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The paper describes a new E-Delta-E detection module which includes a position-sensitive double-sided strip detector (DSSD) and a low-pressure pentane-filled Delta-E chamber for detection of Evaporation Residues (ER) in complete fusion nuclear reactions. The goal is to synthesize superheavy isotopes at the new DC-280 (Dubna Cyclotron) cyclotron of the Joint Institute for Nuclear Research (JINR). With the 48Ca ion beam intensity of about 5-7 pmcA (particle micro ampere) and the Delta-E counter count rate of approximately 1.0E+4 sec-1, we observe a decrease in the overall registration efficiency of the gas Delta-E counter. The paper proposes a solution to this problem: introduction of an additional negatively biased electrode, which results in the stabilization of the Delta-E detector operation., Comment: The Dubna Gas-Filled Recoil Separator-2

In this paper we report on the reasonable nature of sharing signals measured with large area DSSD detectors. This detector manufactured by Micron Semiconductor (UK) and in use at the DGFRS-2 setup installed at DC-280 ultra intense cyclotron of FLNR, JINR. Some results from other setups are presented. We believe that pitch value as well as threshold value play dominant role in the charge sharing process. Some other parameters influenced by that process are considered in brief too, but sometimes in semi-quantity form.

A simple routine is proposed for monitoring the efficiency value of a low pressure pentane filled multi-wire proportional chamber (MWPC) in long term experiments. The proposed algorithm utilizes a two parameter approximation for the background function. It is based on a linear approximation of the background in the energy range of 4.8 to 10.0 MeV and an exponential approximation of the neutron induced tail in the 1.5 to 4.2 MeV region. This specific energy interval is used to measure the efficiency value. Prior to discussing the algorithm, a description of the DGFRS-2 setup detection module is provided. Additionally, an example of its application is presented for the complete fusion of a heavy ion induced 232Th+48Ca = Ds complete fusion nuclear reaction. Descriptions of two other two-parameter functional dependencies for background approximations are also provided. A feature of this algorithm is that there is no interruption of the main experiment for a calibration test (reaction). An alternative scenario is considered in brief too. In consist of a measurement of scattered target like ions in 30 to 45 MeV energy interval to estimate an efficiency value., Comment: For high projectile intensities

In this paper, we present the results of the first beam tests of the detection system at the focal plane of the Dubna Gas-Filled Recoil Separator-2 (DGFRS-2), which receives beams from the DC-280 FLNR cyclotron. The high beam intensity of $^{48}$Ca$^{+10}$ heavy ions from the cyclotron enables us to obtain a number of superheavy recoils sufficient to compare both the measured and calculated spectra of superheavy recoils implanted into a silicon detector. A real-time algorithm to search for an Evaporation Residue (ER) -- $\alpha$ correlated sequences is described in brief. It should be noted that the DGFRS-2 spectrometer operates in conjunction with the 48x128 strip DSSD (Double-sided Silicon Strip Detector; 48x226 mm2) detector and a low-pressure pentane-filled gaseous detector (1.2 Torr; 80x230 mm$^2$). A block-diagram of the spectrometer and the event format are also presented. Special attention is paid to the response of a low-pressure pentane-filled DeltaE multiwire proportional chamber for recoils of Fl, synthesized in the $^{242}$Pu+$^{48}$Ca $\to$ $^{287}$Fl +3n complete fusion nuclear reaction. Some actual parameters of the detection system have also been extracted from $^{\rm nat}$Yb + $^{48}$Ca, $^{232}$Th + $^{48}$Ca, $^{243}$Am + $^{48}$Ca, $^{238}$U + $^{48}$Ca reactions. The effect of neighbor strip charge sharing for the ohmic side of the DSSD detector is also under consideration., Comment: 18 pages

A new wide-range formula $T_\alpha =f (Q_\alpha)$ to operate with the new DGFRS2 analog spectrometer installed at the DC-280 cyclotron facility is presented. The main goal of this formula application algorithm is to search the optimal time correlation recoil-alpha parameter directly during the execution of the C++ acquisition code. Note that the spectrometer operates together with the 48x128 strip DSSD (Double Side Strip Detector) detector and low-pressure pentane-filled gaseous detector. Comparison with others known formulas is performed for Z=119,120 nuclei., Comment: will replace with more correct data (Table1) in a nearest future

Detection system and software package coded in Builder C ++ are developed for the new analog spectrometer of the DGFRS-2 setup installed on the new DC-280 cyclotron. This software allows providing data acquisition using a 48x128 DSSSD (Double Side Silicon Strip Detector) detector and a multi-wire gaseous detector. The main feature of this software package is the use of flexible real-time algorithms to provide deep suppression of the background in reactions for the synthesis of superheavy elements, using the detection of correlations ER-{\alpha} (Recoil-alpha particle). The block-diagram of analog spectrometer is presented., Comment: Develomments at new gas filled separator of JINR(FLNR)

The Dubna Gas Filled Recoil Separator is the most advanced facility currently in use in the field of research of superheavy nuclei. Definitely, the DGFRS detection system and method of active correlations have played a significant role in these discoveries. Author defines abstract mathematical objects, like correlation graph and incoming event matrixes of a different nature in order to construct a simple procedure for detecting rare events, yet more exhaustive compared to the present one, using real time detection mode. In this case one can use any of correlation graph links to trigger cyclotron beam stopper to provide background free conditions to search for ultra rare alpha decays. Schematics of these algorithms are presented.

