18 research outputs found
Signal and noise of Diamond Pixel Detectors at High Radiation Fluences
CVD diamond is an attractive material option for LHC vertex detectors because
of its strong radiation-hardness causal to its large band gap and strong
lattice. In particular, pixel detectors operating close to the interaction
point profit from tiny leakage currents and small pixel capacitances of diamond
resulting in low noise figures when compared to silicon. On the other hand, the
charge signal from traversing high energy particles is smaller in diamond than
in silicon by a factor of about 2.2. Therefore, a quantitative determination of
the signal-to-noise ratio (S/N) of diamond in comparison with silicon at
fluences in excess of 10 n cm, which are expected for the
LHC upgrade, is important. Based on measurements of irradiated diamond sensors
and the FE-I4 pixel readout chip design, we determine the signal and the noise
of diamond pixel detectors irradiated with high particle fluences. To
characterize the effect of the radiation damage on the materials and the signal
decrease, the change of the mean free path of the charge
carriers is determined as a function of irradiation fluence. We make use of the
FE-I4 pixel chip developed for ATLAS upgrades to realistically estimate the
expected noise figures: the expected leakage current at a given fluence is
taken from calibrated calculations and the pixel capacitance is measured using
a purposely developed chip (PixCap). We compare the resulting S/N figures with
those for planar silicon pixel detectors using published charge loss
measurements and the same extrapolation methods as for diamond. It is shown
that the expected S/N of a diamond pixel detector with pixel pitches typical
for LHC, exceeds that of planar silicon pixels at fluences beyond 10
particles cm, the exact value only depending on the maximum operation
voltage assumed for irradiated silicon pixel detectors
A study of the radiation tolerance of cvd diamond to 70 mev protons, fast neutrons and 200 mev pions
We measured the radiation tolerance of commercially available diamonds grown by the Chemical Vapor Deposition process by measuring the charge created by a 120 GeV hadron beam in a 50 ÎŒm pitch strip detector fabricated on each diamond sample before and after irradiation. We irradiated one group of samples with 70 MeV protons, a second group of samples with fast reactor neutrons (defined as energy greater than 0.1 MeV), and a third group of samples with 200 MeV pions, in steps, to (8.8±0.9) Ă 10 protons/cm, (1.43±0.14) Ă 10 neutrons/cm, and (6.5±1.4) Ă 1014 pions/cm, respectively. By observing the charge induced due to the separation of electronâhole pairs created by the passage of the hadron beam through each sample, on an event-by-event basis, as a function of irradiation fluence, we conclude all datasets can be described by a first-order damage equation and independently calculate the damage constant for 70 MeV protons, fast reactor neutrons, and 200 MeV pions. We find the damage constant for diamond irradiated with 70 MeV protons to be 1.62±0.07(stat)±0.16(syst)Ă 10â18 cm/(pÎŒm), the damage constant for diamond irradiated with fast reactor neutrons to be 2.65±0.13(stat)±0.18(syst)Ă 10â18 cm/(nÎŒm), and the damage constant for diamond irradiated with 200 MeV pions to be 2.0±0.2(stat)±0.5(syst)Ă 10â18 cm/(ÏÎŒm). The damage constants from this measurement were analyzed together with our previously published 24 GeV proton irradiation and 800 MeV proton irradiation damage constant data to derive the first comprehensive set of relative damage constants for Chemical Vapor Deposition diamond. We find 70 MeV protons are 2.60 ± 0.29 times more damaging than 24 GeV protons, fast reactor neutrons are 4.3 ± 0.4 times more damaging than 24 GeV protons, and 200 MeV pions are 3.2 ± 0.8 more damaging than 24 GeV protons. We also observe the measured data can be described by a universal damage curve for all proton, neutron, and pion irradiations we performed of Chemical Vapor Deposition diamond. Finally, we confirm the spatial uniformity of the collected charge increases with fluence for polycrystalline Chemical Vapor Deposition diamond, and this effect can also be described by a universal curve
A Study of the Radiation Tolerance of CVD Diamond to 70 MeV Protons, Fast Neutrons and 200 MeV Pions
Radiation tolerance of diamond detectors
