WiZard

Home page of the Experiment: http://WiZard.roma2.infn.it/

Satellite program

PAMELA mission

The observational objectives of the PAMELA experiment are the measurement of the spectra of antiprotons, positrons and nuclei in a wide range of energies, to search for primordial antimatter and to study the cosmic ray fluxes over half a solar cycle. The physical issues addressed by these observations include:

1. Role of Grand Unified Theories in Cosmology in relation to antimatter and dark matter.
2. Processes of acceleration and propagation of cosmic rays.
3. The relationship between solar, terrestrial and heliospheric processes and energetic particle propagation in the heliosphere.

This will be obtained through observation of:

1. Antiproton spectrum from 80 MeV to 190 GeV (current limit 49 GeV).
2. Positron spectrum from 50 MeV to 270 GeV (current limit 50 GeV).
3. Search of anti-nuclei with sensitivity of 10-8 for anti-helium/helium ratio (two orders of magnitude above current measurements).
4. Study of energetic and temporal distribution of solar flare phenomena.

The PAMELA experiment will be installed on the up-ward side of the Resurs DK1 satellite that will be continuously oriented downward to the Earth during all its mission, in order to fulfil a program of Earth surface observation. The satellite will travel in an elliptic (300-600 km altitude), quasi polar orbit with inclination 70.4 deg. This is a fairly good situation for the observation of cosmic rays.

NINA and NINA/MITA missions

The mission NINA-1 has been conceived to detect cosmic ray nuclei of galactic, solar or anomalous origin, from hydrogen to iron, between 10 and 200 MeV/n in regime of full containment, and up to a few GeV/n when the particles cross the detector. The experiment is carried out on board the satellite Resurs-01 n.4, developed by the Russian Space Company VNIIEM, which was launched in July 1998 from the base of Baikonur (Kazakistan) towards a polar sun-synchronous orbit at 840 km of altitude.

The weight and electric power of the complete telescope are respectively 40 kg and 40 W, in accordance with the constraints imposed by the satellite.

NINA-1, as per contract with the Russian Space Agency, has taken data until the end of 1999. During the year 1999 most of the work has been concentrated in the mission control and data taking and analysis. Results span over nuclear and isotopic composition of low energy cosmic particles, galactic cosmic rays, solar energetic particles and anomalous cosmic rays.

NINA-1 has been joined in space by a twin detector, NINA-2, also placed in a polar orbit but at a lower altitude (450 Km). NINA-2 is housed on board the Italian Space Agency Satellite MITA which was launched on July 2000 from the Plesetsk launch site in Russia by means of a Cosmos launcher.

NINA-2 mission plans to continue the NINA-1 mission extending its observational characteristics over time. NINA-2 was selected as the first payload of the technological flight of the satellite MITA. The detector is identical to the first one but makes use of the extensive computer and telemetry capabilities of MITA to improve active data acquisition time.

Balloon program

The first WIZARD balloon flight dates back to the 1989 and after that four more successful launches (1991, 1993, 1994, 1997-98) took place. CAPRICE98 (Cosmic AntiParticle Ring Imaging Cherenkov Experiment,1998) is the latest detector built and flown by the WIZARD collaboration. The CAPRICE98 instrument is composed of a superconducting magnet spectrometer associated to a tracking system made of three drift chambers, a gas RICH, a Time of Flight system and a silicon-tungsten electromagnetic calorimeter. The CAPRICE98 primary science goals were to measure the absolute spectra of positrons and antiprotons up to 50 GeV along with muon spectra in the atmosphere. A large part of positrons and antiprotons impinging on Earth are produced in high-energy interactions between cosmic rays nuclei with the interstellar medium. Their spectra can provide an insight on the origin, production and propagation of cosmic rays in our galaxy. Any observed flux larger than that predicted by the Leaky Box Model (LBM), the ``standard'' model of cosmic ray propagation, could indicate exotic sources of antimatter. The predictions of the propagation models are different above 10 GeV where more refined measurements are needed.

Muon energy spectra at different atmospheric depths are considered extremely important in the context of the atmospheric neutrino anomaly since they can help normalize the Monte Carlo predictions of neutrino fluxes. Recently, the importance of the primary spectra, used as an input for these calculations, has been pointed out; therefore, it is important to measure together primary and secondary spectra with the same detector, in the same day, in order to reduce systematic errors.

CAPRICE98 was successfully launched on the 28th of May 1998 from Ft. Sumner, NM, USA (340N,1040W), using the NASA National Science Balloon Facility (NSBF). The effective geomagnetic vertical cut-off is 4 GV/c for this site. The payload flew for 20h at a float altitude of 5g/cm2, corresponding to about 36 Km. More than 5 million triggers were collected during the flight and all detectors performed nominally.