirconium-88 has a half-life of 83.4 days, which means that some of it should have been left in the sample if it was the source of the yttrium-88. However, the gamma spectroscope detected no zirconium-88; we can thus rule out decay. Something must have been activated, then, and there is only one candidate: strontium-88 (82.6% of all naturally occurring strontium.) Strontium-88 can be made into yttrium-88 either by deuteron or proton activation. We infer the common denominator of deuteron activation.
The europium-146 presents a case like yttrium-88's. One of its decay parents, gadolinum-146 (half-life: 4.6 days) was not found in the sample. Its other decay parent is terbium-150, but since only .05% of it decays into europium-146, a fairly large amount of this rare element would have had to be present in order to be converted into detectable quantities of Eu-146. Activation is again the more likely possibility. It turns out that europium-146 can be made by proton activation of samarium-147 (15.1% of all naturally occurring samarium), or by deuteron activation of samarium-144 (3.1%.)  Our reasoning is summed up in Table 4:
Table 4. Radionuclides with Parents Not Present, And Activation Possibilities
Radionuclide Decay Parents Activation Parents Deuteron-Activated
Y-88 Zr-88 (none) Sr-88(proton)
Yes (82.6%) Eu-146 Gd-146 (none) Tb-150
(only 0.05% decays into
Eu-146, hence unlikely)
Let us move on to consider five more of Table 1's radionuclides, namely bismuth-205, vanadium-48, tellurium-119m, ytterbium-169, and lead-203. These have more than one possible decay parent. None of these possible decay parents were detected, however. There are two reasons for this. One is that most of the decay parents have such short half-lives that they would not have been detectable by the time the samples were counted. The other is that there probably were never any of those decay ancestors in the sample to begin with, for all of the radionuclides can be much more easily accounted for by activation.
Consider the bismuth-205 first. It has two possible decay parents, astatine-209 (half-life: 5.41 hours) and polonium-205 (half-life: 1.8 hours.) Since 99.86% of polonium-205 decays into bismuth-205 whereas only 4.1% of astatine-209 does, the polonium is the more probable decay parent. But polonium-205 is still not a very probable parent, partly because it cannot be made by deuteron activation, and partly because its parents can only be made by activation methods which are far more exotic than the kinds we have been discussing. On the other hand, bismuth-205 can be made by deuteron activation of lead-206, which constitutes 25% of all naturally occurring lead. Thus deuteron bombardment of the soil almost certainly would have produced some bismuth-205.
Take the vanadium-48 next. Its only decay parent is chromium-48 (half-life: 21.56 hours), but it cannot be made by deuteron activation. On the other hand, vanadium-48 can be made by deuteron activation of titanium-48 or chromium-50. The former constitutes 73.7% of all naturally occurring titanium, and the latter constitutes 4.35% of all naturally occurring chromium.
To keep this paper from growing too tedious, we will not discuss the tellurium-119m, the ytterbium-169, and the lead-203. However, our reasoning for them is similar to the two radionuclides just discussed above, and is summed up along with them in Table 5.
Table 5. Radionuclides with Short-Lived (And Not Present) Decay Parents, And Activation Possibilities
(NPDA="not producible by deuteron activation")
Radionuclide Decay Parents Activation Parents Deuteron-Activated
Bi-205 Po-205(NPDA) Pb-206(deuteron) Yes (25%) At-209(NPDA) V-48 Cr-48(NPDA) Ti-48(deuteron) Yes (73.7%) Cr-50(deuteron) Yes (4.35%) Sc-45(alpha) Ti-48(proton) Te-119m I-119(NPDA) Sb-121(deuteron) Yes (57.3%) Sb-121(proton) Sn-116(alpha) Yb-169 Lu-169(NPDA) Tm-169(deuteron) Yes (100%) Yb-168(neutron) Pb-203 Bi-203(NPDA) Tl-203(deuteron) Yes (29.5%)
This concludes our discussion of the 11 radionuclides of Table 1. We sum up our analysis in Table 6, which shows how we accounted for the radionuclides as producible by deuteron activation of naturally occurring stable elements in the soil.
