Radiation Damage Monitoring Research Articles

CMS HF Dedektöründe Kullanılan Fiberlerin Radyasyondan Gördüğü Zararı Görüntüleme Sistemi

İleri Hadron (HF) dedektörü, Compact Muon Solenoid (CMS) deneyinin her iki yanında bulunup, CMS'nin çok ileri bölgedeki pseudorapidite (3.0 < | η | < 5.0) aralığını kapsar. Her bir HF modülü, demir soğurucuların uzunluğu boyunca ışın demeti eksenine paralel uzanan kuvars liflerinden yapılmıştır. HF, ışın eksenine yakın olduğu için yüksek düzeyde radyasyona maruz kalır. Ve yüksek radyasyon etkisi nedeniyle, kuvars fiberler zamanla bozulmaya başlar. Bu radyasyon etkisini belirlemek için HF detektörüne bazı özel fiberler yerleştirilmiştir. Radyasyonun neden olduğu hasarı izlemek için toplam 56 fiber kanalı kullanılmıştır. Bu çalışma, HF'nin radyasyon hasarının izlenmesi için 2010 yılı çalışma döneminde alınan yerel lazer verileri kullanılarak yapılmıştır. Belirli bir pseudorapidite ve azimutal açıda RadDam kanallarında önemli bir radyasyon hasarı gözlenmemiştir.

An upgrade of the materials irradiation facility with in-situ electrical resistivity measurement at the Demokritos TANDEM accelerator

As an important part of fusion materials research, evaluation of radiation damage in fusion materials has been emphasized more than a half century. In order to improve our understanding of radiation damage in fusion materials, an upgrade has been performed of the materials irradiation facility IR2, which is located at the NCSR “Demokritos” 5.5 MV TANDEM accelerator. The upgraded facility allows irradiation at higher ion beam currents while ensuring that the target temperature remains below 10 K. It provides in-situ electrical resistivity measurements on several samples for real-time monitoring of radiation damage as well as in-situ post-irradiation annealing up to 300 K. The upgraded IR2 facility has been successfully employed in radiation damage and recovery studies of metallic materials with applications in fusion research.

PET Imaging of PARP Expression Using 18F-Olaparib.

Poly(ADP-ribose) polymerase (PARP) inhibitors are increasingly being studied as cancer drugs, as single agents, or as a part of combination therapies. Imaging of PARP using a radiolabeled inhibitor has been proposed for patient selection, outcome prediction, dose optimization, genotoxic therapy evaluation, and target engagement imaging of novel PARP-targeting agents. Methods: Here, via the copper-mediated 18F-radiofluorination of aryl boronic esters, we accessed, for the first time (to our knowledge), the 18F-radiolabeled isotopolog of the Food and Drug Administration–approved PARP inhibitor olaparib. The use of the 18F-labeled equivalent of olaparib allows direct prediction of the distribution of olaparib, given its exact structural likeness to the native, nonradiolabeled drug. Results: 18F-olaparib was taken up selectively in vitro in PARP-1–expressing cells. Irradiation increased PARP-1 expression and 18F-olaparib uptake in a radiation-dose–dependent fashion. PET imaging in mice showed specific uptake of 18F-olaparib in tumors expressing PARP-1 (3.2% ± 0.36% of the injected dose per gram of tissue in PSN-1 xenografts), correlating linearly with PARP-1 expression. Two hours after irradiation of the tumor (10 Gy), uptake of 18F-olaparib increased by 70% (P = 0.025). Conclusion: Taken together, we show that 18F-olaparib has great potential for noninvasive tumor imaging and monitoring of radiation damage.

The LHCb Silicon Tracker

The aim of the LHCb experiment is to study rare heavy quark decays and CP violation with the high rate of beauty and charmed hadrons produced in pp collisions at the LHC. The detector is designed as a single-arm forward spectrometer with excellent tracking and particle identification performance. The Silicon Tracker is a key part of the tracking system to measure the particle trajectories to high precision. This paper reports the performance as well as the results of the radiation damage monitoring based on leakage currents and on charge collection efficiency scans during the data taking in the LHC Run I.

Radiation damage monitoring in the ATLAS pixel detector

We describe the implementation of radiation damage monitoring using measurement of leakage current in the ATLAS silicon pixel sensors. The dependence of the leakage current upon the integrated luminosity is presented. The measurement of the radiation damage corresponding to an integrated luminosity 5.6fb−1 is presented along with a comparison to a model.

