Tritium - Science topic

Good luck Mahnaz Barmahuri and rock your experiment.

Certainly! If you're interested in the fundamental physics of tritium and methods of selective adsorption, here are some literature recommendations:

These resources cover various aspects of tritium, including its physics, production, and applications. Depending on your specific interests, you may find different sections of these publications more relevant to your study of selective adsorption methods.

Thank you for your constructive contributions, without prejudice or envy. This is what helps science to be science.

I think this is getting at the point:

Namely the main effect is that the neutrons are more massive than the protons so tritium is more massive (has more rest energy) than 3He.

Dear Mr. Tondeur,

First of all I notice that your message this time is much longer. There is a striking contrast between the 2 lines of your "universal rule" stated with confidence and the number of lines and arguments that you put forward this time to resolve the contradictions that appear.

My approach is simple, you state a rule and I challenge it with a counter example. You say that this case (that of Pb208) is more "subtle" than the previous one. This word "subtle" tends to make one think that there is a trap in the counter-example and therefore the argument would be fallacious. There is no malicious intent in the example given (Pb208). It is an example that has the merit of being very clear and leads to contradicting (paradoxically) your rule.

Let's come now to the notion of stability, you say that there are 2 types of stability:

1) an "absolute" stability

2) an "empirical" stability because in theory the nucleus (Pb208 in our case) should be unstable but the present experimental means do not allow to prove it because the half-life of Pb208 is too long.

In fact this classification seems to me to be based on an unspoken and implicit argument. Indeed, when the experiment goes in the direction of the theory, it is good, when it is the opposite, it is bad.

You will tell me that in the case of Pb208, it is still theoretically unstable, but that this will be difficult to prove. We can turn the argument around and tell you that as long as you have not proved its instability, it can be considered stable as and that it is the theory that needs to be revised.

Hi How to define Reaction ?can u share the simulation file? thanks

Dear Virendra Kumar Saxena Sir, Thanks for the reference. I will go through it.

regards.

Well,

https://iop.figshare.com/articles/_Comparison_of_the_tritium_concentration_a_EACs_equivalent_air_concentrations_of_CFC_12_b_and_SF_sub/1011859/1

Regards

Dear you can use chromatography

The Tritium Laboratory at the University of Miami sells dead water at $30/Liter. Their testing has determined it to be below their detection limit of 0.1 TU. Contact them for more information: https://tritium.rsmas.miami.edu

They are reusable !

but pay attention that your nylon is completely dray before screen exposition

For radiocarbon analysis via accelerator mass spectrometry (AMS), typical sample sizes are 0.5 - 1.0 mg C. If sample preparation incorporates minimal contamination, and the 14C:12C ratio isn't extremely low, some AMS facilities can produce good results with < ~0.1 mg C. On rare occasion, samples as low as tens of μg are acceptable if the sample is very pure and the processing methods have been vetted for contamination aka "blank effect." The smaller (or older) the sample, the more contamination will become a factor, and the measurement will have larger uncertainty. Care should be taken with all 14C sampling to avoid contamination (many potential sources can artificially add 14C or 12C disproportionately), but especially with small samples (< ~0.2 mg C) or very old C (with little remaining 14C). Good AMS facilities will ask for submission of calibration standards that underwent the same processing as the real samples. This helps determine any "blank effect" that the processing methods had on the true 14C:12C ratio of your sample. If the blank effect of the processing methods is proven to be consistent, it's possible to correct it out of the AMS results.

Hi Molly, was the problem solved? I am having the same problem with another old scintillation counter (Wallac 1409). Thanks!

Thank you a lot for the answer!

Yes, I thought that tritium was sufficiently stable but I wasn't sure.

I exposed the slides again and within a week I will see.

Hi Moumita,

Does the tritium assay involve a bit more handeling/pipetting? I always disliked doing assays with Colo-205 because they do not attach to the bottom of wells/plates.

Instead of replacing the whole medium to handle the cells, I would remove half carefully and adapt concentrations accordingly (something similar to suspension cultures).

Best,

Noel

The following link could help you.

Yes, Stefansson is right

In Romania  the Regulatory Body authorizes the systems of individual dosimetry and appoints the individual dosimetric services approved in compliance with the national regulations. The systems of dosimetry are used with the purpose of evaluating the individual penetrating dose equivalent, H(p)(10) and the individual superficial dose equivalent, H(p)(0,07).

