Proton-induced Radiation Damage Research Articles

Study on scintillation properties and proton-induced radiation damage of LaCl[formula omitted] crystals

A Cs2LiYCl6 (CLYC) scintillation crystal is a promising candidate for fast neutron spectroscopy due to its dual mode gamma/neutron capability and good energy resolution. Despite promising features, CLYC’s limited radiation tolerance and inability to separate alpha/proton particles using pulse shape discrimination (PSD) method restrict its applicability in fast neutron spectroscopy. The significant cross-sections for 35Cl(n,p)35S and 35Cl(n, α)32P reactions make 35Cl-containing crystals attractive candidates for fast neutron detection, prompting their development as a promising new solution. This study reports the growth of LaCl3 crystals via the Bridgman technique, enabling further exploration of their scintillation and material properties for fast neutron detection applications. The effects of the proton irradiation on LaCl3 crystals were investigated by irradiating them with a 100 MeV proton beam at the Korea Multi-purpose Accelerator Complex. The study quantified radiation damage by comparing the pre- and post-irradiation scintillation properties and PSD of the LaCl3 crystals. The results of the measurements demonstrate that LaCl3 crystals are promising candidates for applications in fast neutron identification, spectroscopy, and space mission, maintaining performance even under high-radiation environments.

Proton-induced radiation damage in Cs2LiYCl6:Ce scintillator

Cs2LiYCl6:Ce crystal scintillator (CLYC:Ce) has garnered significant attention for its applications in both neutron detection and gamma-ray spectroscopy. This is due to its excellent pulse shape discrimination (PSD) capabilities, which allow for distinguishing between neutrons and gamma rays. Recently, there has been interest in utilizing CLYC:Ce in high-dose environments, making it crucial to understand the effects of radiation damage on its performance. In this work, we aim to examine the impact of radiation damage on the scintillation performance of CLYC:Ce under 100 MeV proton beam. To minimize systematic uncertainty, the change in light output of CLYC:Ce was measured at different accumulated doses using the same experimental setup. The pulse shape discrimination for thermal neutrons was assessed before and after irradiation. Additionally, the decay time of gamma-ray and thermal neutron-induced pulses was analyzed at various accumulated doses. The results of these analyses provide support for little degradation of pulse shape discrimination even with the high proton dose. Furthermore, the study considered and discussed the scintillation recovery of CLYC:Ce over a month. Despite the substantial damage induced by high-energy protons, the results demonstrate that CLYC:Ce remains a promising scintillator for thermal neutron detection.

Radiation damage of [formula omitted] pixelated CdZnTe due to high-energy protons

Pixelated CdZnTe detectors are a promising imaging-spectrometer for gamma-ray astrophysics due to their combination of relatively high energy resolution with room temperature operation negating the need for cryogenic cooling. This reduces the size, weight, and power requirements for telescope-based radiation detectors. Nevertheless, operating CdZnTe in orbit will expose it to the harsh radiation environment of space. This work, therefore, studies the effects of 61MeV protons on 2×2×1cm3 pixelated CdZnTe and quantifies proton-induced radiation damage of fluences up to 2.6×108p/cm2. In addition, we studied the effects of irradiation on two separate instruments: one was biased and operational during irradiation while the other remained unbiased. Following final irradiation, the 662keV centroid and nominal 1% resolution of the detectors were degraded to 642.7keV,4.9%(FWHM) and 653.8keV,1.75%(FWHM) for the biased and unbiased systems respectively. We therefore observe a possible bias dependency on proton-induced radiation damage in CdZnTe. This work also reports on the resulting activation and recovery of the instrument following room temperature and 60°C annealing.

Effects of proton-induced radiation damage on CLYC and CLLBC performance

Cerium-doped Cs$_2$LiYCl$_6$ (CLYC) and Cs$_2$LiLaBr$_x$Cl$_{6-x}$ (CLLBC) are scintillators in the elpasolite family that are attractive options for resource-constrained applications due to their ability to detect both gamma rays and neutrons within a single volume. Space-based detectors are one such application, however, the radiation environment in space can over time damage the crystal structure of the elpasolites, leading to degraded performance. We have exposed 4 samples each of CLYC and CLLBC to 800 MeV protons at the Los Alamos Neutron Science Center. The samples were irradiated with a total number of protons of 1.3$\times$10$^{9}$, 1.3$\times$10$^{10}$, 5.2$\times$10$^{10}$, and 1.3$\times$10$^{11}$, corresponding to estimated doses of 0.14, 1.46, 5.82, and 14.6 kRad, respectively on the CLYC samples and 0.14, 1.38, 5.52, and 13.8 kRad, respectively on the CLLBC samples. We report the impact these radiation doses have on the light output, activation, gamma-ray energy resolution, pulse shapes, and pulse-shape discrimination figure of merit for CLYC and CLLBC.

