Pokhran II not fully successful: Scientist - Part-2

geeth · Post by **geeth** » 09 Sep 2009 15:46

>>>In spherical you can't do goal Mal

Ahem, even with my poor Hindi, I feel it is gol (sphere)..and Maal

>>>In cylindical you can store goal mal neatly

Again, isn't better to store cylinder into the gol (sphere) neatly..?

Cheer up Snow Garu! we can fit anything to anything else...if there is a will.

shiv · Post by **shiv** » 09 Sep 2009 16:05

Re how many holes does one need to drill to test radioactivity after a test.Cavity diameter is nowhere in the picture

http://www.globalsecurity.org/wmd/intro/ugt.htm

It appears likely that the drilling technology needed to emplace nuclear devices and instruments at the bottom of a deep borehole is the most difficult for a proliferator to acquire and use. Such boreholes are frequently a kilometer or more deep and 2 meters or more in diameter. The specialized drilling machinery required for such construction is not commonly available and exceeds what is found in the oil industry.

The most accurate measurement of yield is through the radio-chemistry studies of device debris -— the radioactive isotopes produced in the detonation. No electronics are used to gather the data for such analyses; it is only necessary to drill back into the device chamber and to extract samples for lab examination. A faster but less accurate yield determination can be done using seismographs to measure ground motion, but such a test would not collect a large quantity of data usually considered desirable by US weapon designers and testers. Radioactive debris from an atmospheric test or from an underground shot which vents can be analyzed by other nations. Much information about the design and performance of the test device can be inferred from the debris.

Only with a large collection of data derived from yield tests of different
types of devices can a weapons designer be confident that he understands the behavior of different possible designs within what is termed the nuclear weapons “design space,” and only then can he be confident that the computer programs used to predict device performance deliver reliable results. This may be the strongest motivation for a proliferator to test at full yield. However, even a series of full-yield tests may not provide all of the information needed for weapons design.

shiv · Post by **shiv** » 09 Sep 2009 16:21

As I stated in the last avatar of this thread - all this cavity radius - shavity radius business in measuring post shot radioactivity is rubbish. The real method is to sample the debris in the cavity and that has not been made public. The paper by Sikka about post shot radioactivity has clearly been critcised as long ago as 2001 - so even that is not new.

Here is the link and the statements about the best method to check yields

http://nuclearweaponarchive.org/India/I ... ields.html

One radiochemical analysis of the thermonuclear device test has been published in the BARC newsletter, [Manohar et al 1999]. This analysis attempts to calculate the total quantity of fissions that occurred and thus the total yield of the device (a fission-fusion-fission system in which fission would dominate the total yield). The method chosen was to measure the vertical distribution of fission products and fusion neutron activated isotopes in two bore holes (one at the center, and one offset by 32 m). Then by assuming a uniform distribution out to an estimated radius of the final cavity (claimed to be 40 m +/- 4m) the total quantity of isotopes was estimated. The yield estimate obtained was 50 kt with a claimed uncertainty of +/- 10 kt.

Radiochemical analysis is commonly said to be the most accurate means of yield determination. But this statement refers to an entirely different type of radiochemical analysis from what BARC performed in this study. The most accurate method is to determine the percentage of material fissioned by comparing the ratio of fission products to fissile material in a sample, thus giving the efficiency directly and with knowledge of the weapon design (how much fissile material is present) the yield can be easily calculated. Unfortunately publishing such data also discloses weapon design information normally kept secret. Attempting to directly calculate the total amount of fission is fraught with problems in accurately determining the three dimensional distribution of the material throughout the collapsed blast cavity.

In other words BARC has not released the crucial data. Criticising the data they have released is like Tanajis apt analogy.

We have no new data and we have all the same arguments being rehashed over and over again.

geeth · Post by **geeth** » 09 Sep 2009 16:40

I now understand where from the two-hole theory is derived!

rakall · Post by **rakall** » 09 Sep 2009 16:40

To quote the quote-master NSSidhu....

"Statistics are like mini-skirts... they reveal a lot.. but what they cover is vital".

something similar is happening in this case.

Dileep · Post by **Dileep** » 09 Sep 2009 16:46

It is inconceivable that a paper written for peer review would contain obvious glaring flaws that could be pointed out by people from outside the domain.

