Abstract:
Contamination is reduced by exposing a specimen to light, such that the light includes ultraviolet and light of wavelength in the visible region, so that the light in the visible region damages the shell of an organism and the ultraviolet light prevents reproduction of the organism.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims priority to, and incorporates by reference, U.S. provisional patent application No. 60/476,494, filed Jun. 6, 2003. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to methods and systems for decontamination. More specifically, the present invention relates to methods and systems using lighting at various frequencies and/or wavelengths to destroy spores, bacteria, other microorganisms or other living organisms such as cells or mites.  
       BACKGROUND  
       [0003]     Deadly or otherwise harmful spores, viruses and other bacteria plague our environment. Many technologies have arisen to respond to this problem. For example, to eliminate and/or reduce the growth of bacteria in foods, various methods of irradiating food have been developed. Deadly and/or disease-causing spores can be found in other locations as well, as demonstrated by the discovery of anthrax and various letters sent through the United States mail. Such spores, bacteria, viruses and microorganisms can spread naturally, such as through normal daily human contact, or they can be introduced artificially, such as through terrorism or other human intervention.  
         [0004]     Prior methods to eliminate and/or prevent the growth of such microorganisms typically include the use of high power radiation to kill the microorganisms. Ultraviolet light, and in particular UV-C light having a wavelength of approximately 254 nm, is known to damage the DNA of bacteria, viruses and other pathogens by forming covalent bonds between adjacent thymine bases in their DNA. This action prevents the organism from reproducing. Thus, some systems have used ultraviolet light to provide decontamination effects. Other systems, such as that described in U.S. Pat. No. 6,268,200, have used microwave energy to achieve similar results. In each case, such systems typically require high power and/or long exposure to the light for decontamination to occur, and they are not effective to kill many types of organisms.  
         [0005]     Accordingly, an improved system and method for destroying unwanted organisms is desired.  
       SUMMARY OF THE INVENTION  
       [0006]     In an embodiment, one or more lamps capable of emitting light of various frequencies and/or wavelengths are used to destroy organisms. An electronic controller, such as an electronic ballast bursting unit™ (“EBBU™”), may be used to adjust the wavelength of the light emitted by the lamps based on the type of organism to which the light will be administered in an embodiment.  
         [0007]     In another embodiment, a method of reducing contamination includes exposing a specimen to ultraviolet light and exposing the specimen to light at one or more selected wavelengths in the visible region. The irradiance of the light at the one or more selected wavelengths in the visible region will be sufficient to accelerate damage to one or more organisms in or on the specimen, typically, by opening a skin, outer membrane or other shell of the one or more organisms. The one or more selected wavelengths in the visible region may be selected based on the one or more organisms for which contamination reduction is desired. The exposure to ultraviolet light and the exposure to visible light may occur simultaneously. The ultraviolet light may comprise light at a wavelength of approximately 254 nm. Optionally, the method may include simultaneously exposing the specimen to light at one or more wavelengths below 200 nm at an intensity sufficient to produce ozone.  
         [0008]     In an alternate embodiment, a decontamination system includes a power source, a lighting controller, and one or more ultraviolet lamps. When controlled by the lighting controller, the lamps will emit ultraviolet and visible light. The visible light will include light at one or more selected wavelengths at intensities sufficient to accelerate damage to an organism exposed to the light. The lamps may be made of quartz glass, and in an embodiment they may contain a gas mixture of at least argon and krypton, although any germicidal gas mixture may be used in other embodiments. The controller may include a frequency generator that adjusts the irradiance of the light emitted at one or more of the wavelengths so that the adjusted intensities of the light emitted at the selected wavelengths are near the intensity of the emitted ultraviolet light. For example, the frequency generate may be a pulse width modulator. Optionally, the controller includes one or more transformers having at least one winding comprising multistranded wire.  
         [0009]     In an alternate embodiment, a lighting controller includes a frequency generator and an output to receive and deliver power to one or more lamps. The frequency generator adjusts the frequency of a signal delivered to the output so that, when the output is connected to one or more bulbs, the bulbs emit radiation at a frequency that will crack the shell of an organism. The output also delivers power to the one or more bulbs so that the one or more bulbs will emit light at approximately 254 nm. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a block diagram illustrating exemplary elements of an Electronic Ballast Bursting Unit (“EBBU”), lamp(s) and enclosure, optional diffuser, treating area and specimen(s) to be decontaminated.  
