Great prices on Solarmeter 6.5 and 6.5r on Amazon US

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Claudiusx

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The 6.2 is calibrated to measure wavelengths of 250-320 nm. It can not measure a specific wavelength, it measures all that fall into that range to give you a µW/cm² reading. So as the bulb decays, that reading will get lower and lower as the bulbs output drops.

Gormagon":1wxisez7 said:
Y'all need to put this stuff in layman's terms for those of us who are not geeky can understand it.
The 6.2 can be used to measure decay
The 6.5 can be used to measure decay

However, the 6.5 is better suited for determining basking spot/lamp placement as it is specific for measuring the wavelengths that are more apt to produce vit d3 synthesis in the skin. That is why most professionals now are using the UVI scale as opposed to µW/cm² when it comes to herps.

Dr Francis baines has a good example of it. Her exact quote is on my thread I linked to above, but the jist of it is this: They had been measuring µW/cm² of the sun and getting measurements of around 400 and everything was fine. No sunburns, no skin or eye issues. But, one of their test lamps was exposing things to only 50µW/cm² (8x less µW/cm²) and there were reports of serious eye issues, skin damage, shock and even death in some cases. It wasn't until they did further studies where they realized that even though that lamp was only outputting 50 µW/cm², the amount of super short wavelengths that made up that 50 was extremely high. That's the problem with not having a device that can differentiate between the short harmful wavelengths, and the non-damaging ones.

So, if you were using that lamp, and you went off the suggestion of 200µW/cm² at the basking site, you'd be exposing your dragon to a UVI level of 20! A far cry above what is actually recommend. anything over a 7 is considered to be getting into the danger zone (for beardies or humans).

If that still is confusing, just let me know and I will try to explain it better. But at this point I think we better continue the discussion on the thread I linked above, as we are drifting into slightly offtopic territory :)

-Brandon
 

kingofnobbys

BD.org Sicko
Aaradimian":kdjja36f said:
Gormagon":kdjja36f said:
Y'all need to put this stuff in layman's terms for those of us who are not geeky can understand it. I am not an astrophysicist nor am I a chemist or am I a biologist I'm just a dragon owner that works on a farm.
LOL, sorry about that Gormagon! My inner science nerd sometimes escapes his room. Back to the books, poindexter! :study: :whip:

Basically asking KoN (if he's tested it), when a UV bulb starts going bad, does it reduce just a certain range of the UV light, or all of it at once? If the answer's 'all at once', I was suggesting that either meter being discussed would probably be fine for us to use to make sure our beardies are getting enough UV because both would measure output intensity (flux). But if it does affect certain parts of the range differently, then I understand why he prefers one meter over the other.

Since this old dead thread has been dredged up.

It's the nature of phosphors that the rate of decay is not instanteous , nor is it uniform across all UVA and UVB wavelengths. As Zoo Med found out not so long ago when they changed the phosphor chemistry / composition and suddenly their T5ho tubes were decaying much faster than everyone ( especially their customers) expected.
Of cause one can (and should) ask why they released the t5ho tubes with a different phosphor before having their engineers, chemists and materials scientists at least conduct in house / laboratory tests . Someone really stuffed up and it resulted in a fair bit damage their brandname when customers started noticing their reptiles becoming ill and those with Solarmeters made unexpectedly very poor measurements.
Was there even a recall ? hell no.


The phosphor rate of UV emission decay will not be uniform across all wavelengths , it can concentrated in the UVA or the UVB bands. A meter that is not able to discriminate and give a quanitative reading is going to make it hard to determine how the phosphors are decaying .

So sorry , there is no simple way of explaining this .
 

Aaradimian

Juvie Member
Thanks KoN, your explanation helped. This is actually a similar issue to what was experienced in the old tube TV days with the phosphors "wearing out" then. Depending on the failure mode, you'd get all sorts of color and "luminance" issues with the picture. It definitely varied with each individual tube and the 'fix' was to chuck the old one for a new tube.
 

kingofnobbys

BD.org Sicko
Aaradimian said:
Thanks KoN, your explanation helped. …. {/quote]

Now for a wee bit of science :

While the exact composition and structures of the phosphors is a closely guarded secret . Researchers have destructively extracted the phosphors used and analysed these chemically allowing research laboratories to infer their structures and reverse engineer these.

Some of the UVB emitting phosphors have been analysed and studied in the academic literature .

A likely phosphor formulation has a composition Ca1-xGdxAl2O4 (x = 0.0025–0.09).
PL spectroscopy assessment shows that with increasing Gd3+ concentration, the ultraviolet emission from Gd3+ at 314 nm (6P7/2 → 8S7/2) progressively enhanced.
Gd3+-doped CaAl2O4 phosphors display electron spin resonance signals with the effective g values at g ≈ 1.95, 2.9, and 3.7.
Additional UV emission lines were also observed at the approximate g values of ~2.2 and 5.3.
Gd3+ ion located in the distorted surroundings and experiencing relatively strong crystal field, give rise to low field emission lines.
Distorted surroundings in the present system may result from the nearness of the charge compensator oxygen vacancies.

Others are
LiCaB.O3 :Gd(3+) phosphor ( narrow-band UV-B emission peaking at 315 nm, with excitation at 274 nm).
Y4Zr3.O12:Gd phosphor emission spectrum, upon 274 nm excitation exhibits a well-defined sharp and intense peak centered at 313 nm emitting UV light. The EPR spectrum exhibits several resonance signals with the effective g values at g ≈5.58, 4.33, 3.51, 2.73 and 1.98. From EPR and optical studies, it is observed that gadolinium ions are present in trivalent state in the Y4Zr3. O12 matrix.

Gd is Gadolinium.
Y is Yttrium
Zr is Zircium
B is Boron
O is Oxygen
Li is Lithium
Ca is Calcium

Gadolinium and Yttrium are the components that decay.

Based on this , and the detector response calibrations the better choice is the model 6.2 .
The calibrated response curves of the model 6.5R and model 6.5 are both quite insensitive ( poor ) at detecting the UVB at the phosphor's peak UVB emission wavelength.
 
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