Now we figure why the NPA Whatshisname called it "Shitty Science". He expected the real radiochemical analysis report, where what he got was this radio spectroscopic analysis. Rather than trying to figure the merits/demerits of this method, he just branded it as "Shitty Science" and tossed it away.

Since this is "analogy season", let me try my hand on that. It is like an american food critic slamming the good old thaTTu dosas as "Pancakes that gone so stale, that they are actually sour instead of sweet".

rakall · Post by **rakall** » 09 Sep 2009 16:50

Dileep wrote:It is inconceivable that a paper written for peer review would contain obvious glaring flaws that could be pointed out by people from outside the domain.

Now we figure why the NPA Whatshisname called it "Shitty Science". He expected the real radiochemical analysis report, where what he got was this radio spectroscopic analysis. Rather than trying to figure the merits/demerits of this method, he just branded it as "Shitty Science" and tossed it away.

Since this is "analogy season", let me try my hand on that. It is like an american food critic slamming the good old thaTTu dosas as "Pancakes that gone so stale, that they are actually sour instead of sweet".

And then I went to my grand-ma and argued with her that thaTTu dosa should actually be sweet & served with maple syrup.. !!!!!

abhiti · Post by **abhiti** » 09 Sep 2009 17:05

Arun_S wrote:Very well presented news article from Frontline Pokhran row

R. RAMACHANDRAN

The controversy over the yields of the Pokhran-II nuclear tests still rages, with specialists continuing to question the DAE’s conclusions.

Arcticle has great many details...but with all the lingo discussion it abruptly jumps to conclusion that no more tests are needed. If folks never understood why America will GIFT 123 to India then need to consider if it is because America knows about designing nuclear weapons a lot more than India does and if the knowledge that one TN test doesn't get India true TN device and limiting new tests will cap India's nuclear capability was at the heart of it? I have come across no product, engineering or otherwise, for which one test was sufficient. Even simple science lab experiments are required to be repeated and only average values are useful. So I don't really understand the point of people claiming we need to rush into CTBT.

amit · Post by **amit** » 09 Sep 2009 18:24

abhiti wrote:So I don't really understand the point of people claiming we need to rush into CTBT.

Could you be so kind as to point out where exactly people have claimed "that we need to rush into CTBT"?

What is being discussed is whether BARC/DAE indulged in "shitty science" or whether its detractors have indulged in "shitty analysis"'

Please don't toss a Strawman into an already complicated set of arguments.

My request only.

Suneet · Post by **Suneet** » 09 Sep 2009 20:04

deleted

Suneet · Post by **Suneet** » 09 Sep 2009 20:05

IMO
the current situation means our govt. has laid down hopes that our scientists can't produce results which were produced by rest of the world more than 60 years ago. during the end of sino-India war, nehru blinked and signed for arms from US, USSR, Israel... deviating from pompous but hollow non-alignment...
face it, if our scientists cant match rest of the world in pace, we need to buy tech, or we need to get aligned with NATO etc... china is getting cocky, and if world economy dwindles against them, those madheads can resort to anything. though world perceives sino-India 62 war a result of poor, pompous and blind nehru more than chinese imperialism, china can be unprovoked aggressor as well. if we dont have nuclear deterrent against them, we are risking everything.

if our scientstic are indulging in bug passing after a decade, it shows hey are not competent as rest of the world's scientists. but we need weapons to be world class, cant put our soldiers in uneven war again...

ramana · Post by **ramana** » 09 Sep 2009 20:31

Folks you already have the other thread to discuss and make analogies. Dont do it here.
Thanks, ramana

ramana · Post by **ramana** » 09 Sep 2009 21:41

In article I) the diameter of the cavity for POK I is simulated and compared to the measured value. It is also stated to be in shale with a overburden of granite.

In article II) the radius of cavity of S-I is given with a tolerance band. Assume this is in similar material.

Is there a way to relate the yields of POK I and S-I based on these figures which will give an independent assessment without refs to seismic and radio-chem data?

So I would develop a relationship of yield vs cavity radius. When comparing the two events, the ratios will cancel the unknowns like soil etc. Then plug in various estimates for POK I yield and see how S-I varies with it.