         [0011]      FIG. 2  illustrates exemplary light output of a standard ozone-providing germicidal bulb.  
         [0012]      FIG. 3  illustrates exemplary output of a germicidal bulb in accordance with an embodiment of the present invention.  
         [0013]      FIG. 4  illustrates an embodiment of an EBBU as it may be used to drive a group of fluorescent lamps.  
         [0014]      FIG. 5  illustrates input and filter stages of the embodiment of  FIG. 5 .  
         [0015]      FIG. 6  illustrates elements of the DC rectifier stage of  FIG. 4 .  
         [0016]      FIG. 7  illustrates exemplary elements of the power factor correction stage of  FIG. 4 .  
         [0017]      FIG. 8  is a block diagram of a prior art power factor correction circuit.  
         [0018]      FIG. 9  is a block diagram of an exemplary frequency generator circuit.  
         [0019]      FIG. 10  is a block diagram of an alternate frequency injection circuit.  
         [0020]      FIG. 11  illustrates exemplary elements of the output stage of  FIG. 4 .  
         [0021]      FIG. 12  illustrates an embodiment of the feedback stage of  FIG. 4 .  
         [0022]      FIG. 13  illustrates further features showing the output being used to drive a fluorescent lamp.  
         [0023]      FIG. 14  illustrates a portion of an alternate controller apparatus that may be used with an embodiment of the system.  
         [0024]      FIG. 15  illustrates additional portions of the alternate controller apparatus of  FIG. 14 .  
         [0025]      FIG. 16  illustrates the emission of light at various exemplary wavelengths to destroy various organisms and prevent them from reproducing. 
     
    
     DETAILED DESCRIPTION  
       [0026]     Referring to  FIG. 1 , in a system embodiment of the present invention, an electronic controller, such as an electronic ballast bursting unit (“EBBU”)  100  may be used to deliver and adjust the frequency of power delivered to one or more ultraviolet lamps  91  and  92 . The lamps may be situated under a hood or in an enclosure  200  that includes the treating area  210 . One or more objects  212  that are to be decontaminated may be placed or passed under or near the bulb(s) and travel through or sit within the treating area. Optionally, the treating area  200  may include a hood with a light diffuser  214  made of materials such as honeycomb or angled reflective material to direct the light from the lamps into an area for treatment and minimize or prevent the diffusion or stray illumination of light. Optionally, the enclosure  200  may include a filter or shield to prevent the user&#39;s eyes from being damaged by the emission of light inside of the enclosure.  
         [0027]     A specimen to be decontaminated is placed in proximity to the lamp or lamps, and the EBBU is used to deliver a wavelength of light that is appropriate to quickly and efficiently kill bacteria, spores or other organisms on or in the specimen.  
         [0028]     For example, as illustrated in  FIG. 2 , a standard ultraviolet bulb may deliver light at a wavelength at or near 254 nanometers (nm). In addition, an ozone-producing bulb may deliver light at lower wavelengths, such as 180 to 185 nm, which may produce ozone. The ozone and approximately 254 nm light are known to those skilled in the art to have germicidal properties.  
         [0029]     Surprisingly and advantageously, I have found that increasing the intensity of light at higher wavelengths, and in particular specific wavelengths in the ultraviolet and visible regions, may accelerate and/or promote decontamination. In particular, while the prior art has taught that light in the visible region will not possess germicidal properties, I have found that certain focused visible light intensities may accelerate the germicidal activity of ultraviolet light. For example, as illustrated in  FIG. 3 , increasing the irradiance, or intensity of light at approximately 365 nm, 405 nm and 436 nm may significantly accelerate decontamination of  Bacillus atrophaeus  or  Bacillus stearothermophilus , while increased irradiance at approximately 546 nm and 579 nm may accelerate decontamination of the niger virus. As shown in  FIG. 3 , some or all of these intensities may be increased to be substantially equal to the irradiance of 254 nm ultraviolet light from the bulbs.  
         [0030]     An exemplary circuit diagram showing an embodiment of an EBBU is illustrated in  FIG. 4 . As indicated in  FIG. 4 , the EBBU  100  may include as many as seven stages or more, each of which provides additional features for the system.  
