Memoirs of the ISU Radiation Laboratory 1970-1996

1. Memoirs of the ISU Radiation Laboratory 1970-1996 Director: John Swez Special Thanks to: James Teegarden, Dale Manwaring, Adron Barbee, Bob Kujawa, Greg Peterson, Randy Hecklesburg, Keith Grimm, Paul Mason, Tonya Balch

2. Inside the “Cobalt Cave” Director John Swez, May 1971 - 1996 The ISU Radiation Laboratory started about 1967 and was designed by Dr. Clyde Parrish then of the Department of Chemistry. It ended in 1996. Dr. Parrish resigned in 1971. Robot Manipulators (“Waldo’s”) The interior of the cave area. The iron impregnated concrete walls are 5 foot thick to absorb the cobalt gamma radiation “pit “ area. The pit is 2 ft wide x 26 ft depth

3. One of the eight Cobalt Rods1 Specially designed holder for a total of eight rods The “Elevator” The maximum amount of the radioactivity that was in the Cobalt Cave was 11,000 Curies A Curie is 3.7 x 1010 dps. It has been replaced by a newer unit called a becquerel 1This rod approx. 12 inches long is a “fake rod” with serial number AECL 00

4. Decay Scheme for Cobalt-60 Half Life of 27Co60 = 5.2714 years The transformation constant is: Half life = 0.693/  =4.1687 x 10-9s-1 Beta Particle 1 Bq = 1 tps Gamma Rays 1 Curie = 3.7 x 1010 Bq At its peak the ISU Radiation Lab housed 11,000 Curies

5. Location of Cobalt on the Periodic Table

6. Gamma Rays: Definition “Gamma Rays are monochromatic electromagnetic radiations that are emitted from nuclei of excited atoms following radioactive transformation; they provide a mechanism for ridding excited nuclei of excitation energy” 1 Gamma Rays are very penetrating Energies are measured usually in MeV Xray Energies (by comparison) are measured in KeV (but Xrays are indistinguishable from Gamma Rays) An eV is a unit of energy (an electron volt) 1.6 x 10-19 Joule = 1 eV = 1 electron volt The ionization potential of a hydrogen atom is 13.6 eV 1Introduction to Health Physics, 2nd Edition by Herman Cember, Pergamon Press 1983: ISBN 0-08-030129-0

7. What is the difference between the energy of a Co60 gamma ray (1.332 MeV) and the ionization energy of Hydrogen, a 40 meter electromagnetic wave, a 70 cm electromagnetic wave, green light and a microwave oven? Ans: It is related to Planck’s Constant by E = h  Type of Wave Wavelength (m)  (Hz) Energy (eV) Green light 540 x 10-9 5.6 x 1014 2.3 Microwaves 2450 MHz 0.00001 70 cm Band 0.7 4.29 x 108 1.77 x 10-6 40 meter Band 40 7.5 x 106 3.1 x 10-8 Ionization Energy (H) 13.6

8. How many grams of Co60 did the Radiation Lab have? Answer:

9. Vertical Side View of the Cobalt “Cave”

10. The “Elevator” was fabricated from stainless steel and was approximately 20 inches tall. (Most parts were made from austenitic stainless steel) Cables which were connected to an elevator/motor system. Lead shielding bricks. The eight cobalt rods were temporarily housed in a small pit underneath while maintenance to the elevator was performed

11. A view of the 26 foot “pit” or “well” as we referred to it. The well was mostly filled with de-ionized water. When the elevator (and Cobalt rods) were lowered to the bottom of the pit the water acted as a shield for the cobalt gamma radiation. The radiation level at the top of the water was near background. The “pit” is shown empty here.

12. The “pit” or “well” is shown here full of water. You can see the level of of water in the photo. The elevator is at the bottom of the pit. However, the Cobalt “rods” have not yet been inserted into the rod holders.

13. This is the same picture. Except the rods are now inserted into the elevator carriage holder. The source is at the bottom of the “pit”. You are viewing Cerenkov Radiation.