Recently, in the DGFRS related experiments the discoveries of new superheavy elements 114 to 118 were successfully performed. As concerns to a background radical suppression in those experiments it was namely Active correlations method which was applied to this goal. Note, that application of DSSSD detector allows one to apply this method more effectively, although with some difficulties due to neighbor strips edge effects. Present version of the DGFRS spectrometer is presented. Shapes of ER registered energy spectra in the nat Yb+48Ca reaction are presented. First results of its application in the 240Pu+48Ca=Fl complete fusion nuclear reaction are presented too. Conclusion, that edge effects are to a first approximation explained by the role of inter strips area is drawn., Comment: arXiv admin note: text overlap with arXiv:1607.05270

New approach to the life time estimation for recoil alpha detected times is presented. Brief description of the Dubna Gas Filled Recoil Separator detection module is presented too. This approach will be used for real time detecting ctive correlationsmethod with nearest future commissioning of new FLNR DC280 extremely high intense heavy ion cyclotron in the year 2017., Comment: Utra high heaavy ion beam intensity cyclotron. Application of active correlations method

A new approach to provide a fruitful analysis of signal amplitude is proposed. It is this method that has made it possible to eliminate some observed artificial events from the list of candidates for decays of superheavy nuclei. Examples of estimates of measured amplitudes of evaporation residues (EVR) are presented. Some attention is paid to a new hard statistical criterion for detecting rare events. This criterion can be applied in the case of significant role of random factors.

Sources of non-linear response of PIPS detector, when detecting highly ionizing particles like recoils (EVR), fission fragments and heavy ions, including formation of large pulse-height defect (PHD) are considered. An analytical formula to calculate the recombination component of EVR PHD is proposed on the base of surface recombination model with some empirical correction. PC-based simulation code for generating the spectrum of the measured recoil signal amplitudes of the heavy implanted nuclei is presented. The simulated spectra are compared with the experimental ones for the different facilities: the Dubna Gas Filled Recoil Separator (DGFRS), SHIP and RIKEN gas-filled separator. After the short reviewing of the detection system of the DGFRS, is considered the real-time matrix algorithm application aimed to the radical background suppression in the complete-fusion heavy-ion induced nuclear reactions. Typical examples of application in the long term experiments aimed to the synthesis of superheavy elements Z=112-118 are presented [1-9]., Comment: Pulse height defect in Si detectors, charge multiplication effect

First test of the 4pi detector for study of exponential law of radioactive decay and possibility of observation of Zeno effect [1-3], measuring the mean life of 216Po is presented. This detector consists of two surface-barrier n-Si(Au) detectors placed in the close contact ( <1mm) to each other. Th foil is used as a generator of Rn- gas. The foil was covered by nuclear filter with 0.4 mm pores and placed in the bottom of vacuum chamber. So, direct alpha-particles can not reach the detector active surface. The measured half-live of 216Po of 143.5 (0.6) ms is in agreement with literature sources. It is shown, that for the definite source the random background correlation counts are mostly caused by the 220Rn - 216Po alpha activities and that it is not an easy task to decrease a background level of units of percents in the time region >4T1/2. Both, the data acquisition system and the vacuum chamber design are presented in brief.

New detection system design for heavy element research with 48Ca projectile has been reported. This system is based on application of 32 position sensitive strip PIPS detector and low pressure pentane filled TOF detector application in 48Ca induced nuclear reactions. To suppress beam associated background products new version of real time method of active correlations has been applied. Examples of applications in 249Bk+48Ca and 243Am+48Ca reactions are presented. The system development to operate together with the digital ORNL detection system to provide a quick search for recoil to alpha correlation chains has been discussed too., Comment: 2013 Varna

A complex analysis has been performed on the energy amplitude signals corresponding to events of Z=117 element measured in the 249Bk+48Ca complete fusion nuclear reaction. These signals were detected with PIPS position sensitive detector. The significant values of pulse height defect both for recoils (ER) and fission fragments (FF) were measured. Comparison with the computer simulations and empirical formulae has been performed both for ER and FF signals., Comment: Implanted nuclei decay