         [0031]     Referring to  FIG. 4 , in the illustrated embodiment the first stage of the device  10  receives an input voltage and operates as an AC power supply. The input stage  10  may accept an input voltage that is at least between the range of 80 and 300 volts, although other voltages are possible depending on the load to be driven. The second stage  20  functions as electromagnetic interference (EMI) filter. The third stage  30  functions as a DC rectifier, converting the AC input voltage to a DC voltage, with a connection to a feedback circuit. The fourth stage  40  operates as a power factor correction stage. The fifth stage  50  operates as a high-voltage power filter. The sixth stage  60  operates as the output stage to deliver power to one or more bulbs or other devices. The seventh stage  70  is a general feedback stage. Although  FIG. 4  as illustrated defines a boundary for the feedback stage  70 , the boundary is only intended to illustrate a portion of the feedback stage  70 . In fact, feedback may be provided to each of stages  30 ,  40 ,  50  and  60 .  
         [0032]      FIG. 5  through  FIG. 13  provide additional detail of certain embodiments of the individual stages described above and illustrated in  FIG. 4 . The values listed below for individual elements are exemplary values only and should not be interpreted as limiting. Persons skilled in the art will recognize that other values are possible without departing from the spirit and scope of the invention. In addition, one skilled in the art will recognize that other circuits may be used to achieve similar results. Additional details of exemplary circuits are disclosed in the co-pending U.S. patent application entitled “Lamp Driver,” filed Apr. 30, 2004, having Ser. No. 10/835,839, which is incorporated herein by reference in its entirety.  
         [0033]     Exemplary elements of input stage  10  and second stage  20  are illustrated in  FIG. 5 . Referring to  FIG. 5 , input stage  10  includes a power source, optionally between 80 and 300 volts, or plug  16  at AC inputs  11 A and  11 B, a line fuse  12  such as a 4-amp fuse, and two varistors  13  and  14 . In the illustrated embodiment, the power source may be a 120V, 60 Hz voltage source, and the line fuse  12  may be a 4 amp fuse for a driver for two 120-watt lamps. When the circuit is used to light higher intensity lamps or additional numbers of lamps (such as four 120-watt lamps), larger fuses may be needed. Varistors or zener diodes  13  and  14  may function as surge protection devices connected between each of the AC inputs and ground  17 . When a power surge or voltage spike is exhibited on the AC inputs, the resistance of varistors or zener diodes  13  and  14  may quickly decrease, creating a shunt path for the over-voltage. In this way, other components in the device may be protected from power surges.  
         [0034]     The EMI filter stage  20  of the device may function as a noise filter. In the filter stage, an LC filter may be replicated between each AC input  11 A and  11 B and ground. The LC filters operate as noise filters to remove unwanted frequencies from the AC voltage input source. The LC filters may, be composed of optional inductors  21  and  22  (not shown in  FIG. 5 ), and capacitors  23  and  24 . In an embodiment, the inductors  21  and  22  may have an inductance of approximately 600 nH, and capacitors  23  and  24  may have a capacitance of approximately 2.2 nF. Capacitor  25  may have a capacitance of 1.0 μF. Other values are possible without departing from the spirit and scope of the invention.  
         [0035]     The DC rectifier stage  30  may convert the AC input signal into a DC signal. Exemplary elements of the DC rectifier stage  30  are illustrated in  FIG. 6 . Diode bridge  31  functions as a full wave bridge and converts the AC input voltage into a DC output voltage. Diode bridge  31  may be made of a full wave rectifier, or it may be four separate diodes, such as 4-amp diodes. The use of separate diodes instead of a rectifier is preferred when bulbs having a higher total wattage are used. Diode bridge  31  may be connected to the feedback stage  70  via the ground plane. The connection between diode bridge  31  and ground may stabilize the voltage differential across the bridge. Optional thermal cutout component  32  may operate as a temperature-sensitive, protective device to shut down the operation of diode bridge  31  in certain thermal conditions. For example, thermal component  32  may trigger a shut down when it senses an external temperature of 105° C., which may indicate a fire.  