Another thing to do is find a relationship which allows calculating the yield for POK Idirectly based on the radius taking into account soil constants for shale. The cavity is in shale only based on the computer 3-D model.
-----------

These two articles are purely Indian based and there are no foreign sources or biases. And there is no radio-chem calculation uncertainities, sesimc wave interference, seismic station location anomalies.
----------

Terhune says the relationship between radius of cavity and yield is

Rc = K * Y^1/3

K = 12 to 14
K is 12 for granite.

We can now calculate the POK I yield and that of S-I.

Sanku · Post by **Sanku** » 10 Sep 2009 00:13

geeth wrote:>>>One must commend R.Chidambaram, Anil Kakodkar and Sikka ji for such fantastic improvement in accuracy of yield estimation using radio-chem. Instead of better accuracy from +/- 7% they increase it 3 times to +/-20%.

Are these errors + / -7% and * / -20% over the SAME data or over DIFFERENT data? Did you fail to notice one is Seismic and the other is Radio-Chemical data?

The error margins are over the total yield, the question is if I use method 1 to determine a total yield of Y1 and have a X% error in the method, and then I do a detailed testing I would expect the yield Y2 now given to have Y% (where y < x) why would I verify my results using a method which has greater error margins than previous method.

It does not make sense.

Bade · Post by **Bade** » 10 Sep 2009 02:00

The possible sources of error in the measurement of fission yield are : assay of radioactivity (5-7%); nuclear data such as half life, gamma-ray branching intensity and fission yields (8%); and the error in integration which arises mainly due to the error in Rc (15%). In the assessment of fusion yield, the sources of errors are uncertainty in the elemental composition of the surrounding rock and its effect on the neutron spectrum used in the Monte Carlo simulations of the activity. The propagation of these errors leads to an overall error on the measured yield which is around 20%. Thus it is concluded that the total yield of the thermonuclear device is 50 + 10 kT.

Adding 5-7%, 8% and 15% in quadrature gives you ~ 20% error estimate for the yield, no ? So what is surprising there ?

Isn't 'r' (typo ?) actually 'rho' for the density in the equation 4 ?

Arun_S · Post by **Arun_S** » 10 Sep 2009 02:03

geeth wrote:Arun_S,

How did you arrive at the conclusion that just two holes were drilled?

Pls tell me where in the paper they mention any more than 2 holes?

From the bolded portions indicated in your BARC quote what I understand is that :

From an earlier position (as centre), they drilled holes on the circumference of a circle 32 m in radius, and obtained many samples. All these samples were found to be homogenous in radio activity, confirming that this earlier position (centre) was not way too off-centre from the actual geometric centre of the cavity. This is again confirmed from an earlier para in the same document

Radiochemical methods of determining the yield of the device involve measurement of radioactivity in the samples retrieved from this region. Several measurement strategies involving estimation of fission and fusion reactants, different fission and activation products and their daughter products are used to estimate the yield. It is also essential that a large number of samples be analysed to obtain the pattern of the distribution of these activities and, wherever necessary, evolve a method of integration to obtain the overall activity produced since any small sample taken in this puddle can hardly be expected to be a true representative of concentrations which can be related to the yield. What is reported here is one such methodology.

Each hole gives a core. Each core is partitioned into samples for measurement considerations, coming from different height. Each of these samples represent a point on the graph in Fig-4, one for a specific sample section coming a particular depth section of the drilled core.

Arun_S · Post by **Arun_S** » 10 Sep 2009 02:08

Bade wrote:
The possible sources of error in the measurement of fission yield are : assay of radioactivity (5-7%); nuclear data such as half life, gamma-ray branching intensity and fission yields (8%); and the error in integration which arises mainly due to the error in Rc (15%). In the assessment of fusion yield, the sources of errors are uncertainty in the elemental composition of the surrounding rock and its effect on the neutron spectrum used in the Monte Carlo simulations of the activity. The propagation of these errors leads to an overall error on the measured yield which is around 20%. Thus it is concluded that the total yield of the thermonuclear device is 50 + 10 kT.
Adding 5-7%, 8% and 15% in quadrature gives you ~ 20% error estimate for the yield, no ? So what is surprising there ?

Isn't 'r' (typo ?) actually 'rho' for the density in the equation 4 ?

Pls read again. What you are saying is applicable to fission yield. I am talking of fusion.

