Status of the caviar detector at LISE-GANIL

Spectromètre LISEInternational audienceIPhysics that motivated the building of the LISE magnetic spectrometer, main ideas exposed in the scientific council of GANIL June 4th 1981 by M. Brian and M. Fleury, were: atomic physics studies with stripped ions and the study of new isotopes produced by the fragmentation of beams. The LISE line is a doubly-achromatic spectrometer (angle and position), with a resolution better than 10-3. Since the first experiment performed in 1984, several improvements of the spectrometer were made: use of an achromatic degrader (1987, used for the first time in the world), building of the achromatic deviation and the Wien Filter (1990), building of a new selection dipole and associated vertical platform (1994), building of the new LISE2000 line (2001), use of the Caviar detector (2002), building of the CLIM target (2007). Despite an extreme international competition, the LISE spectrometer remains a world-leader equipment using more than 50 % and up to 90 % of the beam time available at GANIL. This paper presents the status of CAVIAR detector which consist of a MPWC dedicated to in flight particle position at the first dispersive plane of LISE. Since two years, intensive efforts were done with the objective to propose a 'plug and play' detector for nuclear physic experiments. We will describe the motivations and the system from MPWC up to the acquisition system. As example few experimental results will be presented

Supramolecular control of charge transport in molecular wires.

The transport of positive charges along porphyrin-based molecular wires has been probed in dilute solution using pulse radiolysis time-resolved microwave conductivity. The mobility of positive charges along isolated single-strand porphyrin wires was found to be 0.084 cm2/(V s). Addition of 4,4′-bipyridyl leads to the formation of a double-strand ladder complex, locking each polymer strand into a more planar structure and thus enhancing the porphyrin-porphyrin π-conjugation, leading to an increase in the charge carrier mobility by an order of magnitude to 0.91 cm2/(V s). Copyright © 2007 American Chemical Society

Role of amorphous and aggregate phases on field-induced exciton dissociation in a conjugated polymer

We have applied electric field assisted pump-probe spectroscopy in order to unravel the interplay of amorphous and aggregate phases on the polaron-pair photogeneration process in a conjugated porphyrin polymer. We find that excitons photogenerated in both phases are precursors for polaron pairs with different yields. Kinetic modeling indicates a substantially larger barrier for exciton dissociation in aggregates compared to amorphous areas. The majority of polaron pairs are however formed in aggregate phases due to efficient energy transfer from the amorphous phase. Based on the change in the Stark shift associated with the photogenerated polaron density, we provide a picture of the motion of polaron pairs under the external electric field. © 2013 American Physical Society

Digital Front-End Electronics for the Neutron Detector NEDA

19th Real Time Conference (RT) -- MAY 26-30, 2014 -- Nara, JAPANWOS: 000356458000029This paper presents the design of the NEDA (Neutron Detector Array) electronics, a first attempt to involve the use of digital electronics in large neutron detector arrays. Starting from the front-end modules attached to the PMTs (PhotoMultiplier Tubes) and ending up with the data processing workstations, a comprehensive electronic system capable of dealing with the acquisition and pre-processing of the neutron array is detailed. Among the electronic modules required, we emphasize the front-end analog processing, the digitalization, digital pre-processing and communications firmware, as well as the integration of the GTS (Global Trigger and Synchronization) system, already used successfully in AGATA (Advanced Gamma Tracking Array). The NEDA array will be available for measurements in 2016.Osaka Univ, Res Nucl PhysGeneralitat Valenciana, Spain [PROMETEO/2010/101]; INFN, Italy; Spanish MINECO [AIC-D-2011-0746, FPA2011-29854, FPA2012-33650]; Swedish Research Council; Scientific and Technological Research Council of Turkey (TUBITAK); UK STFC; Science and Technology Facilities Council [ST/J000124/1, ST/L005735/1, ST/L005727/1]This work was supported by the Generalitat Valenciana, Spain, under grant PROMETEO/2010/101. Some authors were supported in part by INFN, Italy, and by the Spanish MINECO under grants AIC-D-2011-0746, FPA2011-29854, and FPA2012-33650. The Swedish Research Council, the Scientific and Technological Research Council of Turkey (TUBITAK), and the UK STFC also provided support

AGATA phase 2 advancements in front-end electronics

The AGATA collaboration has a long-standing leadership in the development of front-end electronics for high resolution γ -ray spectroscopy using large volume high purity germanium detectors. For two decades, the AGATA collaboration has been developing state-of-the-art digital electronics processing with high resolution sampling ADC, high-speed signal transfer and fast readout to a high throughput computing (HTC) farm for on-line pulse shape analysis. The collaboration is presently addressing the next challenge of equipping a 4 π array with more than 6000 channels in high resolution mode, generating approximately 10 MHz of total trigger requests, coupled to a large variety of complementary instruments. A next generation of front-end electronics, presently under design, is based on industrial products (System on Module FPGA’s), has higher integration and lower power consumption. In this contribution, the conceptual design of the new electronics is presented. The results of the very first tests of the pre-production electronics are presented as well as future perspectives.ISSN:1434-6001ISSN:1434-601

Design and Test of a High-speed Flash ADC Mezzanine Card for High-resolution and Timing Performance in Nuclear Structure Experiments

International audienceThis board will be part of the upgrade for the new electronics for the EXOGAM2 (HP-Ge detector array) and NEDA (BC501A-based neutron detector array), therefore it was necessary to deal with the problem of providing a sampling card with high resolution for new gamma spectroscopy experiments while sampling at very high rates, with a broad bandwidth in order to preserve the shape for further analysis. Pulse shape analysis is of paramount importance in neutron detectors, such as NEDA, based on scintillators that are sensitive to γ-rays as well. High resolution and high speed are often two parameters which conform a trade-off and it is hard to achieve both simultaneously. The aforementioned constraints and the urge of building new sampling electronics to improve the signal analysis in nuclear physics experiments, led to the development of this FADC mezzanine This involves sampling rates up to 250 Msps preserving a high resolution of 11.3 effective bits in order to satisfy the experiment demands. In this work is described the design and the test bench proposed for a proper high speed ADC characterization system and the results obtained up to now

MUST II: Large solid angle light charged particle telescope for studies with radioactive beams

International audienceA large area telescope for measurements with radioactive beams in inverse kinematics for transfer reactions or unbound final states is described. The performance and the first beam tests results are described

AGATA phase 2 advancements in front-end electronics

International audienceThe AGATA collaboration has a long-standing leadership in the development of front-end electronics for high resolution $\gamma$-ray spectroscopy using large volume high purity germanium detectors. For two decades, the AGATA collaboration has been developing state-of-the-art digital electronics processing with high resolution sampling ADC, high-speed signal transfer and fast readout to a high throughput computing (HTC) farm for on-line pulse shape analysis. The collaboration is presently addressing the next challenge of equipping a 4$\pi$ array with more than 6000 channels in high resolution mode, generating approximately 10 MHz of total trigger requests, coupled to a large variety of complementary instruments. A next generation of front-end electronics, presently under design, is based on industrial products (System on Module FPGA’s), has higher integration and lower power consumption. In this contribution, the conceptual design of the new electronics is presented. The results of the very first tests of the pre-production electronics are presented as well as future perspectives