         [0036]     Exemplary elements of the power factor correction stage  40  are illustrated in  FIG. 7 . A coil device  41  operates to boost the output voltage based on the lamp or lamps (or other device or devices) attached to the output of device  100 . A coil device  41  using multistranded wire is described in co-pending U.S. patent application Ser. No. 10/834,778, entitled “Coil Device”, filed Apr, 29, 2004, which is incorporated herein by reference in its entirety. Other coil devices are possible without departing from the spirit and scope of the invention. The coil device preferably includes a secondary winding to allow it to serve as a transformer for the delivery of power to the bulb or bulbs. The power factor correction circuit may be used to make a nonlinear load operate like a resistive load by putting it into phase. In one embodiment used to power two 120-watt fluorescent bulbs, the power factor correction controller  42  may be a Fairchild Semiconductor FAN7527 or similar device. The power factor correction controller  42  may be used along with one or more resistors  44 - 48 ; one or more capacitors  49 ,  141  and  144 ; one or more diodes  142  and  143 ; a coil device  41 ; and MOSFET  145  to create a power factor correction circuit. In the embodiment corresponding to  FIG. 4 , resistors  43 ,  44 ,  45 ,  46 ,  47  and  48  may have values of approximately 180 Ω, 10Ω, 22 kΩ, 2.2 MΩ, 27 kΩ, and  0 . 25  Ω, respectively, while capacitors  49 ,  141 ,  144  and  145  may have values of approximately 1 nF 1 μF, 1 μF and 1 MF, respectively. The embodiment shown in  FIG. 5  may also include a diode  151 .  
         [0037]     In the embodiment illustrated in  FIG. 7 , the power factor correction device  42  includes a two-stage power factor correction microchip. An example of such a microchip is the FAN7527B supplied by Fairchild Semiconductor. The two-stage microchip uses substantially the same frequency for pre-startup heating and actual startup, thus providing a power saving advantage. The operation of a prior power factor correction microchip is described in Fairchild Application Note AN4107, published May 2000, and is illustrated in  FIG. 8 .  
         [0038]     Exemplary elements of a high voltage power filter stage  50  are also illustrated in  FIG. 7 . In one embodiment stage  50  may incorporate resistor  51  and variable resistor  52 . In an embodiment, resistor  51  may have a resistance of about 1.1 MΩ, and variable resistor  52  may have a peak resistance of about 10 kΩ. The optional variable resistor  52  may be used to adjust the frequency of the output signal by changing its voltage, since a higher voltage will result in a higher frequency. A higher frequency of the output signal may also change the irradiance of one or more wavelengths of the light emitted by the bulb or bulbs. Optional resistor  148 , such as a 6 kΩ resistor, may also be used.  
         [0039]     In an alternate embodiment, the frequency may be adjusted using a frequency generator  270  such as an off-the-shelf or custom frequency generator. An exemplary off-the-shelf frequency generator is a Hewlett Packard HP8094 multi-function synthesizer. Alternatively, a frequency generation circuit such as that illustrated in  FIG. 9  may be used. In the embodiment illustrated in  FIG. 9 , a timer  302  sets up a frequency and delivers a signal to a pre-settable synchronizable up/down counter such as a four-bit counter  304  set to provide a one-bit output every 30 seconds. The counter  304  induces a second frequency to allow mixture of two frequencies. One or more multiplexers  305   a  and  305   b  may also establish a time count for a digital-to-analog converter  307  and analog-to-digital converter  308  in the circuit. A switch such as a DIP switch  306  with optional pull-down resistors  309  may allow a user to adjust the accuracy of the injected frequency. The signals are delivered through analog-to-digital converter  307  and digital-to-analog converter  308  to a lamp driver output  310 . Optionally, a variable resistor  312  may allow further adjustment of the frequency before it is delivered to the lamp driver. One or more decimal decoders  311   a  and  311   b  may act as counters, a switch  315 , and one or more comparators  317  and  319  may also be present.  
         [0040]     An alternate frequency injection circuit is illustrated in  FIG. 10 . Referring to  FIG. 10 , a pulse width modulator (PWM)  402  such as a Texas Instruments TL594 chip receives power from a power supply  404  with an optional switch  406  and diode  408  for controlling the circuit. With a variable resistor  410  such as one having a range of up to 5 KΩ, the PWM may be used to adjust and control the frequency delivered to an output  412 , which is connected to the EBBU. Resistors  412  and  416  and capacitor  420  may have values of 19.1 KΩ, 1 KΩ, and 0.047 μF, respectively. Other values are possible. Optional light-emitting diode  422  may indicate when the circuit is powered.  
