HP I see your comment on vid http://www.how-to-diy.org/sTvH-FiXgntFp8/Homemade-x-rays.html now I'm asking what means _roosterroft_ Walton multiplier? I say you victim of brainless auto censorship algorithm? HP I am so happy you only chilling at The Encampment instead of going after tubes now but I say Encampment is kinda creepy like South Fork Fishing and Hunting Club! I sorry cause I know EFA benevolent and responsible but secret societies just always creep me out! Plz have nice time

 

HP I buy nos Varian G256 potted in B150 housing want to test so apply 50kvp for just instant and see fluoroscope flash very bright, is good! I know you said about easy to damage anode if stationary so I apply 10ma for only 100ms so 50J not thermal stress enough to fracture or pit heavy g256 anode. Also I not apply higher volts because you said about need for self gettering warm up period. I want rotate anode with 60hz but afraid to experiment with leads cause if connect cap and pwr wrong anode spin reverse! I know no harm done so they say but want to treat new tube right first time Now I am asking about stator lead assignments, optimum cap value, how to aproximate anode AV from I and E relationship and self gettering procedure. I know you not answer until return but I say you read here anyway Plz hurry back cause I miss you!

 

but I say you read here anyway

Ya got me!

Well hey! -- Although I'm yet on 'vacation' I wish to assist you with your new acquisition lest that all too familiar species of impatience drives you to inadvertent destruction of same! Owing to 'logistics' I'm having to communicate via 'remote access' via my home system -- A procedure which has not met with unqualified success - Assuming I get this post 'through' please don't count on/expect any further pending my return -- But Yes! I will attempt to 'look in' on a daily basis

But to continue:

Now I am asking about stator lead assignments, optimum cap value, how to approximate anode AV from I and E relationship

I've attached specifications for the tube and housing (inasmuch as I can no longer find same on Varian's site):

The stator info is presented on a table (page 4 of B150H.pdf) -- Please identify stator 'type' and "lead assignments" via DC winding resistances shown on said table! -- In my experience (owing to last minute customization requests of 'power buyers') labeling, and, indeed, even connector wiring, is frequently misleading and occasionally straight up wrong!

Inasmuch as the anode rotor/stator assembly constitute an unloaded (albeit 'high slip') induction motor, maximum/final anode angular velocity is a function of stator excitation frequency.
Should your assembly be equipped with stator type "STD" or "Q" a 60 Hz sine wave will be ideal for your purposes inasmuch as 'over-speeding' will not be possible and you have no requirement of 'fast spin-ups' -- that said, for longest bearing life, it is highly advisable to arrest rotation (via application of a DC 'braking current' to the stator) at the close of each 'session'...

FWIW: The angle of the port to the PSU receptacles ('horns') will vary as per the original consignee's requirements - Most commonly encountered are 90° (as shown) and 0° (corresponding to 'over-table' and 'under-table' applications respectively -- For your purposes said arrangement is of little significance --- And certainly not worth opening and 'repotting' for the sake of trivial convenience!!!

Please note that for anode EMFs >75kV use of a 'split supply' arrangement is mandatory! -- nor can you 'get round' said requirement via 'floating' the housing -- For while the filament supply is an EHT-insulated floating secondary -- the stator PSU is not! For which reason I urge you to implement a split (grounded housing) scheme for all purposes...

afraid to experiment with leads cause if connect cap and pwr wrong anode spin reverse! I know no harm done so they say but want to treat new tube right first time

Very good! Pride in ownership is an admirable quality! --- As to to the consequences of 'back spinning' -- The principal concern is with the torques attendant to braking and 'quick starts' The threads are cut such that braking (imposing the greatest torque) results in 'tightening' of the anode (hence checking 'loosening creep' attendant to 'quick starts') --- I've personally seen several (otherwise) good tubes with their anodes laying loose in the envelope as a result of prolonged reverse rotation (Where's Uri Geller or Stephen Spielberg's Carrie when you need them!?) -- And please! - Don't ask how the envelope survives the 'trauma' of a rapidly spinning, multiple KG anode falling upon it - I dunno - maybe it figures it's gotcha anyway so no need for additional drama --- Seriously though, it happens - and the tubes tend to remain intact! --- The other issue with reverse rotation is that (even new) tubes have been 'run-in' at the factory -- hence it is reasonable to suppose that reversing the direction may result in enhanced bearing wear in an already short-lived bearing design (While powdered AG is about as good as it gets in vacuo - it is, nonetheless, markedly less than an optimal lubricant!)