No, my point is they can't take cover of errors due to:

In the assessment of fusion yield, the sources of errors are uncertainty in the elemental composition of the surrounding rock and its effect on the neutron spectrum used in the Monte Carlo simulations of the activity.

to attribute to fusion error tolerance.

My statement was:

So the 20% error in Fusion energy estimate is untenable IMVHO.

ramana · Post by **ramana** » 10 Sep 2009 02:29

The POK I 3-D paper gives measured values of the event. The cavity was 30m on page 6 or 1138 of the Journal issue. The soil is shale which is a hard rock but not granite. Same page. They dont say whether its diameter or radius.

Arun_S · Post by **Arun_S** » 10 Sep 2009 02:30

geeth wrote:>>>One must commend R.Chidambaram, Anil Kakodkar and Sikka ji for such fantastic improvement in accuracy of yield estimation using radio-chem. Instead of better accuracy from +/- 7% they increase it 3 times to +/-20%.

Are these errors + / -7% and * / -20% over the SAME data or over DIFFERENT data? Did you fail to notice one is Seismic and the other is Radio-Chemical data?

Three observations:
1) Radio chem yield estimation is known in industry to be the most accurate method to determine yield.
2) The initial press release of 45 kt +/- 3 (corresponding to 7%)was based on close in sensors (BTW they are not necessarily only seismic, but also sensors that measure more directly)
3) So what do you make of a methodology where the most accurate Radio-chem method of yield estimation is dished out with +/- 20% error estimate. That is many times worse then the error due to other sensors that are supposed to be less accurate (as specified by tolerance of measurement).

Of course each instrument gathers some other types of data for the very same event.In meterology that is given, but all measurements and method result in a given error tolerance.

The results presented by the above paper is like measuring a small block of steel using a big ruler and saying it measures this much within accuracy of +/-7%. And then another person measures the same block using a super duper caliper (with much higher resolution and absolute accuracy) and reporting a number and qualifying it with +/-20% accuracy. Is it difficult to notice a major disconnect?

I am only pointing that out.

Sarma · Post by **Sarma** » 10 Sep 2009 03:21

Two points I would like to make. I am not drawing any conclusions myself from them.

(1) It is curious to note that Sri K. Santhanam is not an author even on a single paper among the series of papers published by the BARC scientists from 1998 onwards. This seems to indicate that he is/was not in the loop as far as the various yield measurements and their techniques were concerned. His only claim to fame is that he was the Incharge of DRDO instrumentation--whatever that means--and the reports that he questioned the yield right after Pokharan-II. This was extensively investigated by the entire Pokharan-II team and was satisfactorily explained to be the result of instrumentation malfunction.

(2) DRDO scientist team has published more than half-a-dozen peer-reviewed papers. Being bred in the scientific community, I was taught to place an innate faith in the bonafide intentions of the authors. Are we to believe that these authors are lying in each and every one of their papers? Second, K. Santhanam, as I said above, is not an author in even one of the papers. So, by the scientific standards, whose words are we to believe? Those of a statement made of the cuff or those of a series of papers in which the authors pain-stakingly follow the scientific rigour? This is the basic question.

Arun_S · Post by **Arun_S** » 10 Sep 2009 05:07

While I may not have published any nuclear paper, but can you or any one show how my reasoning disproving the basis for 20% fusion yield accuracy by reading the BARC paper that assumes that I know just enough of a new college level nuclear physics graduate? And I am only quoting BARC's own paper,

In the assessment of fusion yield, the sources of errors are uncertainty in the elemental composition of the surrounding rock and its effect on the neutron spectrum used in the Monte Carlo simulations of the activity.

and not some NPA analysis/report.

After all all peer reviewed paper have to stand scrutiny of the College level physics and math, and further on the math used in high-school and kindergarten.

Sarma wrote:This was extensively investigated by the entire Pokharan-II team and was satisfactorily explained to be the result of instrumentation malfunction.

Could you tell us more on how this assertion comes from?

You think this paper was peer reviewed, and the peer reviewer had access to the data used to calculate the integral? The same confidential data that is said to be provided to no one else but a closed team of weaponeers?

As an aside, in terms of scientific research ever heard of rampant in-breeding in BARC and the dramatic fall of number of papers published by BARC in leading journals in their trade? I am sure being a researcher you know or can get to know. Word wide the number of scientific papers published in each domain is growing at rapid rate. How does BARC fair in retaining their share of global papers published in leading journals of their trade.