         [0041]     Referring again to  FIG. 7 , capacitor  146  illustrated in  FIG. 7  may have a resistance of between 47 MF and 100 MF. Other values are possible. In either embodiment (i.e., with a variable resistor or a frequency injector), the frequency of the output signal may be varied so that the lamp or lamps connected to the output of the ballast device emit light having increased irradiance at one or more focused wavelengths, selected based on the attributes of the bulb or bulbs to be driven and the organism for which decontamination is desired. Exemplary wavelengths are described in more detail below.  
         [0042]     Exemplary elements of an output stage  60  are illustrated in  FIG. 11 . Referring to  FIG. 11 , a controller  61  may be implemented by a ballast controller such as a Fairchild Semiconductor KA7540 or KA7541 or a similar device. The controller  61  may be used to produce the high output voltage required to drive the output MOSFETs  62  and  63  in conjunction with a standard gate driver  64 . The MOSFETs  62  and  63  may blend the injected frequency component output from stage  50  or the optional frequency injector  270  and the high voltage driven from the standard gate driver  64  to produce the proper signal to the lamps and/or bulbs. The drain port of MOSFET  62  may be driven by stage  50  at a high voltage (such as 400 volts), and it may receive a pulse input at a frequency determined by the variable resistor  52  or frequency generator  270 . The resulting output of MOSFETs  62  and  63  may be a DC square wave or substantially square wave.  
         [0043]     Preferred, although not required, values for various elements in  FIG. 11  are that resistors  263 ,  66 ,  67 ,  68  and  69  may be approximately 51 Ω, 150 KΩ, 22 KΩ, 51 Ω and 51 Ω, respectively. Variable resistors  261  and  262  may each have values of between 1 KΩ and 100 KΩ. Capacitors  162 ,  163 ,  164 , and  165  may be approximately 56 pF, 0.22 μF, 47 MF, and 0.22 μF, respectively. Varistor  167  may be a 15 volt Zener diode. Diodes  265 ,  266 ,  267  and  268  may be, for example, 300 volt diodes. In each case, other values are possible.  
         [0044]     The use of a Fairchild Semiconductor KA7541 as controller  60  is illustrated in  FIG. 11 . However, in an alternate embodiment, a different controller  61  may be used.  
         [0045]     Referring to  FIG. 12 , feedback stage  70  is a general feedback stage in which the output voltage level is transmitted to other stages to permit for corrections in the total voltage differential in the circuit. Referring to  FIG. 12 , exemplary values for resistors  71 ,  72 ,  73 ,  74 ,  75 ,  76 ,  77  and  78  may be 10 KΩ, 10 KΩ, 442 KΩ, 220 KΩ, 150 KΩ, 10 KΩ, 200 KΩ and 442 KΩ, respectively, while exemplary values of capacitors  171 ,  172 , and  173  may 0.22 nF, 1 mF and 1 μF, respectively. Other values are possible. The feedback stage  70  may also serve as a circuit to turn off MOSFETs  62  and  63  when no bulbs are not installed in the system. Although  FIG. 12  illustrates a boundary for the feedback stage  70 , the boundary is only intended to illustrate a portion of the feedback stage  70 . In fact, feedback may be provided to each of stages  30 ,  40 ,  50  and  60 .  
         [0046]     The output waveform of the device may drive one or more bulbs to produce light having increased intensities at one or more desired wavelengths. Referring to  FIG. 13 , if one or more fluorescent bulbs  91 A and  92 A are driven, a coil device  82  similar to the one illustrated in stage  40  may be used to convert the DC square wave output from stage  60  of the ballast device into an AC sine wave. An exemplary coil device  82  is a multistranded wire device with a secondary winding as illustrated in pending U.S. patent application Ser. No. 10/834,778, filed Apr. 29, 2004, entitled “Coil Device”, which is incorporated herein by reference in its entirety.  
         [0047]     If two or more fluorescent lamps are connected, they may be connected in series as illustrated in  FIG. 13 . Each combination of two fluorescent lamps preferably has a single associated coil device. Additional configurations with additional lamps are possible.  