I know you said about easy to damage anode if stationary so I apply 10ma for only 100ms

Not a good move! - Though, under similar circumstances, I'd have probably done likewise --- Only 10mA? -- I'm guessing you were running the 'small' filament at 'yellow' incandescence (i.e. ~7V)?

In response to your other posts:

HP I see your comment on vid http://www.how-to-diy.org/sTvH-FiXgntFp8/Homemade-x-rays.html now I'm asking what means _roosterroft_ Walton multiplier? I say you victim of brainless auto censorship algorithm?

So it would seem... -- Similar chicanery occurs when such a parser is supplied with the 'venerable' phrase nominative of a domestic feline -- in which case "cat cat" is the result -- Geeeze! Some folks have delicate sensibilities!

FWIW here's a link to the original video/comment:
https://www.youtube.com/all_comments?v=8pFtng-HvTs

I say Encampment is kinda creepy like South Fork Fishing and Hunting Club

Yebut!... -- We're all the way downstream -- So no worries there!

secret societies just always creep me out!

Ya know -- it seems the public conception is that anyone not welcoming -- neigh, embracing -- tourists, hikers, XC skiers, kayakers , snowmobilers, poachers, litterbugs, human torches, thieves, punks, etc... (IOW anyone wishing merely to be left to themselves) is either 'Illuminati material' or an inbred degenerate with designs upon the likes of Ned Beatty --- Seriously, as I have stated many times, I too have serious qualms as regards ('real') property rights (i.e. the 'doctrine' by which American's access to most of America is contingent upon wealth, 'connections', social position, etc...) -- that said, the laws as they stand at this time (right or wrong) do provide for exclusive access to large tracts of land - and I feel the EFA have adhered the 'kinder' spirit of same -- to wit maintenance of a private retreat as opposed to another (Uggg!!!) public park! --- Moreover, we're hardly a secret society! -- It is merely that we've nothing to gain via 'advertisement'...

Plz have nice time

I'll try but don't fancy my chances with no less than three individuals who seem to have something 'critical' to tell me yet can't seem to enunciate it! -- Though my impression is that of amicability - it is my stance that cats seldom steal the tongues of welcome tidings! --- Methinks my reputation as a 'mad scientist' has found me out!

HP I follow over cautious safety program because you payed for equipment and I promised but the absorbed dose I could receive in worst case _IF_ contactor weld on _AND_ watchdog timer crashed would be to primary fuse less than 20ms so at very worst 26.667 RADs full body _IF_ not wear apron _AND_ collimator shutter set full! So I'd _POSSIBLY_ have mild symptoms and _MAYBE_, just maybe, enhance liability to neoplastic disease later in life. I say what of it? As if I'm going to live forever anyway HP don't worry! We have bargain so I won't be pulling a Clarance Dally

Firstly, honesty compels my assertion that your estimates are high as regards dose rate -- While your figures are indeed correct (under the conditions of your setup) at ~ 0.5M from the collimator - said distance is incompatible with full (stationary) body exposure -- IPOF full body (actually head and trunk) exposure would require a distance of (at least) ~1M from the port/ 'splayed' collimator -- then, owing to the increased distance taken with reflective and defractive phenomena, 'field intensity' would be such that absorption would occur at Ca. 1/3 to 1/4 the stated rate (dependent upon energy (or, if you prefer, wavelength [ λ] ) --- But to my point: at the (downward) revised figures the LD50 (4 Gy) would be absorbed in less than 1 second and the LD100 (7 Gy) in less than 1.6 seconds --- Do you really trust that fuse/circuit breaker with those stakes!? Granted, the wiring/transformer would fail and the tube would melt - but you would be 'toast'! - Worst of all you'd have plenty of time (perhaps weeks) to dwell upon it! - and I assure you, you'd long for death before it arrived! --- Moreover, at risk of presumption, I assert that your strength of character is such as to preclude 'preemption' of even so lamentable a fate... Unnecessary drama? Perhaps, howbeit absolutely accurate! I have witnessed illness and death from ARS (acute radiation syndrome) - I know what I'm talking about! -- Safety tends to be so tedious a topic that it is often necessary to remind people what's actually at issue!

