We report on the first analysis of directed and elliptic flow with the new method of Lee-Yang zeroes. Experimental data are presented for Ru+Ru reactions at 1.69A GeV measured with the FOPI detector at SIS/GSI. The results obtained with several methods, based on the event-plane reconstruction, on Lee-Yang zeroes, and on multi-particle cumulants (up to 5th order) applied for the first time at SIS energies, are compared. They show conclusive evidence that azimuthal correlations between nucleons and composite particles at this energy are largely dominated by anisotropic flow. The study of collective flow in relativistic heavy ion reactions is of great interest since it is expected to shed light on our knowledge about the properties of hot and dense nuclear matter and the underlying equation of state (EoS) [1]. As pointed out early on, nuclear collective flow is also influenced by the momentum-dependent interactions and the in-medium nucleon-nucleon cross section [2,3]. Both effects play a crucial role in the determination of the EoS and cannot be neglected at intermediate energies. In this regard both directed and elliptic flow are a field of intense experimental and theoretical researches (see [4] and references therein).Most flow analyses, based either on the reaction plane reconstruction (the so-called event-plane method) [5] or on two-particle azimuthal correlations [6] rely on the assumption that the only correlations are those stemming from the existence of the reaction plane. Other correlations (usually called non-flow), such as small-angle correlations due to final state interactions and quantum sta- * Electronic address: nicole.bastid@clermont.in2p3.fr tistical effects [7], correlations due to resonance decays [8] and mini-jet production [9] are neglected. In recent years, several alternative techniques were introduced, in which non-flow correlations can be unraveled. The cumulant method is based on a cumulant expansion of multiparticle (typically four particles) correlations [10], which eliminates most of non-flow correlations. It has been applied at ultra-relativistic energies, at RHIC and SPS for directed and elliptic flow studies and also for higher harmonic measurements [11,12,13,14,15]. More recently, a new method based on an analogy with the Lee-Yang theory of phase transitions [16], where flow is extracted directly from the genuine correlation between a large number of particles, has been proposed [17,18,19]. This method is expected to provide the cleanest separation between flow and non-flow effects.We present the first analysis of collective flow using the new method of Lee-Yang zeroes. The cumulant method is also applied, for the first time at SIS energies. A comparison with results obtained with the event-plane method is performed. We are thus able to check for the first time the validity of standard methods at SIS energies, by investigating possible contributions of correla-

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The effect of enhanced filtration on protection citizens staying indoor against airborne radionuclides released during nuclear core melt accidents was determined by field measurements using outdoor particles as simulants. An electrically enhanced filter was installed in the HVAC system of an office building and its removal efficiency for particles was altered by using a separate particle charging section in power on and off positions. The effect of air filtration on indoor particle concentrations was determined by using an automated measurement system which was continuously sampling from the outdoor air, filtered supply air and exhaust air. With the aid of the measured outdoor and modelled indoor concentrations the indoor/outdoor ratio of particles of outdoor origin could be accurately determined. External charging of the particles increased the electret filters removal efficiency for 0.4 µrn size particles from 60% to 95%, resulting in decrease of the average I/O ratio of the same size particles from 0.67 to 0.40. Despite the high improvement in the supply air filtration efficiency the indoor concentrations decreased only modestly which is likely due to the leaky construction of the building, demonstrating the detrimental effect of air infiltration on the protection provided by buildings against outdoor airborne hazards. Practical implications: The developed method allows quantification of the key parameters affecting the protection of buildings against outdoor contaminants, thus allowing accurate estimation of size resolved indoor to outdoor ratios for fine particles. The electrically enhanced filter can remove effectively also submicron particles thus reducing the occupant exposure to outdoor hazardous or harmful materials. Best results can be achieved with airtight buildings.

Aim: The aim of this paper is to present the results of an experiment which was conducted as a part of the "End-user driven DEmo for cbrNe" (EDEN) project on the 17th and 18th of May 2016 in the Chernobyl Exclusion Zone, and more precisely in Pripyat. Introduction: One of the main requirements for highly effective emergency exercise is a well prepared and reliable scenario which is executed in conditions that closely resemble reality. This requirement brings even more value if the exercise is tailored to build response capacity for CBRNE hazards. First responders' skills and work experience in contaminated areas are desirable response capacity of emergency units. However, because CBRNE emergencies are low-probability, high-impact events, they are very rarely happening. Therefore, building this response capacity definitely requires exercising, at least in a simulated environment. Simulating CBRNE hazards, and especially biological and radiological ones, is very challenging, expensive, time-consuming, strictly regulated and in many cases, like for nuclear, almost impossible. However, there is one more option, apart from simulating the contamination. It is exercising in contaminated areas like e.g. in the Chernobyl Exclusion Zone. To organise this type of exercise requires from the exercise planners and organizers a deep understanding of the hazard as such. Since the hazard constitutes a realistic risk of negative impact on the exercise participants' health, such events have to be planned and prepared in detail, and with an appropriate consideration given to the risk level in order to minimize it. An increased level of first responders' readiness built upon such exercises is definitely an operational value. However, it is questioned how high could be the cost of this benefit on the participants health, if any? What are the key aspects to be considered while organising an emergency exercise in a radioactively contaminated training site in order to minimize health and other risks? What type of training and operational benefits could be identified when working in such an environment? Methodology: The paper analyses the CBRNE exercise executed in Pripyat presenting a lesson learnt which could easily be utilised by the future planners and organisers of such type of exercises. Conclusions: The experiment proved that providing a safety plan for such an exercise and its proper implementation allows the exercise to be executed in a manner which ensures that the safety levels regulated by law are not exceeded. Exercising in contaminated zones provides an excellent opportunity for the improvement of individual skills and coping capacity of the entire CBRNE system, including standard operating procedures. It is important to note that during well organized and controlled exercises, the risk for health and life of the first responders due to radioactive contamination and exposure is negligible.

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