Table 6. Summary. Most Likely Parents of the Radionuclides in Table 1 (Assuming Deuteron Activation)
Radionuclide Present in Control? Believed Activation
Are Activation Parent(s)
Lead-203 No Tl- 203 Yes Europium-146 No Sm- 144 Yes Tellurium-119m No Sb-121 Yes Iodine-126 No Te-125, Te- 126 Yes Bismuth-205 No Pb-206 Yes Vanadium-48 No Ti-48, Cr- 50 Yes Protactinium-230 No Th-230, Th-232 Yes Ytterbium-169 No Tm-169 Yes Yttrium-88 No Sr-88 Yes Rhodium-102 No Ru-101, Ru-102 Yes Rhodium-102m Probably Yes
Our analysis was not quite exhaustive. We cut through a maze of isotopic parents in the belief that the simplest solution was the most likely to be correct. We could be wrong: some of these radionuclides could theoretically be end-products of a cascade of decayings of extremely exotic and short-lived isotopes. Or proton activation could have produced some of the radionuclides while deuteron activation produced the others. But we think these possibilities unlikely. The former requires much greater complexity to arrive at the same result; the latter would probably have produced radionuclides which could only be made by proton activation, yet we have found none.
III. Loose Ends
No item of exploratory scientific research can answer all questions and settle all difficulties. Ours is no exception. Let us discuss what loose ends need to be cleared up with further research. (Nontechnical readers may wish to skip this section, since it is not central to our analysis.) The first loose end is the existence of two unusual radionuclides in all three samples, including the control. They are listed in Table 7.
Table 7. Radionuclides Present in 1A, 1B, And The Control
Radionuclide Present in 1A?. Present in 1B? Present in Control? Half-life Gold-194 Yes Yes Yes 1.65 Days Thallium-202 Yes Yes Yes 12.2 Days
The gold-194 is puzzling, since it has such a short half-life - less than two days. Either enormous quantities of it were initially present when the samples were collected, in which case the field would have been extremely radioactive, or something long-lived is continuously generating it by decay. The latter seems the likelier case. Gold-194 can be generated by the decay of mercury-194, which has a half-life of 520 years. The mercury-194 could have been created by a two-step activation process, whereupon the deuterons activated platinum-194 (32.9% of all natural platinum) to create gold-194, which was itself activated to make the mercury-194. The deuteron stream would have to last long enough, and be intense enough, to activate isotopes which had just been created by that same stream.
Assuming this is plausible, how do we explain the presence of the gold-194 in the control? Consider the fact that the mercury-194 has a half-life of 520 years. If the field had had crop circles in earlier years, the mercury-194 could have been spread around the field by wind, erosion, and plowing.
There are other possibilities, of course: the Chernobyl tables could be incomplete, or a nearby reactor might have emitted some mercury-194. Further research is needed to clear up the question.
Our analysis is similar for the other radionuclide, thallium-202.
The second loose end is why none of the hypothesized parents are abundant elements. If trace elements like titanium and samarium were activated, it seems that abundant elements like silicon and oxygen should have been also. To answer this question, we took each element which composes more than 1% of the earth's crust and found its most likely deuteron-activation products. It turns out that they are either stable, in which case they would not have been detected by our instruments, or they have such short half- lives that they would have decayed off before testing, as Table 8 shows.
Table 8. Most Likely Deuteron Activation Products of Elements Which Compose More Than 1% Of The Earth's Crust
Element Abundance in Crust Most Likely Product Product's Half-Life Oxygen-16 46.6% Flourine-17 1.075 minutes Silicon-28 27.72% Phosphorus-29 2.5 minutes Aluminum-27 8.13% Silicon-29 Stable Iron-56 5% Cobalt-58 9.15 hours Calcium-40 3.63% Scandium-42 1.027 minutes Sodium-23 2.83% Magnesium-25 Stable Potassium-39 2.59% Calcium-41 Stable* Magnesium-24 2.09% Aluminum-26 6.3 seconds
* Calcium-41 has a half-life of 1.03 x 10 to the 5th years. It is thus not truly stable. But it does not emit gamma rays, so it would not have been detected by our instruments.
