from OP: /if I can make harmless the gamma rays of my mini-black hole for our biosphere./
I propose 2 ways, both involving ozone.
But first, how do incoming gamma rays hurt life on earth?
I knew that gamma radiation itself, while definitely bad for life, was not very problematic as regards extraterrestrial sources. It turns out that incoming gamma radiation expends itself on nitrogen molecules in the upper atmosphere. It creates reactive nitrogen oxides. It is the next step that is bad for life: reduced upper atmosphere ozone allows more UV radiation through and that is bad for life.
The long-term effects from a nearby burst are more dangerous. Gamma
rays cause chemical reactions in the atmosphere involving oxygen and
nitrogen molecules, creating first nitrogen oxide then nitrogen
dioxide gas. The nitrogen oxides cause dangerous effects on three
levels. First, they deplete ozone, with models showing a possible
global reduction of 25-35%, with as much as 75% in certain locations,
an effect that would last for years. This reduction is enough to cause
a dangerously elevated UV index at the surface.
On reading up I encountered the recently proposed theory that the Ordovician mass extinction was caused by a gamma ray burst.
So the problem is a 2 hit scenario: gamma rays deplete ozone, then UV gets thru. The ozone depletion (and the mechanism) is similar to what chlorofluorocarbons do. The "ozone hole" was much bruited about some years back but it seems that global bans on CFC are helping and the hole is healing. Could Lupetto take a page from the ozone hole playbook to fortify Mother Earth against the black hole?
There is bad ozone and good ozone. It is all ozone. Good ozone is good because it is far away. Sort of like good tigers. Bad ozone is bad because it is next to me and I breathe it.
What is Ground Level Ozone? (back to top) Ozone (O3) is a gas that
occurs in two layers of the atmosphere, the stratosphere and the
troposphere. The stratospheric or "good" ozone layer, which extends
upward from about 10 to 30 miles above the earth's surface, protects
life on earth from the sun's harmful ultraviolet rays (UV-b).
However, ozone found in the troposphere, the layer of the atmosphere
that extends from the earth's surface to about 10 miles up, is deemed
ground level or "bad" ozone. At ground level, ozone is an air
pollutant that damages human health, vegetation, many common
materials, and is a key ingredient of smog.
Idea 1 to protect the earth from gamma rays: More bad ozone. It is hard to increase ozone production high in the air. It is easy to increase it low in the air: smog is loaded with ozone. Although no-one writes this, ozone should stop UV wherever, high or low. I do not care if the bullet stops a kilometer from me or a centimeter from me, as long as it stops. So: a healthy ground blanket of ozone containing smog should be a failsafe against UV penetrating down thru a gamma-ray depleted ozone layer.
Idea 2 to fortify the ozone layer: Make more good ozone. This is harder. I was interested to read that the agents which are produced by the gamma rays are reactive oxides of nitrogen. These react with ozone and destroy it. It is these same reactive oxides at nitrogen, now reacting with volatile organic chemicals, that produce ozone at ground level! So injecting volatile organic chemicals into the upper atmosphere would serve double duty: protect ozone by giving reactive nitrogen species other playmates, and generate more ozone with the same reaction that occurs at ground level.
How Does Ground Level Ozone Form? (back to top) Ozone has the same
chemical structure (O3) whether it occurs miles above the earth or at
ground level. At ground level, "bad" ozone is formed when certain
compounds react in the presence of direct sunlight.
VOCs + NOx + Sunlight = Ozone
VOCs, (volatile organic compounds) are widely used as ingredients in
household products including; paints, varnishes, wax, fuels, cleaning,
disinfecting, cosmetic, degreasing, and hobby products. Some VOCs are
safe to handle and have little known health effects, while other VOCs
are highly toxic. In addition to all of the man made sources of VOCs,
natural sources of VOCs exist. For example, trees naturally release
small amounts of VOCs.
NOx, (nitrogen oxide gases) is the generic term for a group of highly
reactive gases, all of which contain nitrogen and oxygen in varying
amounts. Many of the nitrogen oxides are colorless and odorless. The
primary sources of NOx are motor vehicles, electric utilities, and
other industrial, commercial, and residential sources that burn fuels.
When high levels of VOCs and NOx are present in the air, they can
react. When they react in the presence of sunlight and hot weather,
ground level ozone forms.
Of these two I like the prospects for the first better. A smoggy world is not hard to achieve.