Questions related to Radiation Detection
My question is how to determine the efficiency of a "NaI(TI) Detector" its size is 3 × 3.
Radiation detection is done at different distances for various amount of energy. The results calculated from this method is similar with previous work.
But can't find the next step to calculate its efficacy.
Please help me
I am aware CR-39 (Columbia Resin 39) is mostly used in optical lenses, but I want to use them as ion track detectors. Hence, I need to adquire film-like or sheets of this plastic detector. I have no idea where to buy them! Any information is highly appretiated.
The website and manual are too general and do not explain well. I have the radiation data from sensors. Have to make a quality check. How can I use the BSRN toolbox to create station to archive file? The report and website are too naive' to explain.
Pl see the attached image. I want to calculate the detection limit using the following formula LD = 2.71 +3.29 (BACKGROUND COUNTS)^0.5
In 200 keV region there is a visible peak (assume >LC). In 300 keV region there is no visible peak (assume <LC).
What value for 'BACKGROUND COUNTS' should I use in both cases? In 200 keV energy, should I use gross counts as 'BACKGROUND COUNTS' i.e. a+b and what about in the case of 300 keV case? Pl reply.
n+ contact of p type Ge is ~700µm thick compared to p+ contact of n type Ge only ~0.3µm. The process of adding the contact is different. n+ contact Li is added by diffusion process but p+ contact B is added by ion implantation technique. In diffusion we can get only thick contact but in ion implantation we can achieve thin contact, Fine. With a thin (~0.3µm) Li ion implantation, low energy efficiency of p type HPGe detector can be on par with n type HPGe detector (as per the attached fig).
Why Li is also not added as contact by ion implantation method? Is it a mandatory requirement of having thick (~700µm) n+ contact or only due to technology used for doping, we are getting thick (~700µm) contact?
there is a p-type of HpGe detectors, this kind is characterized by the litium dead layer wich existe in the outer side of the detector cristal and it is increased with the passage of time ( dead layer= 0,7 mm if the detector is new ).
On the other hand, the n-ype of these detectors is characterized by a very thin dead layer ( in order of 10E-4 mm ) in the outer side and gross daed layer in the detector cavity.
Flowing our monte simulation of the n-type HpGE using MCNP gives a clair contrast with the expiremental results. where :
MCNP effeciency /Experemental effeciency <1 .
The insertion of the a dead layer ( dead layer depth= 0,08 mm) in the simulation improve the results especially in the <100 keV energy range.
My quation is, do what i did is correct ? and this value of the dead layer is reasonable after 20 years of functioning ? especially that in the leterature, the study of the dead layer of the n-type detector is rare and it is limited for the dead layer existing in the inere part (the cavity).
In CT scan variable intensity X Ray is passed through the object and an 3D image is recorded (Computed Tomography). Brain is covered by skull, made of high Z of Calcium. Inside skull brain is made up of low Z of C, H, O. How X ray is passing through skull and carries necessary information for image of brain and coming out from the opposite side, where again skull is present? Confused.
I did ROS assay using H2-DCFDA but could not find the function of detecting 2 wavelengths ( ex: 485, em: 520) at the same time as single reading in microplate reader so I got readings separately at the above mentioned wavelengths. I am not familiar well with this wavelength thing so I don't know how to analyze my result as I did ROS assay first time and don't even have idea that how it looks as combined reading. Can anyone please help me how to analyze the data? Any formula to calculate ROS from these wavelength values?
I have 2 separate readings (480nm and 520nm) for ROS assay.
Ruby (Al2O3 doped with Cr3+ ions), when exposed to ionizing radiation (for e.g. X-rays), emits luminescence. What is the mechanism that causes this 'Radio-luminescence? Does Cr3+ accept electrons or give up?
1. Can Compton Scattering like scattering happens for K shell electron like it happens for valence shell electron for X and Gamma Ray?
2. If yes, probability is more for K or Valence Shell electron? And more importantly why its high (either K or valence shell)?
Compton scattering do occur for low Z elements.
Cross-section for PE is prop to Z^5, for CS it is z^1.CS happens for z^1, then it should happen for for z^5 also.