So I'd _POSSIBLY_ have mild symptoms and _MAYBE_, just maybe, enhance liability to neoplastic disease later in life. I say what of it? As if I'm going to live forever anyway

Spoken like a true "20-something"!!! --- Might I suggest that your future is not yours to gamble with? It belongs to the future 'Aleph' - whom I expect will thank me for this some day!

HP don't worry! We have bargain so I won't be pulling a Clarance Dally

I'm pleased to hear it! -- I'd be even more pleased if you practiced safety for its own sake!


All the best
HP

 

HP I know you're on vacation but what I say now you want to know! Some creep or creeps sending accusing email to my google mail account saying you and I are two of five egos of same poster employed by AAC parent company to study sexism and treatment of women in technical environment! I know would be funny but I don't like being called a liar! Now I don't know who to trust (except you) cause AAC insiders only others who have my addy cause how I registered. You said when had just similar problem that someone from AAC admin contact you worried you were being harassed? I think would be right contact for this? Could you Plz tell me how to see _headers_ from emails? HP I want say before you do that I really know that almost all AAC members and inside staff are sincere and honest but a few bad apples can rot the whole barrel I can't help thinking is backlash for posting on chat forum! I starting to think young and female people not universally welcome here! Plz don't worry! I'm not angry you say I talk like typical 20 something, you right about how I had stupid attitude about safety and short shortsightedness for my health! What mean is I feel like they see us as interlopers and me as upstart as well HP thanks for the Specs! I download them so if want to remove them, all clear! I thought odd in good way they had no views so whatever else wrong here at least low busybody count! I post all this to private conversation thread too!

 

Some creep or creeps sending accusing email to my google mail account saying you and I are two of five egos of same poster employed by AAC parent company to study sexism and treatment of women in technical environment!

Yet another side of the same multidimensional counterfeit coin! --- My 'love letters' claimed I was a puppet of a member of the editorial staff on a mission to ferret out 'orange skeptics' --- go figure!

I know would be funny but I don't like being called a liar

My sentiments exactly!

Now I don't know who to trust (except you) cause AAC insiders only others who have my addy cause how I registered.

I have absolute confidence in AAC's staff! --- Rest assured! SQL data structures are childishly easy to hack, anyone with even modest expertise or willing to offer a small sum to another possessed of such expertise could readily retrieve your registration data -- Having operated two sites and been party to operation of several others I can assure you there is no such thing as security where SQL is concerned! --- The foregoing being one of many reasons I refuse to provide personal information to any unpaid online service -- and commonly employ personal acquaintances as 'straw buyers' for eBay, et al... All of which is to say, IMO you may and, where appropriate, should confide in the staff...

You said when had just similar problem that someone from AAC admin contact you worried you were being harassed?

Indeed, however, again I feel you may trust any member of the staff --- Trouble is, inasmuch as the heckling is 'off list' I doubt it will be deemed an 'AAC problem' - granted it (i.e. the suggestion that management are conducting 'undercover operations') could be regarded as (mildly) defamatory to the site - even so I doubt they'll be interested in pursuit of such 'peripheral matters'...

Could you Plz tell me how to see _headers_ from emails?

Sure thing:
Having opened the offending message:
-Click on the 'More button' (∇ on right side of message)
-Then select "Show Original" in the resulting menu

I can't help thinking is backlash for posting on chat forum!

I hear you! - The timing is curious

My advice is that you send a single response stating your intent to publish the headers on these fora (and elsewhere) should any further messages be forthcoming -- make certain to include the phrase: "therefore no expectation of privacy exists"
Then you must follow through upon receipt of any further offending correspondence! --- Aleph, I've a very good idea who the 'creeps' in question are! - and have no problem with 'throwing them to the wolves' whatever should they continue to trouble you...

Moreover, should the missives contain threats of violence, extortion or otherwise 'actionable' material - you are advised to contact the appropriate law enforcement agency immediately! --- The interstate/international nature of email significantly 'enhances' the severity of their criminality...

