NA32, "Investigation of Charm Production in Hadronic Interactions Using High - Resolution Silicon Detectors" was a research project at
CERN. The project was approved on 18 November 1982, data taking completed on 20 August 1986 and the analysis of the results was formally considered finished on 20 August 1996.
The experiment was also known as ACCMOR, an acronym of the names of the collaborating research institutes which carried it out — the
Amsterdam
Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the capital and most populous city of the Netherlands, with The Hague being the seat of government. It has a population of 907,976 within the city proper, 1,558,755 in the urban ar ...
-
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
-CERN-Cracow-
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and Ha ...
-
Rutherford Collaboration, which was also responsible for the
WA3 experiment.
The experiment was designed to measure precisely the momentum of
charged particles
In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. It can also be an electron or a proton, or another elementary particle, ...
emerging from high energy
hadron
In particle physics, a hadron (; grc, ἁδρός, hadrós; "stout, thick") is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the e ...
interactions and identify these particles over a large range of momenta. Experimental setup consists of two large
spectrometer
A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...
magnets, 48 planes of drift chambers arranged in several arms and 4 multicell threshold Cerenkov counters. A
calorimeter
A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal micro calorimeters, titration calorimete ...
at the end was used to measure the position and energy of photons and electrons.
The target region consisted of:
# A telescope of seven silicon micro-strip detectors to measure the incoming beam.
# A forward vertex detector to track precisely secondary particles produced in high energy hadronic interactions.
# A 2.5 mm thick copper target.
Microstrip detectors used in the NA32 experiment come from three different sources: (i) most of the detectors used in the charm experiment were produced by J.Kemmer at the TU Munich following a technique developed earlier by Kemmer. (ii) In an early stage of the experiment (1982) four detectors in the beam telescope produced by ENERTEC, Strasbourg were used. (iii) In 1984 and 1985 two prototype detectors produced by MICRON, England were put into the experiment for specific tests.
The pixel size of the NA32 detectors was 22 x 22 μm, and the effective detector thickness ~15 μm. The relatively shallow active area lead to a very small signal demanding cooling and very low noise electronics. In the NA32 the data was read out at a rate of 1.5-3 MHz, allowing ~50 000 pixels to be read out in 16 ms.
NA32 proved that tracking using silicon microstrip detectors was a practical technique for resolving particle tracks over very short distances, and in particular for detecting short-lived particles down to half lives of fractions of picoseconds.
See also
*
List of Super Proton Synchrotron experiments
References
Further reading
A.Ali, P.Soeding. High Energy Electron-positron Physics, 1988. p. 373
External Links
* CERN-N
32 experiment record on
INSPIRE-HEP
{{SPS experiments
Particle experiments
CERN experiments