Binding energy of K shell e has smaller value for low Z elements.
We want to buy an underwater detector for radiation protection purpose. Differentiating between natural (like radon and thoron) and artificial (like iodine and cesium) radio-nuclides is of more important in this project. We just want to buy one detector to do some test and get familiar with. After verification we plan to deploy a network in the sea. So currently I need no accessory or central server, I just need a stand alone device which I can communicate with a laptop.
I checked out AT6104DM(atomex), sara water(envinet) and Katerina. I contacted with the companies. Now for financial purpose I need to know price of them.
If any body has bought one of these devices or similar, kindly give me a clue about the price of them.
Also a training course by experts of company would be useful, Can you guess how does it cost?
How to estimate risk of stochastic effects mainly cancer for a given population exposed to low doses (5-10) mGy per year prevalent in High Background Radiation Areas without using the concept of collective dose as well as ICRP's accepted risk factor of ~5%/Sv?
Dear experts, I would like to ask that I am perform calculate shooting a ion beam to a thin target (several cm) and I use a sphere + cosine card (F1). but where should I locate the center of the sphere? in the middle of the target or on the surface behind of target.
Further more, Some one guide me how to plot graphic and geometry?
Thank you very much.
Can anyone provide references to radiation measurement data collected on patients who have undergone various NM procedures?
In the commercial available charge sensitive preamplifier for semiconductor radiation detector.Generally the HV(High Voltage) bias given to the semiconductor detector is through the charge sensitive preamplifier. Why it is done like this?
Why HV bias is not given separately to the semiconductor detector?
I will be very much thankful for the reply.
I have tried several plastic tubes for closed loop radon measurements but I found that the radon can penetrate trough so many of them. It causes significant radon loss if the sampling is continuous.
Do you have any experience in case of different plastic tubes? Which one is the best?
In the radiation detector the pulse shaping circuit consists of CR-RC circuit and amplifier.The function of pulse shaping amplifier is to improve Signal to Noise ratio.It also act as a filter to remove the noise since it consists of CR-RC circuit which represent differentiator and Integreator . The preamplifier input given to the pulse shaping circuit generates the Gaussian Pulse as the output response. I have seen that the tailing edge of the Gaussian pulse consists undershoot. There is a need for baseline restore through Pole-Zero circuit.Why this undershoot occur in the output of pulse shaping amplifier?How does Pole-Zero adjustment removes this undershoot?
I will be very much thankful for the reply.
Generally there are three types of noise is present in the semiconductor radiation detector.These are Thermal Noise,Shot noise and Flicker Noise.The thermal noise is removed by operating the detector under low temperature.The Flicker noise can be removed by using High pass circuit.But How to eliminate the Shot noise in the Semiconductor radiation detector?The shot noise in the semiconductor radiation detector is due to the discrete flow of carrier in the device. I will be very much thankful for the help if any one suggest some method to eliminate the shot noise?
I use a NaI detector which is powered by a digibase (integrated bias supply, preamplifier and MCA) and I find that its linearity is not quite good .( 5-6%).
I'm measuring radioactivity in granites and If I use 609 and 2614 Kev for linear calibration E=a*Ch +b , I get a difference 80KeV in the 1461KeV (Im interested in linear and not second order calibration)
If anyone uses such a system I would appreciate if he could send me information about the linearity of his system
In the reliability analysis of repairable and redundant safety systems someone needs to consider the effect of maintenance program. We are developing a Markov model for the ECCS system of a typical PWR reactor and for transition rates calculation we need the typical values of test interval and test duration for the ECCS system of a PWR nuclear reactor.
- To determine the neck thickness I need to calculate the forward range of electrons which might be produced by the Ion beam interactions.Since the range of Ion beam itself is in Microns,Is it safe to assume that if I keep my neck thickness around 2-3mm the electrons emitted in the forward direction won't leave the cup surface?.
I was measuring radon with AlphaE (product of Saphymo)
On the screen, the "NOISE" response appeared.
I tried to start another measurement but the "NOISE" was still on it during several days...
I could not find sufficient info in the instrument manual...