I starting to think young and female people not universally welcome here

Well... Nobody is universally welcome anywhere! But to the spirit of your point: While there is an undeniable (yet quite natural) 'generation bias' I'm bound to say I see no 'gender bias' whatever...
First off let's be careful to distinguish the 'email hecklers' from 'honest detractors' -- outspoken folks don't make 'anonymous', private accusations/insinuations - if they have something to say -- they say it! - therein lies the 'silver lining' of rudeness (to wit: honesty) FWIW Here's my take on our 'on list detractors':

--My formality is mistaken for pomposity whereas your 'style obfuscation' is mistaken for duplicity or 'gaminess' --- In any event our respective styles 'get on their nerves' -- Tis a matter of "can't please everyone" --- More generally, despite our professional standings, it must be confessed that our approach to this site (which being largely comprised of professionals) is rather like that of 'hobbyists' (e.g. EHT, X-Rays, particle physics, quantum computing, etc... in addition to copious off topic discussion) - moreover it is quite natural that older, more experienced, individuals may look upon us as 'kids' even as I often (inadvertently) address you...

On the other hand, there would seem to be but two (barely) plausible 'profiles' as regards the 'emailer{s}'
1) Someone very unhappy with recent changes to the site who genuinely believes in their own 'narrative' of persecution by a member of the editorial staff...
2) Someone wishing to discredit the editorial staff via accusations of duplicity -- and finding us to be convenient 'scapegoats' owing to our unenviable status as 'high profile' members of nascent tenure.. (i.e. Broadly speaking - we're 'seen' but largely unknown, and, hence, prey of suspicion)...

you right about how I had stupid attitude about safety and short shortsightedness for my health

I'm pleased to hear it! X-Radiation (and, indeed, all forms of energy) is your friend! - Howbeit, much like the spirit in a bottle (Um... as in a 'Gennie' - not ethanol), 'all powerful' but absolutely obliging up to and including your dissolution -- if that's what you ask of it (inadvertently or otherwise) -- Sadly, unlike Microsoft, it never asks: "Are you sure..."

I download them so if want to remove them, all clear! I thought odd in good way they had no views so whatever else wrong here at least low busybody count

ALeph! What part of "public fora" Don't you 'get'??? --- Those files are there for any who wish to view them! - I doubt Varian will 'mind' so long as no one is charging for same --- The lack of 'hits' no doubt owes to the narrow interest in the subject on these fora AND/OR to the (quite understandable) dubiety with which many regard downloading files from unknown sources... --- In any event viewing/downloading the files by anyone is IN NO WAY objectionable!

All the best
HP

 

Me, I'm still trying to figure you two out. And why you wanted this thread in off topic. But I'm enjoying the show and (figuratively) munching popcorn.

I suspect if I was doing a how to on a high voltage high wattage power supply I would have it done in 5 posts, with pictures.

 

And why you wanted this thread in off topic.

As regards the last two posts - You'll have to ask Aleph about that -- If it were me, it would be to put the offenders 'on notice'

Or do you mean, more generally, why post the tutorial/ EHT discussion here? --- That was my 'bright' idea -- too much off-topic content for 'prime time'
FWIW I plan on moving the tutorial to 'Projects' if I ever manage to finish it!

I suspect if I was doing a how to on a high voltage high wattage power supply I would have it done in 5 posts, with pictures.

Enviable indeed! --- I'll be lucky to get it done with lotz and lotz of posts and more than 50 images -- and that's merely 'prepping' the transformer...

But I'm enjoying the show and (figuratively) munching popcorn.

It's nice to be (kindly) noticed!

Best regards
HP

 

HP thank you! I follow your advice! I forwarded header to your E but will not show anyone else unless more emails show up. I've also sent warning like you said. You made me feel much better about all this! Now I answer your first post
You said

The stator info is presented on a table (page 4 of B150H.pdf) -- Please identify stator 'type' and "lead assignments" via DC winding resistances shown on said table!

Based on all that mine is STD and correctly wired

You Said

Inasmuch as the anode rotor/stator assembly constitute an unloaded (albeit 'high slip') induction motor, maximum/final anode angular velocity is a function of stator excitation frequency.

I see Max AV for 60hz is 3600 RPM (which is stupid way of saying 377 radians per second) That good cuz AV not exceed 419 Rad/sec

You Said

it is highly advisable to arrest rotation (via application of a DC 'braking current' to the stator) at the close of each 'session'...

I know they coast for up to hour when not stopped but how much current for braking?

You said

FWIW: The angle of the port to the PSU receptacles ('horns') will vary as per the original consignee's requirements - Most commonly encountered are 90° (as shown) and 0° (corresponding to 'over-table' and 'under-table' applications respectively --

On mine sockets face same way as port so 0 degrees, that's why I got mine for just $3,000! Supply house say not so much call for that form and not bother with taking apart and potting again!