The following types of dosimetric systems may be used with the purpose of the individual monitoring provided that they meet the requirements of these norms:

a) systems of dosimetry with film;

b) thermoluminiscent systems of dosimetry

c) electronic digital systems of dosimetry

Thank you

Dear Sir,

Our laboratory participated to inter-comparison exercises organized by OBT Group starting with 2013. The exercises measured Total OBT in different samples: potatoes, sediments, wheat, and now is ongoing, grass. Each exercise had dedicated meeting and during those meetings I saw communications about different techniques. If you have a Pyrolyser, you can catch combustion water in HNO3 solution of 0.1 M (RADDEC procedure). Be careful for level of OBT, because this procedure can be applied to high level of OBT. If you want to measure sample from uncontaminated environment (tritium concentration of combustion water below 10 Bq/L) you need to use a combustion bomb (we use Parr bomb), followed by neutralization and lyophilization of combustion water. LSC (Quantulus 1220) + Parr bomb + purification of combustion water can measure sample with OBT around 1 Bq/L in its combustion water. We use this procedure in our laboratory.

As a note to this problem,I learned recently the EDELWEISS-III collaboration found a way to 'measure' the H-3 production rate in germanium detector. somebody can download the paper from:https://arxiv.org/abs/1607.04560. 

I have experience with measurement on Quantulus 1220. So I’m using 8:12 ml ratio for sample:cocktail, as liquid scintillation cocktail UltimaGold uLLT (it has lower background than UltimaGold LLT). The background for UltimaGold LLT was around 0.8-1 CPM. Depleted water that I use it is distilled again by my self in the laboratory. When I set the parameters measurement for program 6, using QM, I add to SP11, and SP12 (implicit settings) SP21 and SP22, to see what it is happened outside the measurement chamber. You must check also the counts numbers in SP11, the interference phenomenon that can appear in sample are recorded there. Usually I don’t have more 0.08 CPM (for a bkg. around 0.6-0.7 CPM).

If you are using calibration curve for efficiency determination and a fixed windows, you will have a higher background due to auto adjusting of the windows for external irradiation. If you use internal standard method for counting determination, you must use EasyView in order to establish the optimized windows at the best FM (in fact varying the window you find a region in the tritium spectrum where you have in the same time the lower background of the measurement, and the higher measurement efficiency).

There are some other features that you can use in setting different level for PAC and PSA adapted to your type of cocktail. Try with PAC=10 and PSA =256, in order to have a bkg. reduction. These parameter you must establish adapted to your cocktail.

I worked with Biovision Glucose assay kit (Catalog #k606-100). We used the Fluorometric assay and could detect glucose in saliva. Please see the paper: Hartman M-L, Goodson JM, Barake R, Alsmadi, O, Al-Mutawa, Ariga, J Soparkar Behbehani J, Behbehani K, Welty, F. 2014 Salivary glucose concentration exhibits threshold kinetics in normal-weight, overweight, and obese children. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 2014:8 9-15. I did not compare this glucose test to the radioactive one therefore I don’t have an information on that.

I would suggest getting in touch with Geoff McDonnell, mentioned by Douglas Burns above, for a more balanced approach to the question. Bootstrap and similar techniques (like Monte-Carlo) may not be the best approach, depending on the processes occurring in your system, and the available data.

You do not need to convert unit of K, because its unit is 1/time. In model, this will be multiplied by time step. Thus, unit of concentration is not going to affect. You simply keep attention that unit of concentration in all components are consistent. Taking other value of k as zero is ok, if immobile phase is neglected.

I just try to check with zeolites Molecular Sieve beds and so on, but tritium always permeates even rafm steel...

Dr. Miler please contact Dr. Kazimier Rozanski at the University of Krakow. He is expert in this field

The answer is simple and not simple.  Obviously the main part is that they will be similar because the question involves chemistry.  The chemistry of the two are, of course, identical.  What is not identical is the size of the atom  (not much difference, but a small amount).  It also makes a slight difference if they actually react with the W into a deuteride or tritide or via some impurity in the W or if they are just adsorbed onto the surface.  The best solution is to make this a research problem if the small differences are important.

Hydride ion acts as a nucleophile.

At the same time, you want oxygen to receive this hydride.

Mm, Try using benzoyl peroxide, however, benzoic acid is not unexpected as a product.

Ozone also, as a reagent, might be able to form water from the reaction. 

I don't think that just rising the pressure will be sufficient - those 14 MeV neutrons have a very small cross section even with solids (lead for example does not shield neutrons effectively even with its high density).

Cadmium or Boron are good absorbers for neutrons but only for slow ones (so some 100 meV at most).

If you request custom tritium-labelled compounds for autoradiography, please contact RC TRITEC in Switzerland. We do not sell standards, but tritium-labelling of various compounds is our daily business. Please contact us at www.rctritec.com