FT-IR measurement on the damage of Japanese paper induced by PIXE analysis

Analysis of cultural heritage samples by PIXE involves the risk of damaging precious samples due to MeV-proton irradiation. To investigate appropriate methods to detect invisible damage due to PIXE analysis, we analyzed the change in chemical bonding of the sample surface subjected to PIXE and RBS measurement by Fourier Transform InfraRed spectroscopy (FT-IR). We used Japanese hemp paper as a simulated cultural property sample. The proton irradiation for the PIXE/RBS measurement was performed in a vacuum with an incident beam energy of 2.5 MeV, a beam current of 1 nA, and an irradiation time up to 10 min. The corresponding beam flux and fluence were 0.06 nA/mm2 and 4 [Formula: see text]Coulomb/cm2, respectively. When the irradiation time was 10 min, the absorbed dose was 480 kGy on the sample surface. We identified neither change of elemental composition nor visible change such as discoloration due to irradiation. However, we found changes in peak heights in the measured FT-IR spectra, which suggest the destruction of chemical bonds such as O–H and C–O due to proton-induced radiation damage.

Proton-Induced Radiation Damage in BaF2, LYSO, and PWO Crystal Scintillators

Future high-energy physics experiments at the energy and intensity frontiers will face a challenge of severe radiation environment from both ionization dose and charged and neutral hadrons. The high-luminosity large hadron collider, for example, will present an environment, where up to 130 Mrad ionization dose, $3 \times 10^{14}$ charged hadrons/cm2 and $5 \times 10^{15}$ neutrons/cm2 are expected. In this paper, we report our investigation on charged hadron-induced radiation damage in BaF2, LYSO/LFS, and PWO crystals up to $3 \times 10^{15}$ protons/cm2 by using 800-MeV protons at the Los Alamos Neutron Science Center. Comparison is made between radiation damages induced by protons and ionization dose alone.

High energy proton induced radiation damage of rare earth permanent magnet quadrupoles.

Permanent magnet quadrupoles (PMQs) are an alternative to common electromagnetic quadrupoles especially for fixed rigidity beam transport scenarios at particle accelerators. Using those magnets for experimental setups can result in certain scenarios, in which a PMQ itself may be exposed to a large amount of primary and secondary particles with a broad energy spectrum, interacting with the magnetic material and affecting its magnetic properties. One specific scenario is proton microscopy, where a proton beam traverses an object and a collimator in which a part of the beam is scattered and deflected into PMQs used as part of a diagnostic system. During the commissioning of the PRIOR (Proton Microscope for Facility for Antiproton and Ion Research) high energy proton microscope facility prototype at Gesellschaft für Schwerionenforschung in 2014, a significant reduction of the image quality was observed which was partially attributed to the demagnetization of the used PMQ lenses and the corresponding decrease of the field quality. In order to study this phenomenon, Monte Carlo simulations were carried out and spare units manufactured from the same magnetic material-single wedges and a fully assembled PMQ module-were deliberately irradiated by a 3.6 GeV intense proton beam. The performed investigations have shown that in proton radiography applications the above described scattering may result in a high irradiation dose in the PMQ magnets. This did not only decrease the overall magnetic strength of the PMQs but also caused a significant degradation of the field quality of an assembled PMQ module by increasing the parasitic multipole field harmonics which effectively makes PMQs impractical for proton radiography applications or similar scenarios.

Performance of Crystal Scintillators in a Severe Radiation Environment Caused by Protons

Future high energy physics experiments at the energy and intensity frontiers will face challenges from a severe radiation environment caused by both ionization dose and charged and neutral hadrons. This paper reports an investigation on proton induced radiation damage in various crystal scintillators. Large size BGO, LFS and PWO crystals of 18 to 22 cm long were irradiated by 800 MeV protons up to 3 × 1015 p/cm2 at the WNR facility of LANSCE with longitudinal transmittance measured in situ. LYSO plates of 14 × 4 × 1.5 mm3 were irradiated by 24 GeV protons up to 8.2 × 1015 p/cm2 at the IRRAD facility of CERN. Degradations in both transmittance and light output are reported. The results show an excellent radiation hardness of LYSO/LFS crystals against charged hadrons.