You said

Please note that for anode EMFs >75kV use of a 'split supply' arrangement is mandatory!

I figure as much anyway cause grounding mesh on power cables but for now I using that mains transformer have ma meter between neutral ends of 75kv windings plus movs to grounded case from meter. I looking forward to when you have time to assist me to build hf PSU!

You said

Where's Uri Geller or Stephen Spielberg's Carrie when you need them!?

Ha ha! You saying psychokinesis good for more than warp cutlery and pay back bullies! Just screw puck back onto shaft and good to go another 10,000 hours!

You said

I'm guessing you were running the 'small' filament at 'yellow' incandescence (i.e. ~7V)?

Not sure what voltage. I preset filament variac for pale white when seen through port window so sure of enough emission for when apply 50kv but not so much current to damage anode. When I do 100ms cycle inrush meter record 9.87ma

You said

Similar chicanery occurs when such a parser is supplied with the 'venerable' phrase nominative of a domestic feline -- in which case "cat cat" is the result -- Geeeze! Some folks have delicate sensibilities!

Stupid thing is when people say vulgarity censorship for benefit of children I say if person put marble in jar every time he/she cusses up to the age of 18 then start removing a marble with each expletive they not empty that jar if live to 1,000! Except stevedores and military personnel who empty it by evening of their 18'th birthday

You said

Yebut!... -- We're all the way downstream -- So no worries there!

Ha ha! Anyhow Two Harbors already flooded by 32,000 Miles^2 of aqua pura!

You said

it seems the public conception is that anyone not welcoming -- neigh, embracing -- tourists, hikers, XC skiers, kayakers , snowmobilers, poachers, litterbugs, human torches, thieves, punks, etc... (IOW anyone wishing merely to be left to themselves) is either 'Illuminati material' or an inbred degenerate with designs upon the likes of Ned Beatty

Ha ha! Poor old Ned! I never understand redneck cracker Ned accepting a victim role I like him much better in Dying Room Only, not as much character work!

You said

I'll try but don't fancy my chances with no less than three individuals who seem to have something 'critical' to tell me yet can't seem to enunciate it! -- Though my impression is that of amicability - it is my stance that cats seldom steal the tongues of welcome tidings!--- Methinks my reputation as a 'mad scientist' has found me out!

Clever as you really are you sure can be dense sometimes! I mean I not even there but pretty sure I know what's up and is nothing to do with mad scientist reputation!

HP I say you relax enjoy your vacation! I don't need answers right away

 

I suspect if I was doing a how to on a high voltage high wattage power supply I would have it done in 5 posts, with pictures.

Kewl isn't it? I ask question about salvage ferrite cores now I'm HP's protege! So like HPP

 

HP I say you relax enjoy your vacation! I don't need answers right away

Oh... what the hey!

I forwarded header to your E

Got it! --- Seems we have the same 'fan club' --- Now to see how they receive our latest 'newsletter'!

I see Max AV for 60hz is 3600 RPM (which is stupid way of saying 377 radians per second) That good cuz AV not exceed 419 Rad/sec

--Emphasis added--
Aleph! You can have no idea how pleased I am to encounter another appreciative of sane units! -- Indeed! 'Radians per second' is far and away the optimum unit of angular velocity, and, more generally, frequency of continuous functions (at least) -- Revolutions per second (à la Hertz) is bad enough! - Revolutions per minute is a cumbersome abomination! --- I think I'll never understand the adoption of 'Hertz'? Apparently someone 'back yonder' was enamored of reading and writing "2π" at every opportunity!!! --- I'll say it again - it is a delight to communicate with an intelligent, independent thinking individual!!! -- No need to 'censure' my 'effusiveness'! - perhaps my favorable appraisal of you is down to a cognitive bias whereby 'like minds' approve of each other?

Based on all that mine is STD and correctly wired

Indeed! The 'standard' stator is most commonly encountered -- As is 'default' wiring!

I know they coast for up to hour when not stopped but how much current for braking?

Inasmuch as protraction of MTBF is paramount in your application - my advice it that you bring it to a gentle halt (Spec. Full AV to stationary in no less than 5 seconds) -- Some experimentation will be required to arrive at a precise current 'figure'...

that's why I got mine for just $3,000

Very good! - You strike a hard bargain! At $15K you'd have got your money's worth -- At $10K it would've been a rare bargain -- Less than $5K is phenomenal - regardless of housing orientation!

