E/EC REPORT
PIONEERS IN PROPELLANTS The Jet Propulsion L a b o r a t o r y has been engaged in the development of solid and liquid propellants for use in rocket and guided missile propulsion systems for the past 1 7 years. Pioneering achievements in both these fields have led to important contributions to the nation's guided missile program. The propellant field offers a wide variety of problems to the chemist and chemical engineer. The search for new propellants, the stabilization and synthesis of high energy m a t e r i a l s and the control
of
physical properties and combustion
handicaps in radiation processing. Although higher energy machines are now being developed, the average size in use today is 2 m.e.v., which penetrates about 0.4 inch into material of unit density. Commercially practical machines with higher voltages are essential for m a n y uses, since electron penetration is proportional to voltage. An answer to deeper penetration m a y be found in the microwave accelerator—a machine that utilizes high frequency microwaves to accelerate electrons. Insulation problems limit the practical voltage of V a n de Graaff a n d resonant transformer accelerators to about 4 m.e.v. Microwave accelerators can go m u c h higher. H i g h Voltage has standard models designed for 5 a n d 10 m.e.v., and has one machine in operation at over 50 m.e.v. But voltage isn't everything. Microwave accelerators are expensive, and require a proportionately larger power input to obtain unusually high energies.
demand talents in physical, organic, inorganic and analytical chemistry. Special emphasis is placed on combustion, polymers, synthesis, f r e e radical studies and kinetics. The chemical engineer, a t J PL, finds an unusually broad scope for
Cost of Radiation Processing
W h a t ' s the cost? Radiation processing is probably more of an engineering development t h a n a commercial reality. This makes it difficult to list specific figures on cost.
applying his knowledge of thermodynamics, heat and mass transfer, fluid flow and general processing techniques. If y o u a r e i n t e r e s t e d , a
U.S.
citizen, and qualified to work
in
these fields at this well established center of research a n d d e v e l o p ment, send your resume now for immediate consideration.
Job Opportunities Now Open... PHYSICAL CHEMIST · METALLURGIST CHEMICAL ENGINEER PHYSICIST · CHEMIST
JET PROPULSION LABORATORY A Division of C a l i f o r n i a I n s t i t u t e of T e c h n o l o g y
PASADENA • CALIFORNIA A CENTER OF G U I D E D M I S S I L E RESEARCH AND D E V E L O P M E N T
4TH DIMENSION: 2-m.e.v. Van de G r a a f f accelerator installed at Standa r d Telecommunication Laboratories, Ltd., London England
Circle No. 38 A on Readers' Service Card, page 129 A 38 A
FINAL ADJUSTMENTS on the 2 m.-volt Electron Beam Generator are being made in the Coolidge Laboratory opera t e d b y General Electric X-Ray in conjunction with its plant at Milwaukee, Wis. Unit shown is being r e a d i e d for installation at a major chemical company
INDUSTRIAL AND ENGINEERING CHEMISTRY
However, a rough approximation can be m a d e . GE's 2-m.e.v. generator sells for about $120,000, not including installation. Basing amortization on a 5-year period, and adding the estimated cost of installation, operation, maintenance, overhead, etc., the total expense of using the machine comes to the neighborhood of $30 per hour. This particular accelerator is rated at 12 kw. Theoretically, 1 kw. of o u t p u t can irradiate a b o u t 950 pounds of product per hour with a dose of 1 m e g a r e p . Assuming that the beam efficiency will be around 5 0 % , 6000 megarep-pounds can be processed for $30. If a treatment of 10 megarcps is needed (an average dose for irradiation of plastics), then 600 pounds per hour can be turned out at a radiation cost of 5 cents per pound. T h e cost of radiation processing is a direct function of the dose required. Preservation of foods and sterilization of drugs can be accomplished with relatively light treatment—in the range of 1 or 2 megareps. O n the other hand, some tough crosslinking jobs require u p to 100 megareps. Polyethylene-coated wire is one