Neutron irradiation and damage assessment of plastic scintillators of the Tile Calorimeter

Following the comparative study of proton induced radiation damage on various plastic scintillator samples from the ATLAS-CERN detector, a study on neutron irradiation and damage assessment on the same type of samples will be conducted. The samples will be irradiated with different dose rates of neutrons produced in favourable nuclear reactions using a radiofrequency linear particle accelerator as well as from the SAFARI nuclear reactor at NECSA. The MCNP 5 code will be utilized in simulating the neutron transport for determining the dose rate. Light transmission and light yield tests will be performed in order to assess the radiation damage on the scintillators. In addition, Raman spectroscopy and Electron Paramagnetic Resonance (EPR) analysis will be used to characterize the samples after irradiation. The project aims to extent these studies to include radiation assessment damage of any component that processes the scintillating light and deteriorates the quantum efficiency of the Tilecal detector, namely, photomultiplier tubes, wavelength shifting optical fibres and the readout electronics. They will also be exposed to neutron irradiation and the damage assessed in the same manner.

Proton-Induced Radiation Damage in Fast Crystal Scintillators

This paper reports proton-induced radiation damage in fast crystal scintillators. Large size LYSO and CeF3 crystals of 20 and 15 cm long were irradiated by 800 MeV protons at Los Alamos up to $3.3\times 10^{14}$ p/cm2 with degradation and recovery of their longitudinal transmittance measured in situ . LYSO plates of $14\times 14\times 1.5$ mm3 were irradiated by 67 MeV protons at UC Davis up to $9.5\times 10^{13}$ p/cm2, and by 24 GeV protons at CERN up to $6.9\times 10^{15}$ p/cm2. The results show an excellent radiation hardness of LYSO crystals against charged hadrons.

Correlated analysis of 2 MeV proton-induced radiation damage in CdZnTe crystals using photoluminescence and thermally stimulated current techniques

Radiation damage induced by 2MeV protons in CdZnTe crystals has been studied by means of photoluminescence (PL) and thermally stimulated current (TSC) techniques. A notable quenching of PL intensity is observed in the regions irradiated with a fluence of 6×1013p/cm2, suggesting the increase of non-radiative recombination centers. Moreover, the intensity of emission peak Dcomplex centered at 1.48eV dominates in the PL spectrum obtained from irradiated regions, ascribed to the increase of interstitial dislocation loops and A centers. The intensity of TSC spectra in irradiated regions decreases compared to the virgin regions, resulting from the charge collection inefficiency caused by proton-induced recombination centers. By comparing the intensity of identified traps obtained from numerical fitting using simultaneous multiple peak analysis (SIMPA) method, it suggests that proton irradiation under such dose can introduce high density of dislocation and A-centers in CdZnTe crystals, consistent with PL results.

Study on the bias-dependent effects of proton-induced damage in CdZnTe radiation detectors using ion beam induced charge microscopy

The influence of damage induced by 2MeV protons on CdZnTe radiation detectors is investigated using ion beam induced charge (IBIC) microscopy. Charge collection efficiency (CCE) in irradiated region is found to be degraded above a fluence of 3.3×1011p/cm2 and the energy spectrum is severely deteriorated with increasing fluence. Moreover, CCE maps obtained under the applied biases from 50V to 400V suggests that local radiation damage results in significant degradation of CCE uniformity, especially under low bias, i. e., 50V and 100V. The CCE nonuniformity induced by local radiation damage, however, can be greatly improved by increasing the detector applied bias. This bias-dependent effect of 2MeV proton-induced radiation damage in CdZnTe detectors is attributed to the interaction of electron cloud and radiation-induced displacement defects.

Proton induced radiation damage in fast crystal scintillators

This paper reports proton induced radiation damage in fast crystal scintillators. A 20cm long LYSO crystal, a 15cm long CeF3 crystal and four liquid scintillator based sealed quartz capillaries were irradiated by 800MeV protons at Los Alamos up to 3.3×1014p/cm2. Four 1.5mm thick LYSO plates were irradiated by 24GeV protons at CERN up to 6.9×1015p/cm2. The results show an excellent radiation hardness of LYSO crystals against charged hadrons.

The Effect of Proton Irradiation on the Critical Current of Commercially Produced YBCO Conductors

Samples of YBCO superconductor from two manufacturers were irradiated with protons at the BLIP facility at BNL. Two specimens of each type of conductor were irradiated to five fluences covering the range from 1016 to 4 times1017 protons/cm2. The beam parameters for the irradiations were 42 muA and 142 MeV. The critical current (zero field, 1 muV/cm) for all twenty samples was measured in liquid nitrogen before and after irradiation to quantify the effects of high-dose proton-induced radiation damage on the performance of the conductor, and thus evaluate its suitability for service in high-radiation environments. All of the specimens had a pre-irradiation current of about 100 A. This current decreased linearly with fluence, with a slope of about 20% per 1017 protons/cm2. The agreement between the two samples of each brand of conductor was exceptional.

