Recently, the all-optical Compton laser backscattering setup has become a promising approach in producing high-quality γ-rays. However, this method only produces a single γ-ray beam. In this paper, ...we report on the numerical study for the feasibility of producing double γ-ray beams using a 1 PW laser. Our method utilizes the all-optical setup with a structured solid target as a reflecting foil. The laser pulse is reflected by the foil after propagating a few millimeters into the underdense plasma. The reflected laser intensity is strongly boosted by the foil to invoke a radiation reaction as nonlinear Compton backscattering. Subsequently, the electron bunch traverses the foil, generating bremsstrahlung. Our simulation results show that a collimated γ-ray beam from the nonlinear Compton backscattering with the peak brilliance of 6.7 × 1020 photons/s/mm2/mrad2/0.1% BW at 15 MeV is produced. Another collimated γ-ray beam with the peak brilliance of 2.1 × 106 photons/s/mm2/mrad2/0.1% BW is produced by bremsstrahlung. The combined γ-ray beams act as a blaster and are of particular interest in nuclear interactions induced by high-energy photons.
Abstract
We present results of 2D particle-in-cell (PIC) simulations of carbon ion acceleration by 10 petawatt (PW) laser pulses, studying both circular polarized (CP) and linear polarized (LP) ...pulses. We carry out a thickness scanning of a solid carbon target to investigate the ideal thickness for carbon ion acceleration mechanisms using a 10 PW laser with an irradiance of 5 × 10
22
W cm
−2
. The energy spectra of carbon ions and electrons and their temperature are studied. Additionally, for the carbon ions, their angular divergence is studied. It is shown that the ideal thickness for the carbon acceleration is 120 nm and the cutoff energy for carbon ions is 5 and 3 GeV for CP and LP pulses, respectively. The corresponding carbon ions temperature is ~1 and ~0.75 GeV. On the other hand, the energy cutoff for the electrons is ~500 MeV with LP and ~400 MeV with CP laser pulses. We report that the breakout afterburner mechanism is most likely causing the acceleration of carbon ions to such high energies for the optimal target thickness.
Abstract
We report a dedicated setup built in-house for the annealing
of the HPGe clover detectors of the ELI-NP Array of DEtectors
(ELIADE) γ-ray spectrometer, as well as the post-annealing
testing ...of these detectors with the standard
60
Co &
152
Eu
radioactive calibration sources employing conventional analog
electronics. Both the design and assembly of the annealing setup
were performed at the Extreme Light Infrastructure — Nuclear
Physics (ELI-NP) facility, Măgurele, Romania. A `radiation
damage annealing assembly kit' (NRK-200 unit) from the detector
manufacturer Canberra is utilized in heating and controlling the
temperature of the Ge crystals of the annealed detector. The vacuum
inside the detector was maintained throughout the annealing process
by constantly pumping the system using a turbo-molecular pumping
station. The temperature of the germanium crystals, located inside a
vacuum sealed chamber, of the detector and the vacuum level of this
chamber were monitored throughout the annealing process, via both
in-person observation and remote (online) monitoring. The Graphic
User Interface (GUI) of an underlying LabVIEW script was utilized
for running the monitoring process of the temperature and vacuum
pressure values via a local network. To have the option of real-time
online monitoring of the temperature, vacuum pressure, we coupled
the web application Grafana with the Influx DB of the annealing
data, as well as the backup time information of an Uninterruptible
Power Supply (UPS) unit used in system.
New preshower detector for the DIRAC experiment Pentia, M.; Aogaki, S.; Dumitriu, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2015, Letnik:
795
Journal Article
Recenzirano
Odprti dostop
The Preshower (PSh) detector 1 is a component of the DIRAC setup 2. It is designed to identify and reject the huge e−e+ pairs background in the ππ and Kπ pairs measurement produced in a hadronic atom ...ionization process. In the high energy region used for kaon detection, the small Nitrogen Cherenkov detector has low electron rejection efficiency. To increase the overall efficiency, a new two-layer scintillator Preshower detector has been developed and built. The new Preshower–Cherenkov combination ensures an electron rejection efficiency better than 99% in the momentum range 1–7GeV/c.
The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π^{+}π^{-} atoms, produced by protons hitting a beryllium target. A part of these atoms ...crossed the gap of 96 mm between the target and a 2.1 μm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n_{A}^{L}=436_{-61}^{+157}|_{tot}, the lifetime of the 2p state is found to be τ_{2p}=(0.45_{-0.30}^{+1.08}|_{tot})×10^{-11} s, not contradicting the corresponding QED 2p state lifetime τ_{2p}^{QED}=1.17×10^{-11} s. This lifetime value is three orders of magnitude larger than our previously measured value of the π^{+}π^{-} atom ground state lifetime τ=(3.15_{-0.26}^{+0.28}|_{tot})×10^{-15} s. Further studies of long-lived π^{+}π^{-} atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.
We have performed the measurement of the 27Al(α, n) cross section at IFIN-HH for a range of energies from 2.5 to 5.2 MeV, using an array of 28 3He counters arranged in 3 concentric rings ...(ELIGANT-TN). Here we present the experimental setup and discuss the role of the 13C contamination which effects the measurements in the low-energy region. Energy-dispersive X-ray spectroscopy carried out before and after the experiment suggested an increase in the 13C concentration during the experiment.
After observing and investigating the double-exotic (a double-exotic atom is a bound system, in which both oppositely charged components are unstable particles like μ,π,K,…) π+π− atom with the ground ...state lifetime τ of about 3×10−15 s, the upgraded DIRAC experiment at the CERN PS accelerator observes for the first time long-lived states of the same atom with lifetimes of about 10−11 s and more. The number of characteristic pion pairs resulting from the breakup (ionisation) of long-lived π+π− atoms amounts to 436±61, corresponding to a signal-to-error ratio of better than 7 standard deviations. This observation opens a new possibility to measure energy differences between p and s atomic states and so to determine ππ scattering lengths.
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