         [0048]      FIGS. 14 and 15  illustrate an alternate driver circuit that may be used to implement the present invention. Such a circuit may include elements of a circuit such as that disclosed in U.S. Pat. No. 5,287,040, of which FIG. 2 (parts 1-4) and the accompanying text are incorporated herein by reference in all aspects. Referring to  FIGS. 14 and 15 , a suitable circuit may differ from that disclosed in U.S. Patent No. 5,287,040. For example, the circuit may include a frequency injector or modulator  270  such as those described above and illustrated in  FIGS. 9 and 10  in order to provide output from the bulb or bulbs at elevated wavelengths. The modulator  270  may be connected to the circuit, for example via an optical isolator  855  such as one known as a 4N25 optical isolator. In addition, various component values will differ. Referring to  FIG. 14 , when used with two 120-watt fluorescent bulbs, or even in certain embodiments with brighter bulbs, resistors  811  and  817  may be 100Ω and 3.32KΩ, while capacitors  823  and  829  may be 100 μF and 820 μF. In addition, transformers  813  and  883  may be made with multistranded wire, such as the transformers disclosed in U.S. patent application Ser. No. 10/834,778, filed Apr. 29, 2004, entitled “Coil Device”, which is incorporated herein by reference in its entirety. Preferably, at least the secondary winding of each transformer is made with multistranded wire. Referring to  FIG. 15 , resistors  831  and  835  may be 14.7 KΩ and 100 KΩ, respectively, while capacitor  869  may be 0.047 1 μF, and no resistor may be required at line  821 . The value of resistor  897  may vary, or it may be replaced with a variable resistor. Such changes may permit the circuit to increase the intensity of desired wavelengths of light output. One skilled in the art will also recognize that other values are possible, and that the values may be changed depending on the desired output wavelengths and intensities. Further, not all elements of  FIGS. 14 and 15  may be necessary for the application of the present invention. For example, lamp sensing circuitry and/or rectifier circuitry may not be necessary.  
         [0049]     Referring again to  FIG. 13 , in an embodiment the invention uses one or more germicidal bulbs or lamps such as  91 A and  92 A capable of emitting ultraviolet radiation of various wavelengths. These lamps are similar to conventional germicidal ultraviolet lamps, commonly referred to by those skilled in the art as T5 bulbs. However, the bulbs maybe longer than standard T5 bulbs, which are up to 36 inches long. In one embodiment, the preferred bulbs are of a length substantially equivalent to that of a T12 bulb (i.e., approximately four feet long). The longer bulb allows a greater intensity of output than would normally be expected from a T5 bulb. The diameter of the bulb is also that of a standard T12 bulb, although each end of the bulb may be been modified to have few inches where the diameter is that of a T5 bulb. This effectively allows a T12 bulb to be inserted into T5 bulb&#39;s socket.  
         [0050]     The bulbs may be constructed of high quality quartz or another appropriate material. It may also include a filter to absorb visible light. The gas mixture in the bulb can be the standard mixture that is expected in a germicidal ultraviolet bulb, such as a mixture containing approximately 65% argon, a percentage of krypton, and optionally a trace of mercury. The gas may be present at a pressure that elevated from the pressure of an ordinary T5 bulb by as much as four times or more. Surprisingly, although mercury-containing bulbs can be used with the present invention, I have found that a mercury-free bulb can be used in the present invention.  
         [0051]     The lamps may include filaments. However, in an embodiment the lamps do not include filaments, thus allowing the lamps to be lit at extremely low temperatures because there is no need to heat the filament as in previous systems. Each lamp may also have two unconnected, single electrodes through which power can be supplied.  
         [0052]     Conventional Type UV-C bulbs only deliver most intensities of ultraviolet light at a wavelength of approximately 240 to 255 nm. While some irradiance is also emitted in the visible region, the irradiance of the ultraviolet region is much higher than the irradiance of any wavelength of the visible region. With an unconventional bulb such as that described above, or with an EBBU and a conventional germicidal bulb, or with an EBBU and an unconventional bulb, a wide range of wavelengths can be used to destroy a wide variety of organisms. The use of an EBBU such as that described above allows the user to blend the output light so that ultraviolet light (i.e., that having a wavelength of approximately 254 nm) can be emitted along with light of other, preferably higher, wavelengths. The wavelengths may be selected by adjustment of the varistor in stage  50  and/or the frequency injector in stage  60  of the EBBU to deliver different output frequencies, and the particular frequency (and corresponding wavelength) that is selected will depend on the organism for which decontamination is desired.  