BTW can someone tell me what is the subject/trade that CURRENT SCIENCE can claim as its subject domain? and what is the ranking of CURRENT SCIENCE in the pecking order of trade journals in relevant subject domain?

shiv · Post by **shiv** » 10 Sep 2009 06:29

Arun_S wrote:While I may not have published any nuclear paper, but can you or any one show how my reasoning disproving the basis for 20% fusion yield accuracy by reading the BARC paper that assumes that I know just enough of a new college level nuclear physics graduate?

Arun even if you have successfully trashed that paper it means nothing, and you are not even the first person to do that - as you can see Carey Sublette's paper has already trashed it in 2001. The method itself is highly inaccurate.

I repeat the relevant quote:

Radiochemical analysis is commonly said to be the most accurate means of yield determination. But this statement refers to an entirely different type of radiochemical analysis from what BARC performed in this study. The most accurate method is to determine the percentage of material fissioned by comparing the ratio of fission products to fissile material in a sample,

The method BARC have published to estimate yields is hardly the real method used. Publishing the results of the most accurate method will not be done because (as per Sublette) the design details of the device will be revealed. Neither you nor I have proof that they have not used that method other than the statement by Chidambaram about sampling the glass marbles for analysis that I mentioned earlier.

There is_no_new_information as of today.

Arun_S · Post by **Arun_S** » 10 Sep 2009 06:46

Taking Shiv's assertion at face value, can anyone figure out why heavyweights at BARC publish such papers that can be trashed by scientific analysis of fresh collage graduate?

It pulls down the credibility of the journal and authors; why would people and organizations do that consciously?

enqyoob · Post by **enqyoob** » 10 Sep 2009 06:49

Arun_S says:

After all all peer reviewed paper have to stand scrutiny of the College level physics and math, and further on the math used in high-school and kindergarten.

I agree. So do all political claims. So how do the "S1 fyoozzled" community - and Arun and ramana in particular - explain why there were serious brick-separation cracks in Khetolai village, when the test designers expected S1's effects to be so benign that the only precaution needed was to ask the school-kids to stand OUTSIDE during the testing?

And - bear in mind that the testing team's Logistics Base was even closer to the S1 site than Khetolai was to S1.

Please post your explanation of this. I have been asking this of you several times now...

ramana · Post by **ramana** » 10 Sep 2009 06:58

Because its a war of words between uncle's minions and them. If you note this only uncle's folks who question the yields and occasionally UK folks jump in. Its kabuki. You can tell that by the "papers". The numbers are so interesting it means they are not serious.

Now India holds the cards in the strategic dialog. Till 1998, US could put out feelers alleging India will test and threaten sanctions and what not.Now after the Iraq imbroglio and the meltdown, Indian 'establishment' in and out of office can and will raise the bogey of testing which is more damaging to uncle's new world order with dragon as deputy. After all its uncle's minions who questioned the yields na? Its they who are pressuring India to test. Establishment out of office is being forced to say this.

Now why do uncle's folks want to know more about Indian test? How does it affect them? Shouldn't right with all that stockpile stewardship BS?

---------------
N^3,

I don't know. If you know let me know. Maybe bad surki?

shiv · Post by **shiv** » 10 Sep 2009 07:22

Arun_S wrote:Taking Shiv's assertion at face value, can anyone figure out why heavyweights at BARC publish such papers that can be trashed by scientific analysis of fresh collage graduate?

It pulls down the credibility of the journal and authors; why would people and organizations do that consciously?

I can speculate on why and you will then be able to comprehensively argue that the reasons I state are not good enough. This will only amount to beating about the bush and add no information that what has been published so I refuse to take the bait.

I fail to see why you are so concerned about the credibility of the authors when you have already called RC a liar on this forum. Exactly whose reputation are you trying to protect and why is this concern appearing so suddenly like K Santhanam's u-turn?

Guddu · Post by **Guddu** » 10 Sep 2009 07:28

Arun_S wrote: BTW can someone tell me what is the subject/trade that CURRENT SCIENCE can claim as its subject domain? and what is the ranking of CURRENT SCIENCE in the pecking order of trade journals in relevant subject domain?

