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Seeking referee-like comments on neutron detection technique in linked paper

by pdxjjb
Tags: lenr, neutron detector
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pdxjjb
#1
Nov7-12, 08:35 PM
P: 14
Hope mods will allow this. Seeking comments on neutron detection techniques described in the linked paper. Authors are affiliated with China Institute of Atomic Energy, Beijing. This is a LENR paper with no theoretical content. Full text is free to download.

http://iopscience.iop.org/0256-307X/29/11/112501

Jeff
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mfb
#2
Nov8-12, 07:46 AM
Mentor
P: 11,580
I am not an expert, but here are some things which confused me in the paper:

Because of the difficulty of detecting low-level neutrons and the infrequent neutron-production from nuclear reactions
Infrequent? Are there nuclear reactions which produce neutrons sometimes, and sometimes not?

However, positive results were also reported.
Not really convincing. If you try, you can find positive results for every crap. The question is how many (sensitive) negative results there are.

Measurement of neutrons in low-energy nuclear reaction
(LENR) requires a particular care and expertise.
Are there any scientific measurements which do not require that?

Therefore, each individual
neutron burst must be evaluated to determine
whether its origin was electronic noise, environmental
gamma-rays, cosmic-ray background, environment
neutrons, accidental artifact noise or a legitimate signal.
Trivial, if done automatic or with statistical methods. If not, it is problematic and you should explain this.

Observation of nuclear products, such as neutrons,
protons and tritium in metal hydride (deuteride)[7−9]
will be helpful to study the mechanism of LENR
Helpful? I think the observation of nuclear products is required to observe nuclear reactions.

The detector has a high neutron detection efficiency
and a good ability to reject ��-ray background
and eliminate electrical noise.
I think you should introduce the detector design first before talking about performance details.

The neutron detection efficiency
Where are the neutron detectors, and how do they work? You did not explain this. Just filling 3He in a tube is not enough.

Uranium (238U) metal machine-chips (about 10 g) were used to prepare the uranium deuteride sample.
Pure U-238?

You could add some sketch of the Ti/D-foils.

Each run lasted about 20 to 50 h, or about 2500 to 6500 cycles. The period of a cycle was 30 s.
Cycles of what?

Figure 2 should get error bars.

the neutron production rate is calculated to be 0.16 neutrons/s, or 0.88 counts/s
I think that should be 0.088 counts/s.

The average random count rate for the uranium oxide sample was measured to be (1.971▒0.03) counts/s; a value of (0.26▒0.03) counts/s greater than the background value.
If you calculate the difference between two values with 0.03 uncertainty, the resulting uncertainty is not 0.03 unless you have some correlation (which I would not expect here, if you have that you should explain it).

The results of time-correlated neutron counts versus
The position of that text at the bottom of the page is a bit unfortunate - probably TeX-induced, and might change with text edits.

in two background runs are given in Fig. 3. The results show that the intensity and frequency of neutron bursts have irregular variations.
Obvious for cosmics-induced background.

The frequency of the large bursts (neutrons
larger than 30) is about 1-05 bursts per day
1-05?

and the time intervals between two individual bursts are larger than 2 h.
Why? I don't see a reason why cosmic rays could not give several bursts within two hours. It is rare, so what?

Do your measurement cycles influence the measurements in some way? In figure 5, you recorded 8 bursts within 7 minutes, but those bursts had a length of ~64Ás, right?

No cascade neutron-burst emissions are observed for either of the control samples.
Both in figure 6a and 6b I can see bursts which are very close together. They seem to consist of 2 or maybe just 3 bursts each, but they are so close that they look correlated in some way.

The burst sequences in the deuterium samples are so rare that they might occur in the control samples as well, and you were just unlucky to miss them (because none happened during your measurement).

After accidental artifact noise and cosmic-ray sources are ruled out
Where did you do that?

and may originate from a nuclear reaction occurring on the metal surface with a micro-nanometer size,[7,17] but do not occur in the bulk materials and the whole surface
Based on what?

On the other hand, random neutron emissions are not observed in this work.
Random in which way?

In general: If you expect something based on deuterium, what happens if you use regular hydrogen instead?

I am not convinced that something happened based on deuterium. A control sample with protium would help, and longer measurement periods to see more burst sequences (or no burst sequences for a longer measurement period in the control measurements).
pdxjjb
#3
Nov8-12, 11:31 PM
P: 14
Thanks for your comments.


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