Diamond is used as detector material in high energy physics experiments due to its inherent radiation tolerance. The RD42 collaboration has measured the radiation tolerance of chemical vapour deposition (CVD) diamond against proton, pion, and neutron irradiation. Results of this study are summarized in this article. The radiation tolerance of diamond detectors can be further enhanced by using a 3D electrode geometry. We present preliminary results of a poly-crystalline CVD (pCVD) diamond detector with a 3D electrode geometry after irradiation and compare to planar devices of roughly the same thickness.ISSN:1742-6588ISSN:1742-659
Diamond Particle Detectors for High Energy Physics
Diamond devices have now become ubiquitous in the LHC experiments, finding applications in beam background monitoring and luminosity measuring systems. This sensor material is now maturing to the point that the large pads in existing diamond detectors are being replaced by highly granular tracking devices, in both pixel and strip configurations, for detector systems that will be used in Run II at the LHC and beyond. The RD42 collaboration has continued to seek out additional diamond manufacturers and quantify the limits of the radiation tolerance of this material. The ATLAS experiment has recently installed, and is now commissioning a fully-fledged pixel tracking detector system based on diamond sensors. Finally, RD42 has recently demonstrated the viability of 3D biased diamond sensors that can be operated at very low voltages with full charge collection. These proceedings describe all of these advances
Recent progress in CVD diamond detector R&D
We present an overview of the latest developments from RD42 in diamond detector R&D. They include the radiation hardness coefficients for 800MeV and 24 GeV protons, the hit detection efficiency for two 3D detector prototypes with two different readout chips and a novel method for investigating charge transport in single crystal diamonds.ISSN:1824-803
A study of the radiation tolerance of cvd diamond to 70 mev protons, fast neutrons and 200 mev pions
We measured the radiation tolerance of commercially available diamonds grown by the Chemical Vapor Deposition process by measuring the charge created by a 120 GeV hadron beam in a 50 ”m pitch strip detector fabricated on each diamond sample before and after irradiation. We irradiated one group of samples with 70 MeV protons, a second group of samples with fast reactor neutrons (defined as energy greater than 0.1 MeV), and a third group of samples with 200 MeV pions, in steps, to (8.8 ± 0.9) Ă 1015 protons/cm2, (1.43 ± 0.14) Ă 1016 neutrons/cm2, and (6.5 ± 1.4) Ă 1014 pions/cm2, respectively. By observing the charge induced due to the separation of electronâhole pairs created by the passage of the hadron beam through each sample, on an event-by-event basis, as a function of irradiation fluence, we conclude all datasets can be described by a first-order damage equation and independently calculate the damage constant for 70 MeV protons, fast reactor neutrons, and 200 MeV pions. We find the damage constant for diamond irradiated with 70 MeV protons to be 1.62 ± 0.07 (stat) ± 0.16 (syst) Ă 10â18 cm2 /(p ”m), the damage constant for diamond irradiated with fast reactor neutrons to be 2.65 ± 0.13 (stat) ± 0.18 (syst) Ă 10â18 cm2 /(n ”m), and the damage constant for diamond irradiated with 200 MeV pions to be 2.0 ± 0.2 (stat) ± 0.5 (syst) Ă 10â18 cm2 /(Ï Â”m). The damage constants from this measurement were analyzed together with our previously published 24 GeV proton irradiation and 800 MeV proton irradiation damage constant data to derive the first comprehensive set of relative damage constants for Chemical Vapor Deposition diamond. We find 70 MeV protons are 2.60 ± 0.29 times more damaging than 24 GeV protons, fast reactor neutrons are 4.3 ± 0.4 times more damaging than 24 GeV protons, and 200 MeV pions are 3.2 ± 0.8 more damaging than 24 GeV protons. We also observe the measured data can be described by a universal damage curve for all proton, neutron, and pion irradiations we performed of Chemical Vapor Deposition diamond. Finally, we confirm the spatial uniformity of the collected charge increases with fluence for polycrystalline Chemical Vapor Deposition diamond, and this effect can also be described by a universal curve. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.ISSN:1424-822