It publishes on multidisciplinary sciences. Its impact factor is 0.7 (ie close to a trash journal for science). For a unique scientific experiment (nuclear explosion), its unpardonable to publish in such a worthless journal. In comparison the journal Science has an impact factor of 28. Good science is published in journals of impact factor >5.

Prem · Post by **Prem** » 10 Sep 2009 07:30

ramana wrote: Now why do uncle's folks want to know more about Indian test? How does it affect them? Shouldn't right with all that stockpile stewardship BS?
---------------
N^3,

I don't know. If you know let me know. Maybe bad surki?

Imagine not knowing when you are supposed to be all knowing .

The itch must be becoming rash in Musharraf . Not kowing keep uncertainty , unpredictability going , hense narrowing the space to manipulative manouvering by all the adversaries, near and far. The suspense of peeking into tight Dhoti with wild imagination is dangerous combination to keep NPA ghadhe unbalanced. They played poker again and Indian just moved a chess piece. Funny , Russians are quiet and dont challenge Indians on this.

amit · Post by **amit** » 10 Sep 2009 07:41

I think it's useful to repeat yet again what K Santhanam actually said:

“Based upon the seismic measurements and expert opinion from world over, it is clear that the yield in the thermonuclear device test was much lower than what was claimed. I think it is well documented and that is why I assert that India should not rush into signing the CTBT,” Santhanam told TOI.

The test was said to have yielded 45 kilotons (KT) but was challenged by western experts who said it was not more than 20 KT.

Link

Again see what he's saying. Based on seismic measurements (we all know where or who made these measurements) and expert opinions the world over...

It is pretty clear that he's using NPA's own arguments to say India should not sign CTBT.

Now the valid question is whether KS is acting on behalf of GoI or acting for a section of GoI which wants to ensure that the political leadership gets the message.

However, instead of focusing the debate on the context of KS' statement and CTBT, some folks have used his statement to bolster pet theories of fizzle which surfaced during the nuclear debate.

As Shiv has repeatedly pointed out there is no new data point regarding the tests that have surfaced on account of KS' disclosure. And this is despite incredible claims about KS being the tester, Kalam reported to him during POK II, first hand Ground Zero tourism reports ( N^3 classic

) etc.

In fact independent news sources (MKS for eg have clearly established that KS was not part of the inner circle which is privy to all the data).

It is, was and will be about CTBT. And the NPA, and western scientists will keep on trying to goad Indian scientists with claims of "shitty science" etc in the hope of hitting their pride and getting some classified info out.

JMT

Arun_S · Post by **Arun_S** » 10 Sep 2009 07:47

Guddu wrote:
Arun_S wrote: BTW can someone tell me what is the subject/trade that CURRENT SCIENCE can claim as its subject domain? and what is the ranking of CURRENT SCIENCE in the pecking order of trade journals in relevant subject domain?
It publishes on multidisciplinary sciences. Its impact factor is 0.7 (ie close to a trash journal for science). For a unique scientific experiment (nuclear explosion), its unpardonable to publish in such a worthless journal. In comparison the journal Science has an impact factor of 28. Good science is published in journals of impact factor >5.

Wow !! thanks for that insight. Although I suspected it to be something similar (a few notches more positive).

ShauryaT · Post by **ShauryaT** » 10 Sep 2009 07:47

Does India really need the H-bomb? The best way to end the debate on India’s nuclear arsenal is to sign the comprehensive test ban treaty

Perhaps this is why the Indian Armed Forces, which have consistently asked for nuclear weapons, have never demanded the H-bomb. The outgoing navy chief and the chairman of the chiefs of staff committee, Admiral Sureesh Mehta, endorsed this when he categorically stated that India had already acquired a credible minimum nuclear deterrent, implying (in the author's view) that an H-bomb was not essential for India’s strategic nuclear objectives.

ramana · Post by **ramana** » 10 Sep 2009 07:50

Now that guy is an NPA. Look at his logic and folks want to tar members on this board!

Sarma · Post by **Sarma** » 10 Sep 2009 07:52

Arun_S Sirji: I wasn't aiming my message at anybody in particular. BTW, Brajesh Mishra, in a recent Hindu interview, says that a review was conducted after the tests and it was concluded in that review that DRDO instrumentation malfunctioned.