I figure as much anyway cause grounding mesh on power cables but for now I using that mains transformer have ma meter between neutral ends of 75kv windings plus movs to grounded case from meter

That, of course, is the classic dual symmetrical secondary arrangement -- Inasmuch as it is what the vast majority of (medical and, hence, ubiquitous) radiography equipment 'expects' - best 'stick with it'

I looking forward to when you have time to assist me to build hf PSU!

Pleased to hear it! -- Apologies for my dilatory progress on that 'front'!

Ha ha! You saying psychokinesis good for more than warp cutlery and pay back bullies! Just screw puck back onto shaft and good to go another 10,000 hours!

FWIW: Granting the reality of the phenomenon for purposes of discussion, I doubt it would 'work' in a vacuum -- seems similar manifestations are upshot of induced "standing pressure waves" à la: http://amasci.com/weird/unusual/e-wall.html

Not sure what voltage. I preset filament variac for pale white when seen through port window so sure of enough emission for when apply 50kv but not so much current to damage anode.

If it works, it works! --- Utilitarian though it may be! --- 'Tho I daresay you might find that technique 'challenging' applied to a mammography tube!

I say if person put marble in jar every time he/she cusses up to the age of 18 then start removing a marble with each expletive they not empty that jar if live to 1,000!

AB-SO-LUTE-LY!

Except stevedores and military personnel who empty it by evening of their 18'th birthday

Within 5ns following the first stroke of midnight the morning of their birthday, more likely! -- Then too such a jar would need accommodate several solar volumes!!!

Ha ha! Anyhow Two Harbors already flooded by 32,000 Miles^2 of aqua pura!

Along with MY tubes for another 8 months!

Clever as you really are you sure can be dense sometimes! I mean I not even there but pretty sure I know what's up and is nothing to do with mad scientist reputation!

Care to expand upon that? If you're implying they're 'stooging' for loans - think again! --- This IS the EFA we're talking about! - And lord knows my presence here owes far more to family history than to anything like wealth!

OBTW -- There's no need to preface every quotation with "You said:" --- While I hesitate to label said practice redundant and goofy -- the facts remain!

All the best
HP

 

HP I have quick question for now but more for later when time allow

You said (I sorry, old habits)

'Tho I daresay you might find that technique 'challenging' applied to a mammography tube!

You mean cause mammo tube beryllium port window opaque for visible radiation?

 

You mean cause mammo tube beryllium port window opaque for visible radiation?

Correct - Interestingly, although beryllium is quite opaque to visible light (Ca. 1.8 eV - 3.1 eV) it is significantly more radiolucent than glass above ~ 10 keV...

Best regards
HP

 

HP sorry to be so hurried but here's another quick question
I can't find explicit answer so thinking about it I am saying radiolucency of substance to given energy EMR depend on unoccupied atomic energy level _shells_ Right? So is how Hertzian waves from like radio transmitter shine through optically opaque walls and organic matter like living tissue with varied degree of attenuation but the higher energy rays of visible light totally blocked by reflection or absorbed? So I understand how highest energy EM rays like xray and gamma ray transilluminate all substance cause no atoms have electrons at so high energy level. Now I am asking why not to use hertzian rays for med radiography cause easier to generate efficiently and less health issues? I know flea power 100MHz xmtr transilluminate human body no problem. I think answer is that huge wavelengths don't allow resolution but is not easy to prove in mind. I say med xray radiography for two purposes: 1 inspect for damaged tissues or foreign objects and 2 inspect for diseased (which means abnormal) tissues, so all told is really just density study. Now you see what I mean about better to study for living and practice for fun? No matter how much education in classroom and field one who diagnose and, if lucky, can _repair_ is still just glorified technician! I know is very important for altruistic reason but stagnant and unsatisfying HP I not malcontent just more tired than should be at my age!

 

Doughnut ,nah...can't be,..no onfession.

 

Doughnut ,nah...can't be,..no onfession.

Ok, I'll play, what's an 'onfession'? I would have assumed you meant 'confession' but that doesn't seem to 'help' ---Perhaps you could do with some coffee with those doughnuts?

