In June 1998 a new cosmic ray detector started to operate in
Israel on Mt. Hermon at 2200 m a.s.l. This experiment has been established in
collaboration between IFSI/CNR ((Italy), University "Roma Tre" (Italy)
and Tel Aviv University (Israel). The cosmic ray detector has been located
inside a mobile laboratory which was used in the past by the Italian groups to
perform cosmic ray latitude surveys in Europe. Beginning from May 1997, when the
School of Physics and Astronomy of Tel Aviv University had undertaken to support
the research program in Cosmic Ray Physics and Astrophysics in Israel, the
involved groups started to organize the experiment.
The experiment was assembled in Italy and transferred to Israel at the beginning
of June 1998 and it started to operate during the same month.
This cosmic ray detector will be of great importance for the international
scientific community because it fills a gap in the worldwide network of cosmic
ray stations. Moreover, the very high statistics (about 6.105/hour)
allows the use of the data in short-time scale (minutes) for the study of solar
particle events and of precursory features of interplanetary disturbances.
In a near future the experiment will start to investigate the effect of enhanced
atmospheric electricity on the neutron monitor counting rate. This will be done
by implementing the experiment by new instrumentation for measurements of
atmospheric electricity.
The neutron detector is formed by two independent 3NM-64 sections. The total
counting rate and multiplicities from 1 to 8 are recorded every minute, together
with the values of barometric pressure, internal and external temperatures,
internal relative humidity, wind velocity and direction, low and high voltages
values. Cosmic ray data must be corrected for changes in the mass of air over
the detector (barometric effect). The computation of the mass of air should take
into account the influence of wind (Bernouilli effect) which produces an
apparent decrease in the mass of air (being Mt. Hermon a very windy location,
this correction becomes important).
The laboratory is protected by a ad hoc constructed Faraday grid, to
prevent lightning activity (particularly strong in this area) to damage the
experiment.
During the first months of activity, the behavior of the detector and recorded
data have been tested and proved to be reliable, according to the preliminary
tests performed in Italy.
It is planned to run this experiment continuously for at least
20 years.
Dr. M.Storini, F. Re, F. Signoretti (IFSI/CNR)
Prof. N. Iucci,
Dr. G. Villoresi (University "Roma Tre")
Prof. L.I. Dorman (Israel Cosmic Ray Center)