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749 Uppsatser om Radiation dose reduction - Sida 1 av 50

MCNP-modell för beräkning av neutrondos och DPA på reaktortanken vid Ringhals 2

In this report an MCNP (Monte Carlo N-Particle) model is described for the reactor vessel at Ringhals 2. The model is validated against the specific activity in neutron dosimeters, extracted in 1977, 1984 and 1994. The validation showed that the calculations of the model are within the requirements of a maximum of 20 percent uncertainty for every neutron dosimeter except one, extracted after the first cycle. The uncertainty of this cycle was mostly due to the operation data rather than to the MCNP model.The model has been used to investigate various questions concerning radiation damage. The reliability of the traditional measure of radiation damage, fast neutron flux (En > 1MeV) has been evaluated.  This has been done by taking the ratio for this and another measure of radiation damage, DPA (Displacement Per Atom), for various positions and layers.

Utveckling av metod för retrospektiv bestämning av absorberad dos i korall medelst elektronspinnresonans

This diploma work was performed at the department for radiation physics at the Health University in Linköping. Its aim was to develop a method to retrospectively quantify the absorbed dose in coral. Coral is a material which suites well as a retrospective dosimeter because when exposed to radioactivity its induced free radicals are stable in time. The number of radicals is proportional to the accumulated dose so the dose can be calculated by quantifying the radicals. Therefore, coral can tell us something about the past environment and also be used in dating purposes.A young, modern coral from the Red Sea was studied and also a fossil one which I was given from the Natural History Museum in Stockholm.

Strålskydd :

This paper describes how radiation affects the body, the somatic and genetic effect that can occure in exposure of ionizing radiation and how to protect yourself against it. How radiation affects the cells and why you can get cancer if you get exposed of a large amount of radiation is mentioned. Research after a threshold is mentioned and what Sweden does today to improve the radiation protection by laws and regulations. Explaining the atom, what radiation is and how the ionizing radation interacts with the atom. How backscatter affect the picture and the workers and how to protect yourself from backscatter is mentioned. Radiation doses, dosimetry and rules for those who practise radiation is shortly described..

Metod för dosoptimering av digitalt detektorsystem i klinisk drift

The county of Dalarna is at present carrying through a process of digitalization where traditional x-ray film is being replaced with digital detectors. Earlier used methods for dose optimization turned out not being sufficient. This report presents a method to harmonize dose levels between x- ray sites equipped with Fujifilm imaging plate systems. An exposure index, S, related to the dose level of the examination is computed to every x-ray image. S turned out to be inversely proportional to the detector dose used at the examination.

Behovet av blyhandskar som skydd mot sekundärstrålning vid röntgenundersökning av djur

X-rays are a potential risk for animal health care personnel. The present study will examine the risks for scattered radiation to the personnel, if no lead gloves are used when holding an animal during the x-ray examination. Furthermore, how the impact of the exposure values and body parts examined, affect the scattered dose to the hands of the holder. Also, the distance between the animal and the hand that holds it was evaluated to see the impact on scattered radiation exposure. Tested by a survey, to animal health care students, the frequency of the usage of lead gloves in Swedish animal hospitals was studied. According to the results from the analysis, animal health care personnel don't need to use lead gloves every time they hold an animal or a cassette during x-ray examinations.

Påverkan på elektronik och sensorer i radiologisk miljö

The objective of this thesis is to make a training material for KSU, which shows how radiation affects the different electronic components in a radiological environment.All electronic systems in the presence of high ionizing radiation can experience difficulties and be destroyed.This influence may compromise the control system and thus the safety of a nuclear reactor plant.To achieve this objective requires a description of electronic components and sensors, to better understand its function.This thesis will also show the possible solutions available that the author found interesting.Organizations such as NASA, CERN and ESA have worked to develop electronic components immune to radiation. Those organizations have also developed a test protocol that guarantees to a certain extent the security of electronic components in a radiological environment.Since we know how the material reacts with the radiation, it could develop a material that can be resistant to radiation or like CMOS technology has proposed, to reduce the component to avoid the storage of charge in the oxide.Another solution can be the GRAPHENE. Its features will revolutionize the electronics and provide answer to the radiation problems, Graphene will replace Silicium and the electronic components will only have a few nanometers dimensions so the oxide area also reduces, and in this way avoid the known problem of storage of charge..

Mätutrustning för kosmisk strålning

The purpose with this examination is to build a measureequipment to AerotechTelub AB (AT), who will registrate fault in SRAM-memory in contact with cosmic radiation. The equipment will be created around developcard from Memec Design with FPGA from Xilinx. The logic in the FPGA will be implemented with the hardwaredescribed language VHDL. The SRAM-memory that will be tested is build in CMOS-teknologi. The memorycells will be loaded with a predecided bitpattern.

Undersökning av exponeringsindex för bildplattesystem inför optimeringsarbete

The county hospital of Dalarna has for the last couple of years carried through a process of digitalization. The result is that within the county it exists image plate systems from two different manufacturers. In an attempt to create a tool for dose optimization and dose surveillance the county of Dalarna would like to investigate if the exposure index from Agfa and Fuji is suitable as a dose indicator. An investigation of the exposure index, S, from Fuji has already been done. This thesis has been continuing the investigation by evaluating the stability of the exposure index, lgM, from Agfa.