Many thanks for your help
I performed the radiation dose calculations and radiological consequences of a hypothetical accident by HotSpot, How to calculate values of error bars shown in figures? How to calculate combined relative error?
I am currently trying to understand the theory of cosmic radiations. I also want to know the magnitude of cosmic radiations in Germany for the last 6 years. Can any one suggest me a good source? Further, can you say me what is the unit for measurement of cosmic radiations?
The characteristics graph of Geiger Muller Counter always keeps going up and does not drop down . It may remain constant over an interval but does not drop down on the graph scale. Why it does not come down after going up?
Dear colleagues. One contaminated herself with final [18F]FDG product. Hand-Foot monitor with plastic scintillator coated with ZnS shows 7kcps alpha contamination. I have doubts that there was alpha particles. Detector is covered with thick plastic wrap foil and 18F should be pure. It was obtained in 18O(p,n)18F reaction after purification on several cartriges. Is that alpha detection a false positive result? Is it possible that monitors pulse discriminator or high voltage on PMT is badly configured ?
Dear engineer Why win-q disconnected to quantulus 1220?.what can i do to solve this problem.I turn on and off system and counter but win-q display disconnected massage in application.I reinstalled app. But win-q is disconnect .at first its error was conveyor clearing but after turn off & on it shows disconnected. we check the plates and remove trays and check them.they dont have any problem. please answer my question. I need to answer .best regard((when counter time was over the elevator took vial at tray and after that we hearing the pneumatic pomp tone(Eu-152,STD capsule) more and more.after that we turn on & off several times.but after that application showed disconnected))
Durridge Inc. RAd7 monitor measures radon concentration from alpha energy spectrum.
Removing inlet filter should in principle allow to measure at least time variations in equlibrium factor, since a fraction of radon daughters is expected to be trapped in the drying column.
Anyone who tried or found literature about this? Thank you in advance for any suggestion
I am doing experiments where I am feeding Arabidopsis plants with radioactive phosphate (33P) to measure rate of Pi uptake. We will measure the uptake by scintillation counter which will give the data in counts per minute. How to convert counts per minute data into nanomoles phosphate per mg of plant tissues? Please let me know. Thanks.
I am conducting a radiation dose exposure and risk assessment on native peoples in the USA and several other countries. I am interested to learn if anyone has been reporting low dose results and in particular in relation to indigenous peoples.
How will it make a difference if gamma spectroscopy is carried out using powder rather than crystal. I think resolution will be poor but why I am not able to make it out.
Particularly I am interested in threshold values for 226Ra, 232Th and 40K activities in nitrogen, phosphorus and potassium fertilizers.
Any input is highly appreciated.
Nuclear track detector CR-39 is made of is a sample of a solid material, so if we irradiate this detector by He-Ne laser so what is the effect of that on track detector properties?
I saw some pre-amplifier specifications and all of them say noise in terms of energy ( for example 2.8 keV for Si). If I convert this energy to charge (4eV per e-h pair in silicon) and convert the charge to average current taking an integration time of 10 us, it turns out to be around 11 pA.
Does that mean the minimum signal current that the preamplifier detects and then integrates is 11 pA?
This number is very low but is not reported in literature. It depends on the system, obviously, but an order of magnitude in at least one case could be useful.
PPC cement, coarse aggregate ( mixture of 3/4 th inch & 1/2 inch downgraded stone chips), fine aggregate (coarse sand), and admixture (MasterPolyheed) is used for this construction.
Fresh density is kept above 2.4 gm per cc. The hardened density requirement is above 2.35 gm per cc.
Ice is being used to decrease the mixing water temperature. (To avoid hairline crack in the future)
Key concern is to avoid radiation leakage.
The rooms are being constructed in the basement with wall thickness of 5 to 8 feet and slab thickness of 4 to 8.5 feet. Rooms will be used for Oncology treatment and/or Tomotherapy.
We are looking at electrons, protons and ions generated from our LPP x-ray source which passes through an electrostatic analyzer before reaching the detector. Can anyone tell us, which is best to use, the electron multiplier tube or the micro channel plates?
