A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8×106 positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼250  GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena

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We have measured the radiation tolerance of poly-crystalline and single-crystalline diamonds grown by the chemical vapor deposition (CVD) process by measuring the charge collected before and after irradiation in a 50 m pitch strip detector fabricated on each diamond sample. We irradiated one group of sensors with 800 MeV protons, and a second group of sensors with 24 GeV protons, in steps, to protons cm−2 and protons cm−2 respectively. We observe the sum of mean drift paths for electrons and holes for both poly-crystalline CVD diamond and single-crystalline CVD diamond decreases with irradiation fluence from its initial value according to a simple damage curve characterized by a damage constant for each irradiation energy and the irradiation fluence. We find for each irradiation energy the damage constant, for poly-crystalline CVD diamond to be the same within statistical errors as the damage constant for single-crystalline CVD diamond. We find the damage constant for diamond irradiated with 24 GeV protons to be and the damage constant for diamond irradiated with 800 MeV protons to be . Moreover, we observe the pulse height decreases with fluence for poly-crystalline CVD material and within statistical errors does not change with fluence for single-crystalline CVD material for both 24 GeV proton irradiation and 800 MeV proton irradiation. Finally, we have measured the uniformity of each sample as a function of fluence and observed that for poly-crystalline CVD diamond the samples become more uniform with fluence while for single-crystalline CVD diamond the uniformity does not change with fluence.

In order to fully exploit the ballistic potential of particle therapy, we propose an online range monitoring concept based on time-of-flight (TOF)-resolved prompt gamma (PG) detection in a single proton counting regime. In a proof of principle experiment, different types of monolithic scintillating gamma detectors are read in time coincidence with a diamond-based beam hodoscope, in order to build TOF spectra of PG generated in a target presenting an air cavity of variable thickness. Since the measurement was carried out at low beam currents (< 1 proton/bunch) it was possible to reach excellent coincidence time resolutions, of the order of 100 ps (σ). Our goal is to detect possible deviations of the proton range with respect to treatment planning within a few intense irradiation spots at the beginning of the session and then carry on the treatment at standard beam currents. The measurements were limited to 10 mm proton range shift. A Monte Carlo simulation study reproducing the experiment has shown that a 3 mm shift can be detected at 2σ by a single detector of ∼1.4 × 10−3 absolute detection efficiency within a single irradiation spot (∼108 protons) and an optimised experimental set-up.

A prototype of digital frequency multiplexing electronics allowing the real time monitoring of microwave kinetic inductance detector (MKIDs) arrays for mm-wave astronomy has been developed. Thanks to the frequency multiplexing, it can monitor simultaneously 400 pixels over a 500 MHz bandwidth and requires only two coaxial cables for instrumenting such a large array. The chosen solution and the performances achieved are presented in this paper.the analog bandwidth and the number of detectors (resonators) managed by the electronics must be maximized. At this respect, we present here a building block for the NIKA camera [1,2] that is able to monitor simultaneously 400 pixels over a 500 MHz bandwidth. Instrumentation methodologyThe instrumentation setup used for NIKA and its associated electronics is extensively described in [9]. In summary, the excitation frequency comb is generated at baseband in the electronics using coordinate rotation digital computer (CORDIC), up-converted with an IQ mixer to the 1 to 10 GHz frequency and injected in the resonator line. The returning and thus modified frequency comb is down-converted and analyzed by channelized Digital Down Converters (DDC) to determine each tone amplitude and phase. Aside from good signal to noise ratio (SNR) on the whole chain, the first limitation on the number of MKIDs managed by this solution is given by the digital to analog converter (DAC) and the analog to digital converter (ADC) bandwidths. The second constraint comes from the computing power limitation. For a FPGA (Field Programmable Gate Array), the computational power is determined by the available amount user logic and multiplier block times their maximum running frequency. Indeed, thanks to the inherently achievable parallelization in FPGAs, this figure is much larger compared to DSPs that have only a few Multiplier Accumulators.Starting from the previous version, which was able to manage a line of 128 tones over a bandwidth of 125 MHz, three solutions are possible to increase the multiplexing factor per line. The first solution would be to juxtapose several of the previous electronic boards, each one managing its share of bandwidth, see figure 1.Unfortunately, the analog filters required to separate each share of bandwidth before downconverting have such a stringent separation requirement to avoid crosstalk due to image frequencies that they cannot be constructed.The second option is to use faster ADCs an DACs combined to a larger computing power (FPGA) in order to directly cover a larger bandwidth. Following this path, two concurrent approaches still remain. The first "obvious" solution is to directly generate the frequency comb at twice the desired bandwidth and to perform channelized DDC with the ADC signal. Unfortunately, due to the frequency limitation of state of the art FPGAs this can only be achieved by performing massive design pipelining on both sides, excitation and analysis, and therefore makes it extremely complicated.The third option, which we have chosen, is to use modern DACs feat...