14 research outputs found
The electron capture in Ho experiment â ECHo
Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the H ÎČ-decay and the Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide Ho. The maximum energy available for this decay, about 2.8âkeV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the Ho EC spectrum with energy resolution below 3âeV FWHM and with a time resolution below 1âÎŒs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure Ho samples, the identification and suppression of background sources as well as the precise parametrization of the Ho EC spectrum are of utmost importance. The high-energy resolution Ho spectra measured with the first MMC prototypes with ion-implanted Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1âkBq Ho will allow to reach a neutrino mass sensitivity below 10âeV/c. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1âMBq Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass
The Serial Link Processor for the Fast TracKer (FTK) at ATLAS
The Associative Memory (AM) system of the FTK processor has been designed to perform pattern matching using the hit information of the ATLAS silicon tracker. The AM is the heart of the FTK and it finds track candidates at low resolution that are seeds for a full resolution track fitting. To solve the very challenging data traffic problem inside the FTK, multiple designs and tests have been performed. The currently proposed solution is named the âSerial Link Processorâ and is based on an extremely powerful network of 2 Gb/s serial links. This paper reports on the design of the Serial Link Processor consisting of the AM chip, an ASIC designed and optimized to perform pattern matching, and two types of boards, the Local Associative Memory Board (LAMB), a mezzanine where the AM chips are mounted, and the Associative Memory Board (AMB), a 9U VME board which holds and exercises four LAMBs. We report also on the performance of a first prototype based on the use of a min@sic AM chip, a small but complete version of the final AM chip, built to test the new and fully serialized I/O. Also a dedicated LAMB prototype, named miniLAMB, with reduced functionalities, has been produced to test the mini@sic. The serialization of the AM chip I/O significantly simplified the LAMB design. We report on the tests and performance of the integrated system mini@sic, miniLAMB and AMB
The associative memory serial link processor for the fast TracKer (FTK) at ATLAS
The Fast TracKer (FTK) is an extremely powerful and very compact processing unit, essential for efficient Level 2 trigger selection in future high-energy physics experiments at the LHC. FTK employs Associative Memories (AM) to perform pattern recognition; input and output data are transmitted over serial links at 2 Gbit/s to reduce routing congestion at the board level. Prototypes of the AM chip and of the AM board have been manufactured and tested, in preparation of the imminent design of the final version
The electron capture in <sup>163</sup>Ho experiment â ECHo
Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3H ÎČ-decay and the 163Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163Ho. The maximum energy available for this decay, about 2.8âkeV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163Ho EC spectrum with energy resolution below 3âeV FWHM and with a time resolution below 1âÎŒs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163Ho EC spectrum are of utmost importance. The high-energy resolution 163Ho spectra measured with the first MMC prototypes with ion-implanted 163Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1âkBq 163Ho will allow to reach a neutrino mass sensitivity below 10âeV/c 2. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1âMBq 163Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass
The FTK: A Hardware Track Finder for the ATLAS Trigger
The ATLAS experiment trigger system is designed to reduce the event rate, at the LHC design luminosity of 1034 cm-2 s-1, from the nominal bunch crossing rate of 40 MHz to less than 1 kHz for permanent storage. During Run 1, the LHC has performed exceptionally well, routinely exceeding the design luminosity. From 2015 the LHC is due to operate with higher still luminosities. This will place a significant load on the High Level Trigger system, both due to the need for more sophisticated algorithms to reject background, and from the larger data volumes that will need to be processed. The Fast TracKer is a hardware upgrade for Run 2, consisting of a custom electronics system that will operate at the full rate for Level-1 accepted events of 100 kHz and provide high quality tracks at the beginning of processing in the High Level Trigger. This will perform track reconstruction using hardware with massive parallelism using associative memories and FPGAs. The availability of the full tracking information will enable robust trigger selection within the affordable latency available at the High Level Trigger, with only a limited degradation in performance arising from the additional pileup from higher luminosity running
Design of a hardware track finder (Fast Tracker) for the ATLAS trigger
International audienceThe use of tracking information at the trigger level in the LHC Run II period is crucial for the trigger and data acquisition system and will be even more so as contemporary collisions that occur at every bunch crossing will increase in Run III. The Fast TracKer is part of the ATLAS trigger upgrade project, it is a hardware processor that will provide every Level-1 accepted event (100 kHz) and within 100ÎŒs, full tracking information for tracks with momentum as low as 1 GeV . Providing fast, extensive access to tracking information, with resolution comparable to the offline reconstruction, FTK will help in precise detection of the primary and secondary vertices to ensure robust selections and improve the trigger performance