With friendly intent
HP

 

thinking about it I am saying radiolucency of substance to given energy EMR depend on unoccupied atomic energy level _shells_ Right?

'Unadorned' but essentially correct!

is how Hertzian waves from like radio transmitter shine through optically opaque walls and organic matter like living tissue with varied degree of attenuation but the higher energy rays of visible light totally blocked by reflection or absorbed?

Again, correct! But with the qualification that electromagnetic 'reflection' is descriptive of two, essentially distinct, phenomena;
-Re: Conductors: induction of electric currents with corollary re-radiation...
-Re: Dielectrics: 'wave dynamics' -- Spec: reflection owed to index boundary{s}...
Actually, said phenomena aren't so disparate as might seem apparent via causal consideration -- but there it is

So I understand how highest energy EM rays like xray and gamma ray transilluminate all substance cause no atoms have electrons at so high energy level.

Correct, although some degree of attenuation will occur (in inverse relationship to energy), absolute opacity is (theoretically) impossible much above Ca. 10 eV...

I am asking why not to use hertzian rays for med radiography

I think answer is that huge wavelengths don't allow resolution

Correct! In addition to the fact that tissue opacity at said energies is dominated by many factors apart from density alone...

but is not easy to prove in mind.

Hint - Think nodes, anti-nodes and intervening distances thereof...
(Note, however, that the notion of 'standing waves' per se isn't especially germane to the concept at hand)

I say med xray radiography for two purposes: 1 inspect for damaged tissues or foreign objects and 2 inspect for diseased (which means abnormal) tissues, so all told is really just density study.

Agreed if, as per your stipulation, said statement is confined to Roentography...

I know flea power 100MHz xmtr transilluminate human body no problem.

You've really got to cut down on those wireless microphones! Lithium batteries are bad for the digestion!

Now you see what I mean about better to study for living and practice for fun? No matter how much education in classroom and field one who diagnose and, if lucky, can _repair_ is still just glorified technician! I know is very important for altruistic reason but stagnant and unsatisfying

What can I say? You know where I stand on this - to wit: If you are unhappy you are advised to 'cut your losses and run'!!! -- Your mention of 'altruism' tells me someone (I can well guess who) is attempting to 'guilt you' into following an unrewarding course! Life is far too short for such BS! -- As (I hope) you know, I'm more than happy to discuss this with you at length - For obvious reasons, however, meaningful discussion (i.e. beyond generalities) requires a private format...

HP I not malcontent just more tired than should be at my age!

...and that's no way to have to be! -- We need to talk!

All the best!
HP

 

Wouldn't radio frequency "cook" tissue at close distances?

 

RF can cook you. Microwave ovens were called radar range at one time.

You will see a magnetron in microwave ovens.

 

Hello! And thank you for your posts!!!

Wouldn't radio frequency "cook" tissue at close distances?

RF can cook you. Microwave ovens were called radar range at one time.

Indeed! High-level electromagnetic radiation of any wavelength/photon energy will produce significant heating whether by molecular excitation (i.e. dipole rotation) or direct induction upon absorption...

That said, heating is not a significant factor at the power levels attendant to medical imaging -- to illustrate this please consider the following:

A rather high dose radiographic exposure might operate the tube at 80kV (Min λ=15.5 pm) @ 10mA (Hence 800W input) for a 50ms exposure --- 'Factoring in' an (optimistic) efficiency of 1% yealds a total Roentgen output = 0.4J of which less (typically much less) than 10% will be absorbed by the patient, hence a high estimate of 40 mJ total absorbed energy. --- Or ~ 66 mR dose for full body exposure of a 62 kg human...
Note: For clarity, a 'zero-ripple' anode supply was assumed in the above...

Similarly, as per @Aleph(0), a very low power (e.g. 5mw [5uJ per ms]) wireless microphone (λ=3m) readily transilluminates the body sans measurable heating...

By comparison a typical RF heating grade magnetron (λ=12 cm) (as, for instance, type 2M210) is designed to produce an average continuous output of 1KW (i.e. 1J per ms) when driven to Spec...

My point with all this 'apple and orange slinging' is merely that, as regards medical imaging, heating is not the point!

As an aside, RF (i.e. 'Hertzian') heating is extensively employed in diathermy...

Best regards -- and again, many, many sincere thanks for your interest!!!
HP

 

Short and hot,I just micro waved some food.....I put hot sauce on every spoon

full as I read post.