14. Control Operating Console The only thing not normal to the picture is this camera Typical view of the Radiation Laboratory outside area circa 1980. That is probably me in front of the viewing window operating the “waldo” robot manipulator slaves.

15. How did the Cobalt 60 Rods Arrive at ISU? • Well not just UPS! • Because of the intense radiation levels the rods were shipped in a special “J Type” shipping container of 5000 lb in weight. • They were fabricated at Atomic Energy of Canada • Because of the half-life of Cobalt 60 there were two shipments made between 1968 and 1980. The Cobalt 60 half life is 5.3 years.

16. How the Cobalt Rods arrived 1980 5000 lb lead pig, a special J type shipping container

17. The outside of the Cobalt Cave showing the “Waldo” arm grips and the Zinc-Bromide Viewing Window. Officials of Indiana State University are viewing the cobalt rods through the viewing window. Jim Teegarden is in the background.

18. Viewing through the 250 gallon Zinc Bromide filled window. The radiation level in front of the window was about twice background. You are looking at the stainless steel mirror directly above the source.

19. You are looking through the zinc bromide viewing window at a bucket which is holding the eight cobalt rods. The bucket is supported by a chain hooded to a hydraulic hoist on the ceiling of the “cave”. A polished stainless steel mirror is positioned on the wall above the bucket in the picture. Glass cannot be used because of instant radiation darkening There is a “temporary pit” six feet in depth directly on the floor below. This “temporary pit” will accept this bucket with the rods in the event that work might need to be done on the elevator.

20. What was the ISU Radiation Laboratory used for from 1967 – 1996? • The (then) Naval Weapons Support Center at Crane, Indiana was a major contractor for this period. Monies we received from them we used for graduate assistant salaries. Research with the NWSC involved hardening of electronic devices in the Poseidon and Minuteman Missile Program. • Much biological work in rat systems occurred during this period at ISU. Ionizing radiation (near lethal doses) were used to destroy the immune system of rats and mice. • Many chemicals synthesized by local drug manufacturers would need to be sterilized. Cobalt gamma radiation would do the job well. • Many polymerization systems could be stimulated with “accelerators”. Gamma Radiation also acts as an accelerator. Once, during a test of polymerizing a military flare, the flare detonated. This was not good. • Sometimes outside contractors simply wished to sterilize some glassware or other laboratory materials. • We kept a record of every single irradiation the Rad Lab.

21. Bob Kujawa circa 1982 assisting me in cleaning the pit and elevator. Bob is standing on lead bricks (about 30 lbs each) which have been piled on top of the “temporary pit” to act as shielding. When the “temporary pit” was constructed it was not built with sufficient shielding. To the left of Bob you can see the chain coming from the air hoist on the ceiling of the “cave”. At the bottom left is a standard GM (Geiger Mueller) counter. We never entered the cave area without the GM counter even though the control console would indicate it was safe.

22. Here the elevator has been serviced and the water has been changed. I am carefully pushing the key attached to the chain into the storage pit door. I will then lift the 1000 lb lead door up from the outside using the hoist. The door is attached to the bucket which contains the rods. Later the robot “waldos” will place the rods into the elevator which is to the left

23. The elevator and well “serviced” and ready to receive the rods. After the transfer of the rods a cage would be placed over the assembly to that no damage to the rods might result from an accident or explosion in the cave Note the “up source” relay which would sense when the elevator reached its maximum height

24. The AEC (Atomic Energy Commission) which is now the NRC (Nuclear Regulatory Commission) required warning signs posted around and in the facility.

25. Bob Kujawa and I in one of our humorous moods. Although we dealt with radioactive substance one of the more deadly things known to man, we always kept a joyful but vigilant attitude about our work.