ATLAS pixel radiation monitoring with the high voltage delivery system

Abstract We describe the principles of radiation damage monitoring using current measurement of the pixel sensors to be provided by the circuits of ATLAS Pixel Detector high voltage delivery (HVPP4) system. The dependence of the leakage current upon the integrated luminosity for several temperature scenarios is presented. Based on the analysis we have determined the sensitivity specifications for a Current Measurement System under development at the University of New Mexico, USA and CERN. The status of the development is presented as well, and some characteristics of the prototype system are shown.

Radiation damage microstructures in silicon and application in position sensitive charged particle detection

Area selective irradiation using MeV ions having different ranges has been performed in a nuclear microprobe to produce radiation damage microstructures in silicon photodiodes. IBIC (Ion Beam Induced Charge) technique has been used for on line monitoring of radiation damage produced by different fluences of He, Li and O ions of MeV energies. Three-dimensional patterning of radiation damage structures may be used for different applications. By creating a region of constant damage gradient in Si photodiode, position sensitive radiation detection has been demonstrated.

A system for radiation damage monitoring

An automatic radiation damage monitoring system has been developed and tested. The system is based on two passive sensors for the measurement of integral ionizing and non-ionizing energy losses in silicon devices. Ionizing dose is measured in terms of dose in SiO/sub 2/ and displacement damage in terms of 1 MeV(Si) equivalent neutron fluence. The system uses MOSFETs and PIN dosimetric diodes.

Quality control and monitoring of radiation damage in charge coupled devices at the Stanford Linear Collider

The radiation testing of CCDs (charge coupled devices) for the vertex detector now installed at the SLAC (Stanford Linear Accelerator Center) Linear Collider is described. In addition to data from the batch qualification, results are also presented on the effect of biasing the CCDs during irradiation. A comparison between Co/sup 60/ and Sr/sup 90/ irradiation is made, and initial results for radiation effects in the vertex detector during operations are presented. It has been shown that commercial CCDs can be used as silicon tracking arrays in the radiation environment close to the interaction point at the SLC (SLAC Linear Collider). Measurements of reset FET turn-on potentials on the vertex detector in situ indicate an accumulated dose consistent with that extrapolated from remote dosimetry. Given the well-defined beam conditions that SLC now routinely maintains, these measurements indicate that the detector operation will not be significantly degraded during its lifetime.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In Situ Monitoring of Radiation Damage to Thermal Silicon Dioxide Films Exposed to Downstream Oxygen Plasmas

Field effect transistors with exposed gate insulators were used as in situ monitors of the effects of downstream oxygen plasma exposure on the system. The source to drain current of the field effect transistor was monitored before, during, and after plasma processing. At a fixed source to drain potential difference, devices displayed a drain‐current decrease during plasma exposure; this indicates an increase in the fixed negative charge in the oxide and/or a decreased transconductance due to an increase in the density of interface traps. A portion of the drain‐current decrease was recovered after exposure to room air or in situ exposure to water vapor suggesting that the drain‐current decrease was caused by electron‐trapping at water‐related traps in the oxide. The remainder of the drain‐current decrease was recovered after annealing at 400°C in forming gas and was caused most likely by electron‐trapping at neutral electron traps. Substrate currents were generated during plasma exposure indicating that electron injection from the substrate was the probable source of electrons trapped in the oxide. Vacuum UV photons with energies greater than the bandgap of (∼9 eV) and electron injection into the due to surface‐charging most likely were responsible for formation of neutral electron traps.

Online monitoring of radiation damage in optical fibers

We describe a setup which is able to monitor the behavior of optical materials during irradiation. We present measurements of the change in transmission for optical fibers and the recovering after irradiation. A measurement precision of about 2% is obtained.

On-line monitoring of radiation damage in optical fibers

We report on the construction and the performance of a setup which is monitoring the transmission of optical materials during irradiation with a measurement precision of about 2%.

Fast Neutron Damaging in Nuclear Reactors. I. Radiation Damage Monitoring with the Electrical Conductivity of Graphite

Fast Neutron Damaging in Nuclear Reactors. I. Radiation Damage Monitoring with the Electrical Conductivity of Graphite