PC-based one-crate monitoring and control system of the Dubna Gas Filled Recoil Separator (DGFRS) is considered. It is developed for the long-term experiments at the U400 FLNR cyclotron and is aimed at the synthesis of super heavy nuclei in heavy ion induced complete fusion reactions. Parameters related to: a) beam and cyclotron; b) separator by itself, c) detection system, d) target and entrance window are measured and stored in the protocol file of the experiment. Special attention is paid to generating the alarm signals and implementing further the appropriate procedures, Comment: parameter monitoring C++ code

The purpose of the paper is the development of the formalism for the treatment of rare events especially, when one applies active correlation method to suppress background products in the heavy ion induced complete fusion nuclear reactions. This formalism in fact is an extension of classical background signal combinations formalism for the case of time multi intervals., Comment: Rare decay statistics experiments

Two decay chains originated from the even-even isotope 294118 produced in the 3n-evaporation channel of the 249Cf+48Ca reaction. Method of active correlations is applied to suppress backgrounds associated with the cyclotron. It is planned to apply this technique for the forthcoming experiment aimed to the synthesis of Z=120 element. A calibration dependence for a recoil measured energy signal is presented as well as a computer simulation spectrum for Z=118 nuclei.

REal-time Detection and STORage of Multy-chain events Builder C++ code has been designed to operate together with the new DGFRS detection system in FLNR, JINR. It allows to provide event by event storage and real-time search for ER-alpha sequences both for 32 strip position sensitive PIPS detector (CANBERRA NV) or 48x128 strip DSSSD detector (Micron Semiconductors). In the last case it operates in parallel with the ORNL digital system. Namely with this code (PIPS detector branch) it has become possible to detect 13 decay chains of Z=117 nuclei in the reaction 249Bk+48Ca-> 117+3,4n., Comment: NEC 2013

General philosophy of procedure of detecting rare events in the recent experiments with 48Ca projectile at the Dubna Gas-Filled Recoil Separator(DGFRS) aimed to the synthesis of superheavy elements (SHE) has been reviewed. Specific instruments and methods are under consideration. Some historical sources of the successful experiments for Z=112-118 are considered too. Special attention is paid to application of method of active correlations in heavy-ion induced complete fusion nuclear reactions. Example of application in Z=115 experiment is presented. Brief description of the 243Am + 48Ca -> 291-x115+xn experiment is presented too. Some attention is paid to the role of chemical experiments in discoveries of SHEs. The DGFRS detection/monitoring system is presented in full firstly.

A RAD C++ Builder's 6.0 code CEDV under Windows XP has been designed for visualizing data obtained from heavy-ion-induced complete fusion reactions at the main U-400 cyclotron of FLNR. The main purpose of the code is processing the data from the experiments aimed to at studying chemical properties of SHE. Data from the Dubna Gas -Filled Recoil Separator could be processed too. Some subroutines for estimating statistical parameter are also presented ; these are based on modified BSC (background signal combination) approaches.

With reaching to extremely high intensities of heavy-ion beams new requirements for the detection system of the Dubna Gas-Filled Recoil Separator (DGFRS) will definitely be set. One of the challenges is how to apply the active correlations method to suppress beam associated background products without significant losses in the whole long-term experiment efficiency value. Different scenarios and equations to develop the method according this requirement are under consideration in the present paper. The execution time to estimate the dead time parameter associated with the optimal choice of the life-time parameter is presented., Comment: in print for Lett. to ECHAYA 2015

LDSC (Linked decay signal combination) is modified taking into account application of active correlation technique to suppress beam associated backgrounds. Examples of application are presented.

Real-time PC based algorithm is developed for DSSSD ( Double Side Silicon Strip Detector) detector. Brief description of the detection system is also presented. Complete fusion nuclear reaction natYb+48Ca->217Th is used to test this algorithm at 48Ca beam. Example of successful application of a former algorithm for resistive strip PIPS detector is presented too., Comment: EVR-alpha correlation sequence real-time search. PACS:07.05.Wr, Dubna 2015

Application of real-time matrix algorithm in heavy ion induced complete fusion nuclear reactions of superheavy elements synthesis is reviewed in brief. An extended algorithm, for the case of the recoil detection efficiency is not close to 100% has been proposed., Comment: EVR-alpha or/and alpha-alpha correlations search

A new real-time PC based algorithm and a compact C++ code to operate in a real-time mode with a 48x128 strip double side position sensitive large area silicon radiation detector Micron Semiconductors (UK) are developed and tested. Namely with this new approach it has become possible to provide the quick extraction of EVR-alpha correlated sequences in heavy ion induced complete fusion nuclear reactions. Specific attention is paid to the application of new CAMAC 4 M modules for charge particle position measurement during long- term experiments aimed to the synthesis of new superheavy nuclei. Some attention is paid to the different (combined) algorithm scenario to search for ER-alpha and alpha-alpha chains., Comment: Method for radical background suppression