The iron-56 deserves further scrutiny. Deuteron activation of iron-56 can also produce the radionuclides manganese-54 (half-life: 312 days) and cobalt-57 (half-life: 72 days.) But these would require levels of energy perhaps higher than required to generate most of the observed radionuclides. Our data did show peaks in the region of manganese-54, but not at sufficient resolution to permit positive identification. Clearly, in 1992 we will have to look carefully for activation products of the soil's abundant elements. Prompt testing will greatly facilitate the search.
Table 8 shows something else: the soil could well be dangerously radioactive for a short time after the formation is made. Since elements like silicon and oxygen (which exists as oxides bound up in the soil) are so abundant, their activation products would also be abundant. They would emit a large aggregate quantity of radiation, albeit for only a few minutes or hours. Out of simple prudence, then, fulltime researchers who enter a crop circle the morning after it is made should carry a sensitive survey meter (a Geiger counter is one kind of survey meter, though we would use other kinds) or an electrostatic film badge. Given the low amounts of radiation we think we are dealing with, these tools will have to be highly sensitive, and their users will have to be well trained; anything less would risk yielding nothing but false negatives. These instruments should reveal no cause for alarm, but if they do, we shall adopt more cautious sampling procedures.
Additional loose ends derive from the fact that the size of our sample set is too small to show that short- lived radionuclides are part and parcel of the crop circle phenomenon. However, we think our findings are so suggestive that further research is emphatically warranted. If one takes a single bucket of rock from a mine and finds gold in it, one is well justified in doing further digging.
We also need to take more controls in 1992. For this paper, two or three would have been better than one. Even so, the radionuclides are so unusual that finding them anywhere is cause for interest. The difference between our samples and single control is qualitative in an absolute, not a statistical, sense. The case would warrant further investigation even without a control.
In addition, our interpretation of the data from the gamma spectrometer needs to be confirmed by similar findings from independent laboratories. Spectroscopic data is extremely complex, and its interpretation is inevitably a matter of judgment. But our interpretation of the data has convinced several of our associates in Oak Ridge. We believe it will stand; and we would be glad to show the raw data to those who wish to examine it for themselves.
IV. Where Might The Deuterons Have Come From?
So far, our hypothesis of a stream of deuterons suggests a possible physical concomitant of whatever flattens the plants, but it provides almost no clues as to the actual cause of the phenomenon.
We can only speculate on several possibilities.
One possible cause is the naturally occurring "plasma vortex" hypothesized by some meteorologists.  The question is: is this hypothetical (and never experimentally detected) plasma vortex theoretically capable of generating the requisite number and density of deuterons? Obviously, this is a question requiring very detailed analysis, which we lack the expertise to perform. While we doubt that the lower atmosphere can naturally generate deuterons with energies sufficient to activate atomic nuclei, the possibility cannot be ignored.
If our research in 1992 demonstrates the presence of short-lived radionuclides in many crop circles, the meteorologists will have the burden of proving that their hypothesized plasma vortex can produce them. Also, since the radionuclides have appeared in at least one complex formation, the meteorologists would have the additional burden of proving that their plasma vortices can produce such shapes. So far, they have proven neither assertion. In fact, they have given up on the latter one. For example, Terence Meaden has recently asserted, "It is obvious that most, perhaps all, complex sets of circles seen in Britain in recent years have been made byhoaxers."  Our data suggests otherwise.
The only other cause we can think of is a deliberately directed stream of deuterons. It would be worthwhile to calculate the energy required for such a stream, given the radionuclides observed, their concentration, and the size of the area in which they are found. The ballpark figures might help us evaluate theories of intentional manufacture.