I know you mean well. I am just a confused and uninformed person.

arnab · Post by **arnab** » 10 Sep 2009 08:03

Just curious - what is the impact factor of journals published by BR? I keep hearing anecdotal evidence of BR being closely folowed etc etc.

Also, I believe KS 'published' his 'analysis' of the fizzle on rediff - what is the impact factor of rediff?

SGupta · Post by **SGupta** » 10 Sep 2009 08:04

The claim is that the yields claimed by the tests are not accurate. In fact they probably are not. Why would India release accurate information regarding its yields? So somebody can verify or calculate yields based and start putting a complete picture of N-devices together. My position would be, let the rest of the world guess and in fact let them guess if my TN device works or not. If someone wants to take a gamble on that, up to them.

India did not release accurate information and there has been deception on the Indian side. Bravo.

Dileep · Post by **Dileep** » 10 Sep 2009 08:20

ramana wrote:Folks you already have the other thread to discuss and make analogies. Dont do it here.
Thanks, ramana

I apologize. I thought this thread replaced the other one. My bad.

Dileep · Post by **Dileep** » 10 Sep 2009 08:28

The cavity size, coupled with the properties of the rock, would give a very accurate estimate of the yield, probably better than the radio-chemical analysis. Why? Radio-chemical analysis works on sample basis, and with the huge counts of atoms split. The cavity is formed by the physical effect, which is the one ultimately going to do your work.

I wonder if the cavity, which lies only a few hundred metres below, could be measured by echo tomography?

vasu_ray · Post by **vasu_ray** » 10 Sep 2009 08:35

all this seismic data and analysis, atleast the exposed part, isn't really sufficient for anybody to transition to a computational world and the more direct measurements will never be revealed, Santhanam's statement never mentions this data which only few have access to

One understands that the radiation spectrum and intensity produced will have a relation to each of the 3 stages of the TN explosion and using similar equipment as to that of detectors in a particle collider one can unambiguously measure the spectrum

the shockwaves lag the initial light from the explosion so the sensors would have seen it before being destroyed, if they can correlate design with observed test data they would be able to make corrections if any, its exact science no?

anyways for politics sake, atleast the debate should be open

shiv · Post by **shiv** » 10 Sep 2009 08:41

Dileep wrote:The cavity size, coupled with the properties of the rock, would give a very accurate estimate of the yield, probably better than the radio-chemical analysis. ?

That is not what the few available articles giving information on the Internet say.

As a non expert I will guess that an expanding cavity during an explosion need not be spherical and indeed will not be so and will have unpredictable dimensions depending on the detailed micro-geology in the area. Furthermore the cavity soon collapses making all estimations approximate.

shiv · Post by **shiv** » 10 Sep 2009 09:06

Arun_S wrote: Others are on the poor quality of the paper is that the author is using cylindrical coordinates system in the equation #4 (that's akin to catching the ear by wrapping arm around the head) instead of spherical coordinates system

About the "cylindrical coordinates" - here is an explanation. But it will not increase accuracy of the method whether you use sphere or chimney IMO - but I only quote from general reading and timepass.

http://www.globalsecurity.org/wmd/intro/ugt.htm

Soon after the detonation, the molten rock around the cavity periphery begins to solidify and accumulate at the bottom of the cavity. As the gas inside the cavity cools and some gas seeps into the surrounding rock, the gas pressure in the cavity decreases to the point when it can no longer support the overburden. Consequently the crushed and sheared rock above the cavity will collapse progressively, especially when the horizontal in situ stresses are low. Over a period of a few minutes to a few hours after the detonation, a tall cylinder, commonly referred to as a "chimney," form. The chimney will propagate upwards until it naturally stabilises. The blocky rubble that accumulates in the chimney void occupies a greater volume (in the range of 20-30% more) than it did in situ. This causes the eventual arrest of the upward propagation of the chimney. The chimney height can be in the range 4 -10 rc , with values near the lower end of this range (5 - 6 rc ) being most common. If the collapse of the chimney material should reach the surface, the ground will sink into to the empty space thereby forming a subsidence crater. Some deeply buried explosions of low yield form cavities that do not collapse to the surface and, consequently, do not create subsidence craters. If the top of the chimney does not reach the ground surface, an empty space, roughly equivalent to the cavity volume, will remain at the top of the chimney.