Search

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

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

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