However, hypothesizing a stream of deuterons still does not explain how the plants are actually flattened. The deuterons could not exert enough force to press the plants to the ground, for if they did, the plants would also be burned to a crisp. However, perhaps they heat the plants to some extent. Since it appears from W.C. Levengood's observations of plant cells that the plants are strongly but briefly heated, it might be possible to compare calculations of the heat experienced by the plants with the heat theoretically generated by the deuteron stream.  Perhaps the deuterons heat the plants just enough to make them pliable, while some other force bends them to the ground in the intricate patterns often observed.  Or perhaps the deuterons are not directly necessary to the flattening process at all, but are merely a concomitant of the overall physical process.
Our results point suggestively toward some radioactive source which exposes the soil to a stream of energetic deuterium nuclei. To test this hypothesis, we hope to perform these same tests on multiple crop circles next summer. 1992's radiological research program should include the following aspects:
The authors wish to thank the following people for their help and advice: Kevin Folta, Tsahi Gozani, Conrad Knight, Jurgen Kronig, W.C. Levengood, David Chioni Moore, Chris Rutkowski, Dennis Stacy, and George Wingfield. The secondary author's fieldwork in England was supported by a grant from the Fund for UFO Research.
Captions (Photo not included in file)
Photo 1. The "fish" or "long oval" formation near Beckhampton. According to John F. Langrish, it was formed on July 31 / August 1, 1991, at SU 0865 6810. Photo courtesy of Jurgen Kronig.
 According to John Langrish, the Beckhampton oval's location was SU 0865 6810. (Eight-figure Ordnance survey references are accurate to 10 meters.) The date given in the text differs from the one given in a preproduction version of Michael Chorost's report, The Summer 1991 Crop Circles (Fund for UFO Research, in press.) The change was made due to more authoritative data supplied by Langrish.
 Variations above 10% were considered significant. The data and statistics may be obtained from the secondary author at North American Circle, P.O. Box 61144, Durham, North Carolina, 27715-1144 USA.
 The six cases are discussed at length in The Summer 1991 Crop Circles: The Data Emerges (Fund for UFO Research, Mt. Rainier, MD, in press.) A condensed version of the report was printed in the Mufon UFO Journal, October 1991, pp. 3-15.
 The inventory of Chernobyl emissions is in "Cleanup of Large Areas Contaminated As A Result Of A Nuclear Accident," Technical Reports Series no. 300, International Atomic Energy Agency, Vienna, 1989, p. 104. The inventory of widely distributed human-made radonuclides is in Environmental Radiation Measurements, National Council on Radiation Protection and Measurements Report no. 50, Washington, D.C., 1976, pp. 12-14.
 "Environmental Radiation Measurements" (see note 4), 11.
 We checked these facts with the primary designer of the device, Dr. Tsahi Gozani of SAIC in California.
 We checked these facts with Conrad Knight, a Radiation Safety officer at Duke University Medical Center.
 All of the decay/activation parents and products cited were obtained from Edgardo Browne and Richard B. Firestone's "Table of Radioactive Isotopes." New York: John Wiley and Sons, 1986.
 The Browne and Firestone reference does not show a deuteron activation which yields Eu-146, but another reference, the Gerhard Erdtmann one, does. We believe that one is accurate, because Eu-146 should be producible from a Sm-144 (d, nothing) reaction. Again, we infer deuteron activation. (Gerhard Erdtmann, "The Gamma Rays of the Radonuclides: Tables for Applied Gamma-Ray Spectrometry." New York: Verlag Chemie, 1979.)
 See, for example, "Circles From the Sky", ed. Terence Meaden. Souvenir Press, 1991.
 "Analysis and Interpretation of the Luminous-Tube Phenomenon." Terence Meaden. Journal of Meteorology v. 16 no. 162 (October 1991): 276-278.
 See Chorost, The Summer 1991 Crop Circles, Section IIIB (see note 3.)
 See, for example, Stanley Morcom's "Field Work: The Pictogram at East/West Kennett Long Barrows." The Circular vol 2 no. 1 (March 1991): 10-13. Also Circular Evidence (Delgado and Andrews, Bloomsbury, 1989), pp. 121-131, and Circles From The Sky, pp. 46, 153-158.