Abstract: The microbial life and color life of fresh meat products are extended by placing fresh meat in a tray, sealing the fresh meat in the tray in an atmosphere that excludes oxygen and contains carbon monoxide, and applying ionizing radiation to the tray containing the fresh meat. The color life of the fresh meat in the tray may be controlled (such as to be equal to or less than the microbial life) by employing a permeable element and an impermeable element to seal the fresh meat in the tray. The impermeable element is removed at a time after ionizing radiation has been applied, so that the atmosphere that excludes oxygen and contains carbon monoxide is exchanged for ambient atmosphere, resulting in predictable limiting of color life of the fresh meat.

Abstract: A method of providing extended shelf life fresh meat products involves irradiating the meat products in a first controlled atmosphere and packaging the irradiated meat products in a second controlled atmosphere. The packaged irradiated meat products are then distributed to a retail store. In an exemplary embodiment, the first controlled atmosphere excludes oxygen and the second controlled atmosphere is high in oxygen. In one particular embodiment of the present invention, an antioxidant is added to the meat products either prior to or following the step of irradiating the meat products in the first controlled atmosphere, to extend the color-life of the meat products.

Abstract: A bulk material irradiation system includes an input for inserting bulk material. A bulk material tube is connected to the input, forming a path for bulk material flow. A pressurizing assembly is connected to the bulk material tube for forcing the bulk material to flow through the bulk material tube. An irradiation assembly provides ionizing radiation to irradiate the bulk material passing adjacent to the irradiation assembly in the bulk material tube. Irradiated bulk material exits the bulk material tube through an output.

Abstract: Articles are irradiated by positioning an article to be irradiated in a processing area, controlling an atmosphere in the processing area to exclude oxygen, and applying radiation to the article in the processing area. In one embodiment, the article is positioned in the processing area by conveying the article on a top surface of a product conveyor in the processing area. One exemplary article for irradiation is a tray of fresh ground meat. The tray of fresh ground meat that is positioned in the processing area for irradiation may itself exclude oxygen as well.

Abstract: An irradiation assembly is effective to irradiate large articles, up to about 48 inches thick in an exemplary embodiment. The assembly provides radiation to an article from all sides in a 360 degree exposure range, and includes at least one irradiating subsystem that provides x-ray radiation in a portion of the 360 degree exposure range. A conveying system carries the article through the at least one irradiating subsystem in a number of passes appropriate to provide x-ray radiation to the article in the full 360 degree exposure range. Each irradiating subsystem is configured to direct radiation toward a center point of the article being irradiated. An accelerator generates an electron beam, and a magnet assembly shapes and deflects the electron beam in a sweep path through a scan horn. A compound bending magnet directs the electron beam toward a center point of the article being irradiated along the entire sweep path. An x-ray conversion plate converts the electron beam into an x-ray radiation beam.

Abstract: An irradiation system includes a conveying system for moving material to be irradiated through a processing area. An irradiation source applies radiation to material in the processing area. The conveying system is enclosed by a sealed conduit in at least the processing area, providing the capability to control the atmosphere inside the sealed conduit and to clean the interior of the sealed conduit according to industrial sanitation methods.

Abstract: An electron beam accelerator system includes a high voltage supply circuit having a high voltage output. A cathode structure is coupled to the high voltage supply circuit at the high voltage output. An anode structure is spaced from the cathode structure and has a voltage associated therewith such that a voltage difference exists between the cathode structure and the anode structure. This voltage difference creates an electron beam flowing between the cathode structure and the anode structure. An electron beam output is adjacent to the anode structure. A control grid is located between the cathode structure and the anode structure and receives a time-varying voltage. This time-varying voltage prevents ringing of the high voltage output, reducing the risk of dielectric breakdown and failure due to transient high voltages.

Abstract: A method of providing extended shelf life fresh meat products involves irradiating the meat products in a first controlled atmosphere and packaging the irradiated meat products in a second controlled atmosphere. The packaged irradiated meat products are then distributed to a retail store. In an exemplary embodiment, the first controlled atmosphere excludes oxygen and the second controlled atmosphere is high in oxygen. In one particular embodiment of the present invention, an antioxidant is added to the meat products either prior to or following the step of irradiating the meat products in the first controlled atmosphere, to extend the color-life of the meat products.

Abstract: A bulk material irradiation system includes an input for inserting bulk material. A bulk material tube is connected to the input, forming a path for bulk material flow. A pressurizing assembly is connected to the bulk material tube for forcing the bulk material to flow through the bulk material tube. An irradiation assembly provides ionizing radiation to irradiate the bulk material passing adjacent to the irradiation assembly in the bulk material tube. Irradiated bulk material exits the bulk material tube through an output.

Abstract: An irradiation system includes a radiation source providing radiation in a localized radiation exposure area and a shielding structure around the radiation source. A conveyance system transports product into the shielding structure, through the radiation exposure region and out of the shielding structure. The conveyance system includes an input portion for carrying the product into the shielding structure at a first elevation. A first elevator moves the product from the first elevation to a second elevation different from the first elevation. A processing portion of the conveyance system carries the product at the second elevation through the radiation exposure region. A second elevator moves the product from the second elevation to a third elevation different from the second elevation. An output portion of the conveyance system carries the product out of the shielding structure at the third elevation.

Abstract: A system and method for providing irradiation to material shapes an electron beam into a profile having a substantially rectangular intensity distribution. The profile is deflected onto the material in a pattern with substantial overlap in a first dimension and without substantial overlap in a second dimension. In an exemplary embodiment, irradiation is provided to the material from first and second opposite sides.

Abstract: A bulk material irradiation system includes an input for inserting bulk material. A bulk material tube is connected to the input, forming a path for bulk material flow. A pressurizing assembly is connected to the bulk material tube for forcing the bulk material to flow through the bulk material tube. An irradiation assembly provides ionizing radiation to irradiate the bulk material passing adjacent to the irradiation assembly in the bulk material tube. Irradiated bulk material exits the bulk material tube through an output.

Abstract: An irradiation system includes a conveying system for moving material to be irradiated through a processing area. An irradiation source applies radiation to material in the processing area. The conveying system is enclosed by a sealed conduit in at least the processing area, providing the capability to control the atmosphere inside the sealed conduit and to clean the interior of the sealed conduit according to industrial sanitation methods.

Abstract: An electron beam accelerator system includes a high power switching device coupled between the direct current voltage source and the pulse forming network. A pulse control circuit is connected to control the high power switching device to selectively allow a current to flow to the pulse forming network. A voltage difference between a cathode and an anode structure creates an electron beam flowing therebetween. A control grid drive circuit is operatively coupled to the pulse control circuit and the control grid, and is operable to apply a time-varying voltage to the control grid synchronized with the pulse control circuit. The control grid therefore effectively provides a load on the high voltage output of a step-up transformer that prevents overshoot in the transformer output, reducing the risk of dielectric breakdown and failure due to transient high voltages.