Why X-Rays Beat Gamma Rays for Cannabis Decontamination

When it comes to post-harvest decontamination, X-rays outshine gamma rays
in efficiency, safety, and simplicity.

Decontamination is an essential part of post-harvest cannabis processing.
It helps eliminate mold and microbial contamination while ensuring overall
sterilization. Decontamination is very common in Canada, where cannabis is
legal and regulated at the federal level, as well as in some areas of the
United States, where cannabis is regulated state by state.

Irradiation—the process of sterilizing cannabis through radiation
technology—is one of the most effective ways to help ensure plant material
and the products made from it are safe for consumption. Two irradiation
methods, X-ray and gamma rays, are the most common. Although both have
proved safe and effective for cannabis, X-ray technology offers significant
advantages due to its ability to preserve the chemical makeup of the plant
while maintaining operational safety and efficiency standards.

To understand the differences between X-ray and gamma-ray decontamination,
it is essential to comprehend how they operate.

X-rays are produced during a process called electronic acceleration, which
causes high-energy electrons to collide with a target material. The
resulting X-ray photons penetrate almost everything in their path, damaging
the DNA of organic tissue. This renders microorganisms unable to reproduce
(sterile), eventually killing them. X-ray machines are encased in chambers
lined with lead—which X-rays cannot penetrate—to keep the photons from
escaping and damaging the DNA of unintended targets like nearby plants,
animals, and humans.

Small-footprint X-ray machines are convenient in our industry because
cannabis flower inside a sealed bag or jar can be loaded into a machine and
sterilized. Keeping the flower inside its original, sealed container
prevents recontamination after sterilization. X-ray sources can be turned
on and off, and the X-ray machine’s operator controls the dosage level.
Treatment has little effect on the product’s cannabinoid profile or terpenes,
which is key to maintaining product quality.

On the other hand, gamma-ray irradiation typically employs cobalt-60, a
radioactive isotope commonly used for sterilization. Gamma-ray equipment
emits a constant stream of radiation that cannot be turned on and off.
Exposure and sterilization levels are controlled by the distance between
the product and the gamma-ray source, as well as the duration of exposure.

Gamma-ray decontamination machines also use lead insulation, but they add
thick concrete walls to prevent external radiation exposure. The equipment
functions by emitting high-energy photons that disrupt pathogens’ DNA,
preventing them from functioning and reproducing. To decontaminate
properly, gamma rays require time, a controlled distance from the target,
and a suitable climate. Often, this method is used for sterilizing very
large quantities of plant material.

For most uses in our industry, X-ray decontamination is the superior
method. X-rays operate at lower energy levels (160–180kV) compared to gamma
rays (about 1,250kV), making them able to penetrate through packaging to
neutralize microbes without exposing the product to the air or altering its
chemical makeup. This translates to maintaining cannabis’s flavor,
fragrance, and other properties consumers enjoy.

In addition, X-ray systems are compact enough to be installed at
cultivation or processing facilities, eliminating the need for off-site
transportation. This not only reduces costs and logistical risks but also
ensures full chain-of-custody control during processing. Gamma-ray systems
use highly regulated radioactive isotopes. The equipment requires a lot of
floor space and expensive safety and monitoring equipment. Gamma facilities
are the size of a whole building, and products must be transported to the
gamma site for treatment; X-ray equipment can occupy a single room.

Unlike gamma rays, which require regulatory oversight by the Department of
Energy, X-rays utilize electrical power, a typical source for industrial
equipment, and commonly found in most grow facilities. X-ray
decontamination machines fall under standard safety protocols similar to
dental or medical X-ray equipment. The machines can be registered with
state programs, making them more accessible and manageable for most
businesses.

Gamma-ray decontamination systems are accompanied by significant initial
investments and ongoing costs associated with radioactive source
replenishment and containment infrastructure. By contrast, X-ray
decontamination systems are more affordable, with leasing and purchase
options available that fit the budget of most medium to large-scale
producers.

But X-ray solutions aren’t for everyone. While gamma-ray decontamination
systems can process extremely large volumes (many hundreds of pounds per
day), the highest-volume X-ray machines can handle just over 200 pounds per
day. That is sufficient for many cannabis operators, but those who need to
decontaminate large quantities of product on a regular basis may find X-ray
solutions inefficient.

While both X-ray and gamma-ray technologies can decontaminate cannabis,
X-rays can offer a superior edge to growers looking to prioritize quality,
safety, operational simplicity, and legal compliance. By providing the
ability to decontaminate on site, preserve the plant’s chemical properties,
and avoid complexities in handling radioactive materials, X-ray machines
offer a practical and cost-effective solution for most producers.
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[image: Jeff Adams XR Pure]

*As founder and managing director at XRPure, Jeff Adams oversees a company
propelling innovation in cannabis decontamination using X-ray energy. His
thirty years of experience in industrial manufacturing operations spans
process engineering, quality management, operations management, sales, and
general management. Adams earned a master’s degree in mechanical
engineering from MIT and an executive MBA from Brigham Young University.*

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Zap the Crap: Cannabis Decontamination Explained

1. Why is decontamination important in cannabis processing?

Decontamination ensures cannabis products are free from mold, microbes,
and other contaminants, making them safe for consumption and compliant with
regulatory standards.
2. What is the difference between X-ray and gamma-ray decontamination?

X-ray decontamination uses electronically generated radiation that can
be turned on and off, offering precise, low-energy sterilization that
preserves the cannabis plant’s chemical makeup. Gamma-ray systems use
radioactive isotopes like cobalt-60, emit constant high-energy radiation,
and are better suited for bulk sterilization but involve more regulatory
oversight and infrastructure.
3. Is X-ray sterilization safe for cannabis products?

Yes. X-ray sterilization is considered safe and effective for cannabis,
with minimal impact on cannabinoids and terpenes. It can be used on sealed
packaging, reducing the risk of recontamination.
4. Can cannabis be decontaminated on-site?

Yes. Compact X-ray decontamination systems can be installed directly in
cultivation or processing facilities, offering on-site sterilization
without the need for transport to off-site gamma-ray facilities.
5. Which decontamination method is more cost-effective for cannabis
operators?

X-ray systems are typically more affordable and accessible for small to
mid-sized producers. Gamma-ray systems, while effective for high-volume
processing, require significant investment and regulatory oversight.