Study of the Scintillation Properties and of the Proton-Induced Radiation Damage in the K2CeCl5 Single Crystal

Study of the Scintillation Properties and of the Proton-Induced Radiation Damage in the K2CeCl5 Single Crystal

Effects of radiation damage caused by proton irradiation on Multi-Pixel Photon Counters (MPPCs)

We have investigated the effects caused by proton-induced radiation damage on Multi-Pixel Photon Counter (MPPC), a pixelized photon detector developed by Hamamatsu Photonics. The leakage current of irradiated MPPC samples linearly increases with total irradiated doses due to radiation damage, which is not completely recovered even after a year from the irradiation. No significant change has been observed in the gains at least up to 8.0 Gy ( 9.1 × 10 7 n / mm 2 in 1 MeV neutron equivalent fluence, Φ eq ). The device has completely lost its photon-counting capability due to baseline fluctuations and noise pile-up after 21 Gy irradiation ( 2.4 × 10 8 n / mm 2 in Φ eq ), which might be problematic for some applications, such as ring-imaging Cherenkov detectors. We have found that the pulse-height resolution has been slightly deteriorated after 42 Gy irradiation ( 4.8 × 10 8 n / mm 2 in Φ eq ), where the measured sample has been illuminated with a few hundred photons. This effect should be considered in the case of energy-measurement applications.

In-flight proton-induced radiation damage to SCIAMACHY’s extended-wavelength InGaAs near-infrared detectors

The performance of the SCIAMACHY detectors has been monitored since launch. Only minor degradation of the silicon-based UV–Vis detectors and the lattice-matched InGaAs NIR detector is observed. The degradation of the NIR extended-wavelength InGaAs detector arrays, however, which are used for the first time in a space-based remote sensing application, is unexpectedly large. The degradation of individual detector pixels is abrupt and mostly leads to excessively high (spread in) dark current. Evidence is presented that non-ionizing radiation due to trapped-protons leads to displacement damage to the InGaAs detector material. The current degradation rate leads to a loss of approximately 50 out of 1024 pixels per channel per year.

An investigation of proton energy effects in SiGe HBT technology

We present the first investigation of low energy (1.75 MeV) proton irradiation in SiGe HBT's and discuss proton energy effects in SiGe HBT technology. The results show that after 1.75 MeV 1 /spl times/ 10/sup 14/ p/cm/sup 2/, a semi-insulating substrate is obtained and the peak quality factor of the monolithic inductors is improved by about 18% at 1.6 GHz. Although large current gain degradation for the SiGe HBT's was observed in the RF bias region after 1 /spl times/ 10/sup 14/ p/cm/sup 2/, the degradation in peak f/sub T/ is only about 11%. Proton energy studies from 1.75 MeV to 200 MeV in SiGe HBT's suggest that the conventional damage factor can be used to estimate energy-dependent proton-induced radiation damage in this technology.

Proton damage effects on p-channel CCDs

An experimental batch of p-buried channel CCDs has been fabricated and characterised for proton-induced radiation damage. Dark current effects were similar to conventional n-channel CCDs, but radiation-induced changes in charge transfer inefficiency were reduced by approximately a factor 3 for -30/spl deg/C operation and background signal /spl sim/2000 electrons/pixel; though this is a lower limit and further reduction may be possible in future CCD batches.

Measurement of proton-induced radiation damage effects in double-sided silicon microstrip detectors

The electrical characteristics of double-sided n-type silicon microstrip detectors were investigated after those detectors had received proton irradiation up to a fluence equivalent to 1.7×10 13 1 MeV neutrons/cm 2. This fluence is about twice as much as is expected for the CDF SVX II innermost layer during its first year. It is also approximately equal to the fluence expected at a radius of 12 cm from an interaction point during the first three years of operation of an LHC experiment. The detectors' p- and n-side leakage currents and their depletion voltages responded to the damage in a manner consistent with present models. Their total capacitance per active length increased by (2.0±0.7) × 10 −14 pF cm/[1MeV neutron] on the p-side. Their total capacitance increased by (1.5±0.1) × 10 −13 pF cm 2/[1 MeV neutron] on the n-side for a particular double-metal geometry. Their coupling capacitance was unchanged by this fluence. The study required development of a new method for determining full-depletion voltage; that method is also presented here.