I measured some water samples from Kabul-Afghanistan by means of ICP-MS to look for the concentrations of radionuclide, I measured considerable amount of Uranium-238 (Still under the WHO permissible limit), but as a very active element of Uranium series progeny, I couldn't see any counts for Ra-226, I couldn't find reasonably good interpretation of the absence of Ra-226, any body have any good explanation for this absence ? I am a physicist not a chemist, so please enlighten me about the issue.
Thank you very much in advance
Geiger counters work in environments with different kinds of radiation types. How dose it measures radiation dose in sivert unit?
Is there any reference data available for reliability and availability of GM based radiation survey meters which are used for routine survey purpose in industrial or medical institutions.
Knoll's book says "An estimate can be made of the amount of inherent fluctuation by assuming that the formation of each charge carrier is a Poisson processes".
What is the basis of Poisson process?
Does this assumption holds true in every detector, if not why does it fail?
Some researchers insist on the presence of a NIST standards in each Neutron Activation Analysis, saying: “ Certified Reference Material GBW 0xxxx (for example) cannot be used as standard. It can be only used as Reference Material for the estimation of precision and accuracy of results”.
Why? Is it really inevitable to use a NIST standards, if so what is the use in the IAEA standards - for example-?
Using the method of Laplace Inverse Transform, proposed by B.R. Archer et al. (1982-1988), we can get an x-ray spectrum from the Transmission Data where we need to use the values of mass attenuation coefficients. Not only this method but other methods also involve the use of the mass attenuation coefficients for the beam attenuating materials and these values are very sensitive to get an accurate x-ray spectrum back. If we use the mass attenuation values from NIST (that includes scattering, photoelectric absorption and pair production), can we also use the same values in the backward calculation? By backward calculation I mean the calculation of the Transmission Data using the X-ray spectrum in the following way:
Or any other factors related to the geometry of the x-ray machine (that contribute the secondary x-rays passing through the attenuators and/or detectors) also need to be considered?
92.3 & 92.8 keV gamma peak shall appear as the single peak as the FWHM is 2-3 keV in HPGe detector.
If X ray of 93.350 keV contributes...what will be the % of contribution (% w.r.t gamma)?
Assuming no x ray cut off shield is used.
If the results of activity size distribution (AMD and GSD) depend on the ventilation rate, sampling location, and room size. why we make comparison in some papers? what is the value of measurment reating in some cases?
Leakage as I know is the ratio of activity lost through glue or rubber and so on>>
= radon activity pass through material with out Bg/total Activity with out Bg?
is this true?
For long term fading study (2 years post irradiation) of a TL material we have seen about 50% decrease in TL signal for the samples irradiated with the doses up to 2 Gy but a 30% increase in TL signal for doses above 3 Gy – 25 Gy when compared with the results of 24 hours post irradiation. which mechanism can explain it?
Can anyone explain me how does the detector parameters (like capacitance, leakage current etc.) affect the choice of feedback capacitance in the design of a charge sensitive pre-amplifier for radiation detection?
Suppose the energy required to produce a single electron-hole pair in a semiconductor is given by 'ε' Then the number of electron-hole pairs produced by a particle depositing energy E in the material is E/ε. Let us say this quantity 'N'. Now what is the total amount of charge inside the material: is it (a) N*e or is it (b) 2*N*e ? (e= charge on an electron).
I have an ultraradiacTM-plus personal radiation meter (a type of GM tube), give a pre-settable alarms for both instantaneous rate and cumulative dose. I want to know if there is any research using this meter, or its practical field uses, if anybody uses it .
Like other solid state scintillation detector viz NaI(Tl), CsI(Tl) etc detector why ZnS(Ag) detector can't be used for Gamma counting also? Why ZnS(Ag) is used specifically or can be used specifically for alpha counting only? Can we used NaI(Tl) detector with suitable modifications in the design as alpha counting?
Solid salt such as rubidium sulfate is known to emit atomic emission of light only when subjected to high temperatures. Recent study has unfolded that gamma irradiation of the salt can cause atomic emission of light notably at room temperature. What is the technique involved?