26. Note the “spare” rod holder. Room Alarm The “Control Console” for the Radiation Laboratory played a vital role in the safety of the Radiation Laboratory. Outside or Room area radiation monitor High and Low Level Monitors. That “spare” GM counter. Always there when you are ready to enter the room. Indicator for Room Area Monitor

27. January 28, 1970. Radiation Emergency. A rod had fallen down into the emergency pit. The pit was only 4 inches square. The bucket was not there to catch it. It fell to the bottom of the pit. I had 24 hours to “solve the problem”. After that a call would result to the Nuclear Regulatory Commission (Then the Atomic Energy Commission). Probably a “Tiger Team” would have been sent down to ISU immediately to rectify the problem. Two undergraduate students and one graduate student and I stood in front of the viewing window pondering our problem. One undergraduate student shouted, “Hey Doc, why don’t you just get a magnet and fish it out!”. At first I told the student to keep his nonsensical remarks to himself. Then I realized he was right. Stainless steel is austenitic and slightly magnetic. This picture was a Polaroid taken right after we recovered the rod. “Weak Minds Over Strong Matter” Cobalt 60 is paramagnetic.

28. Repair of the Zinc Bromide Viewing Window, January 1973. Eventually the Zinc Bromide deteriorated in the viewing window. Here Keith Grimm, Randy Hecklesburg and Adron Barbee are with me (back of the window)

29. Characteristics of Concrete with penetration of Cobalt Gamma Rays d1/2 is defined as the thickness necessary to reduce the intensity by 1/2

30. Jim Teegarden inspecting the deterioration of the zinc bromide viewing window after 7 years of radiation damage. The damage resulted from the effect of gamma rays on the paint and the interaction with the liquid zinc bromide. We scraped and repainted the window in 1973 with a good marine grade of epoxy paint. However, we ran into a big problem. The only zinc bromide we could find marketable in the world was from Great Britain, who after we ordered it decided that their supply of zinc bromide was too critical to their nation’s welfare and delayed shipment for two years. Our solution was to fill the window with plain water. The water was an insufficient radiation shield so we had to fabricate a brick wall in front of the window (temporarily).

31. Radiation Dosimetry Basics • Roentgen – defined s that quantity of X or gamma radiation that produces ions carrying one statcoulomb of charge of either sign per cubic centimeter of air at STP 1 R = 1 SC/cm3 • 1 ion carries a charge of 4.8 x 10-10 SC • The mass of 1 cc3 standard air is 0.001203 g • An exposure of 1 R = 87.7 ergs per gram of air • 1 R therefore equals a dose to air of 0.877 rad • Average energy in a single ion pair (air) = 34 eV

32. Roentgens Exposure Therefore for 11,000 Curies at one meter the exposure is 14520 R/hr (242 R/min) Note: we have assumed a point source so this is very approximate. This value was verified with chemical dosimetry (ferrous sulfate dosimetry)

33. TV monitor hooked to camera in “cave” Remote slave manipulator J type shipping container. The delay in waiting for zinc bromide would be two years. In the meanwhile we had a “change of rods” schedule with AECL of Canada in 1980. So after we built a lead brick wall in front of the viewing window which was filled with distilled water, we operated with TV cameras. Unfortunately because of the intense gamma radiation the lenses to TV cameras became dark and un-operable.

34. Jim Tegarden (left) and Keith Grimm (right) inspecting the new Zinc Bromide viewing window. Picture is taken from the entrance door to the outside of the radiation laboratory. The door to the “cave area” can be just seen to the left of the blackboard in the back of the picture. This picture affords an excellent view of the robot slave manipulators (waldo’s) in the upper center of the photo. In 1967 their cost was $68,000.

35. Meaning of the term “goosed” Source: The Free Dictionary by Farlex

36. One of our major concerns was leakage of the deadly Cobalt 60 from the sealed rods themselves into the surrounding water of the “pit”. This would result in possible transfer of deadly radiation to the outside world. Especially, when it came time to change the water in the pit and discharge it into the Terre Haute sewer system. This might be a very unhappy scenario. I built a special 3 inch sodium iodide detector which was sensitive to within 10 pico-curies of Cobalt radioactive material. In this notebook we kept all the leak test records of the ISU Radiation Laboratory. This is what we are looking for. The two Co60 Gamma Peaks at 1.17 and 1.33 MeV