ABSTRACT
As minerals, aromatic compounds occur very rarely in nature. Not more than 10 of such minerals are known and most of them were described in the coal deposits where they were formed as a result of coal bed fires or burning of coal waste heaps. Raman spectra of kladnoite C(6)H(4)(CO)(2)NH (natural phthalimide) and hoelite C(14)H(8)O(2), (natural 9,10-anthraquinone) display complex features. Raman microspectroscopy help to detect these phases non-destructively directly in the frame of rare samples. Investigated minerals are transformation products formed from gaseous phase originating in natural pyrolytical process occurring in the frame of coal heaps and coal series outcrops. It is recommended to include Raman spectroscopic characteristics of similar materials in databases for exobiological studies.
Subject(s)
Anthraquinones/chemistry , Coal , Minerals/chemistry , Phthalimides/chemistry , Spectrum Analysis, Raman , Spontaneous Combustion , Crystallization , Phase TransitionABSTRACT
The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.
Subject(s)
Computer-Aided Design , Cosmic Radiation , Extraterrestrial Environment , Linear Energy Transfer , Microbubbles , Models, Chemical , Thermoluminescent Dosimetry/instrumentation , Computer Simulation , Dose-Response Relationship, Radiation , Equipment Design , Equipment Failure Analysis , Materials Testing , Radiation Dosage , Reproducibility of Results , Sensitivity and Specificity , Surface Properties , Thermoluminescent Dosimetry/methodsABSTRACT
The PICASSO experiment investigates the presence and nature of dark matter in the Universe. The experiment is based on the detection of acoustic signals generated in explosive phase transitions induced by dark matter particles. This technique is an alternative more traditional detection technique like scintillation and ionisation, which are largely employed for dark matter search. One of the main advantages of this technique, besides its sensitivity to very low nuclear recoil energies (few keV), is its excellent background suppression features. A pilot experiment consisting of six superheated droplet detectors (40 g of active mass) is presently taking data at the Sudbury Neutrino Observatory (SNO) at a depth of 2000 m. We discuss the operation, calibration and data acquisition of the experiment and also the ongoing work to increase the sensitivity and the active mass of the detectors.