Energiberäkningar för passivhus

AbstractClimate and environmental issues are of paramount importance. Researchers agreethat we must all contribute to a reduction of gases that contribute to climatechange. Energy consumption must decrease within all sectors and the promotionof renewable sources of energy must be introduced.Each sector should aspire to decrease its energy consumption. Energyconsumption is strongly linked to waste gases that contribute to climate change.Passive houses are a part of the construction industry's methods to attain energyconservation.Passive houses are derived from low energy houses and super insulated houses. Apassive house is intended to obtain heat from the inhabitants and through theiractivities.

Förändring av radiocesiumtillståndet i jordbruksgrödor i Gävleborgs, Västmanlands och Uppsala län efter Tjernobylolyckan samt en fallstudie med stallbalansberäkningar på en mjölkgård :

Several radioactive nuclides were deposited in Sweden after the Chernobyl accident in 1986. The greatest attention was given to 137Cs because of its relative long physical half life of about 30 years. 137Cs will be present in nature for more than 100 years before it has vanished completely. When radiocaesium decays to a stable end product ionizing radiation is emitted, which can cause cancer in humans that has been exposed to a high radiation dose. Radiocaesium behaves like potassium and is easily taken up into biological systems.

Hur påverkasogräsuppkomsten av jordbearbetning :

Today it is common to spray against most weeds by using very expensive weed-killers. The goal for every farmer is to have as low costs as possible for their use of machines and weed-killers. Therefore it is in everyones interest to find other methods to fight the weeds. Finding a way to reduce the rise and growth of weeds already at the preparation of the soil would lower the number of laps over the field and also decrease the amount of weed-killing dose. Tests show that by harrow in the dark it is possible to reduce the population of weeds with up to 60%, but the normal reduction would be about 20-30%. To verify the results above we made tests by using two different methods of preparing the soil. We tested ploughing and harrowing in daylight and during night. Later we checked the number of different weeds in areas prepared in daylight and during night. By studying the results from the different methods used we found a considerable reduction of some kinds of weeds in areas prepared during night..

Cancerbehandling för hund och katt

Cancer is one of the most feared diseases in veterinary medicine today, and the incidence is higher than ever due to the fact that our companion animals live longer then they did ten to twenty years ago. Cancer is also one of the most common causes of mortality in older companion animals. This literature review will be about two of the currently most common form of cancer treatment of companion animals in Swedish animal hospitals, chemotherapy and radiation therapy. There will also be a section of general nursing care for cancer patients. The section of chemotherapy will describe the indications for choosing chemotherapy, the way to administrate chemotherapeutic drugs, describe specific chemotherapeutic drugs, potential side effects of chemotherapy, and how to handle and store chemotherapeutic drugs safely. The section of radiation therapy will describe the current devices for delivering radiation therapy, describe the indications for choosing radiation therapy and describe potential side effects that radiation therapy may cause.

Våtmarken som renare av dagvatten

Eight healthy 3-day-old foals were given repeated injections of trimethoprim-sulfadiazine intravenously for 3 days, at a dosage of 15 mg/kg bodyweight (2,5 mg trimethoprim and 12,5 mg sulfadiazine). Blood samples were collected prior to each administration and for the following 24 hours after last administration. Serum concentrations of trimethoprim and sulfadiazine were measured and the pharmacokinetics for the substances were studied. The elimination half time (t½) and clearance (ClB) for trimethoprim and sulfadiazine for the foals did not diverge from adult horses. According to these data it is possible to assume that the same dose interval and dose can be used for foals as for adult horses.

Asymmetrier i travhästars rörelsemönster vid långsam och snabb trav

Eight healthy 3-day-old foals were given repeated injections of trimethoprim-sulfadiazine intravenously for 3 days, at a dosage of 15 mg/kg bodyweight (2,5 mg trimethoprim and 12,5 mg sulfadiazine). Blood samples were collected prior to each administration and for the following 24 hours after last administration. Serum concentrations of trimethoprim and sulfadiazine were measured and the pharmacokinetics for the substances were studied. The elimination half time (t½) and clearance (ClB) for trimethoprim and sulfadiazine for the foals did not diverge from adult horses. According to these data it is possible to assume that the same dose interval and dose can be used for foals as for adult horses.

Upprepad intravenös administrering av trimetoprim-sulfadiazin hos neonatala föl

Eight healthy 3-day-old foals were given repeated injections of trimethoprim-sulfadiazine intravenously for 3 days, at a dosage of 15 mg/kg bodyweight (2,5 mg trimethoprim and 12,5 mg sulfadiazine). Blood samples were collected prior to each administration and for the following 24 hours after last administration. Serum concentrations of trimethoprim and sulfadiazine were measured and the pharmacokinetics for the substances were studied. The elimination half time (t½) and clearance (ClB) for trimethoprim and sulfadiazine for the foals did not diverge from adult horses. According to these data it is possible to assume that the same dose interval and dose can be used for foals as for adult horses.

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