         [0053]     For example, as illustrated in  FIG. 16 , I have surprisingly found that in addition to the bulb&#39;s normal operating wavelength of approximately 254 nm, the EBBU may blend the input frequencies to one or more bulbs to increase the irradiance of emitted light at wavelengths of approximately 405 nm and 422 nm to open the outer shell of some or all  bacillus  spore types. The outer shell of the niger virus can be opened by increasing the intensity of emitted light at approximately 546 and 579 nm. When performed in connection with the normal emissions of ultraviolet light at 254 nm, the higher wavelength opens the spore, such as by cracking its outer layer, skin, outer membrane, or other shell, while the ultraviolet light damages the DNA and ensures that the organism will not reproduce. Put differently, the emitted light includes radiation emitted at a frequency that is sufficient to crack a shell of an organism. With an ozone-producing bulb, additional decontamination may be possible, even if the specimen to be decontaminated is not placed directly under the bulb(s).  
         [0054]     The bulb is powered by the EBBU to emit various wavelengths of light, and at frequencies and for various times to kill various types of spores. The specific wavelength, frequency and/or time of application can be adjusted based on the organism that is desired to be destroyed.  
         [0055]     As described above, the bulb can be mounted in several forms, such as in a ventilator or other hooded or enclosed device. The material containing the organism, such as food, mail, and/or other material, is placed below or in close proximity to the bulb. The distance between the bulb and the material is not essential to killing the organism. However, the further that the bulb is placed away from the material, the greater amount of time that will be required to kill the organism or organisms. One skilled in the art will recognize that at some point the distance will become so great that the light from the bulb will not reach the material in any concentrated amount and thus will not likely kill the organism. The time required to kill an organism may also be dependent on the thickness of the product containing the organism, such as an envelope, air, water, soil, human or animal tissue and/or vegetables or grains.  
         [0056]     The EBBU may take on various embodiments in addition to that described above, although in each embodiment it allows the bulb(s) to emit light at various wavelengths. In an embodiment, the EBBU is a low power device that can operate on a common 120-volt circuit (or other standard voltage circuits as necessary outside of the United States). Other designs are possible, such as a unit that will operate between 80 volts and 300 volts on a 50/60 Hz signal.  
         [0057]     The EBBU may be used in various applications. For example, the apparatus and system may be used to kill spores in food products. It can kill bacteria and/or prevent the growth of bacteria in food products. It also may be used to kill anthrax in various applications, such as when placed in a mail sorter or other letter delivery system. It may be used to destroy germs, molds, mites, cysts, abnormal cells or other organisms. The system may be placed in water treatment plants or home water purification systems to eliminate bacteria and viruses from drinking water. It may be used to decontaminate surgical instruments and other medical equipment. Finally, the method and system can be used to decontaminate air that has passed through a decontamination system using the present invention. Additional applications not described herein are possible and considered to be within the scope of the present invention.  
       EXAMPLE 1  
       [0058]     In one example, an EBBU with a germicidal lamp was tested to determine the time it would take to destroy  bacillus  spores. Four spore strips were exposed to targeted ultraviolet light at zero seconds, 30 seconds, 60 seconds and 120 seconds, respectively. Each spore strip was positioned approximately nine inches from the bulb. One type of spore strip included  bacillus stearothermophilus  and was incubated at 55° C. for 14 days prior to exposure to the light. Other spore strips included  B. subrilis var. niger  and was incubated at 35° C. for 14 days prior to exposure to the light. At one second, the bulb output wattage varied up to approximately 190 watts. At 30 seconds, the bulb output wattage varied between 175 watts and 285 watts. At 60 seconds, the bulb output wattage varied between 182 watts and 289 watts. At 120 seconds, the bulb output wattage varied between 171 watts and 291 watts. Irradiance levels of light emitted at approximately 405 nm and 422 nm that were similar to the irradiance levels of UV-C light opened and destroyed the  bacillus  spore types, while similar combinations of UV-C and light at 405 nm and 502 nm opened and destroyed the niger virus.  
         [0059]     It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in this description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Hence, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.  
         [0060]     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.