Large area detector for X-rays--- make money online

I built a large area detector that is sensitive to X-rays and will be used in an upcoming project. The detector is constructed from a "Lanex Regular" X-ray intensifying screen, and a Hamamatsu R6094 photomultiplier tube (PMT).  The PMT amplifies the light from the intensifying screen which is emitted when an X-ray strikes the screen. The area of the screen allows it to catch many X-ray photons created by backscatter. The PMT is setup with a simple 100K

resistor between the anode and ground. A 1V output corresponds to a 1 microamp anode current. I'll probably add a very simple opamp circuit to this, and then pipe it into an A/D converted for digitization.

hi everyone I thought I'd show you the

latest thing I've been working on this

is a large area x-ray detector so last

time I showed you my x-ray tube setup

and together the detector and the tube

will form a part of an imaging system

I built this detector by taking apart an

x-ray image intensifying cassette so

these devices are used by medical

personnel to image parts of the human

body so they put a piece of standard

film inside the cassette and the

cassette has two phosphor screens inside

that are pressed up against the film and

then when the x-rays hit the cassette

the phosphor is emit visible photons

after being struck by x-ray photons and

it's actually those visible light

photons that expose the film so it's

possible to expose film directly with

x-ray photons but it's not a very

efficient process so the phosphor xur

would actually get the job done so this

was a large cassette it was a LAN ax

regular and I'm not exactly sure what

phosphor lanex actually is I've done a

fair bit is searching it's green and the

decay time is pretty quick from what

I've been measuring so far and I'll show

you later so to build the whole detector

I took the screen out and then pasted it

inside a coroplast pyramid that I built

so coroplast is just corrugated plastic

that I bought at tap plastics and then

put all the joints together with gaffers

tape

I made a small plastic flange on the

lathe and then taped that in as well and

then screwed in the photomultiplier tube

mount into that the photomultiplier tube

is a Hama Matsu are 6:09 for tube a

fairly standard model and also the same

one that I used in my electron

microscope the reason I chose this one

is just because they're they're

relatively easy to find on eBay and I

already had experience using one in the

SEM project the maximum voltage for this

tube is 1500 volts so initially I was

running it at about a thousand figuring

that I didn't really need any more gain

but later I cranked it up to 1,400 volts

and was getting quite a bit more signal

out of it initially I thought that this

detector didn't find any background sort

of cosmic rays or x-rays but actually

that's not true I just didn't have it

wired quite right so after fixing all

that up the amount of background

detection is actually quite high and you

can hear it by the clicks on this audio

of monitor right here I configure the

oscilloscope to output the trigger

signal out this calibration BNC port and

then plugged a really small low cost

audio amplifier into that so every time

the trigger every time the scope

triggers it sends a click to the audio

amplifier I also set up the system with

the x-ray tube pointing out into the

shop ie in the same direction of the

detector is facing and then turned on

the tube with a little LED aperture in

front of it and measured the signal on

the oscilloscope and was easily getting

a volt or two just from the amount of

x-ray scatter coming back from random

items in the shop I have the photo

multiplier set up in a very simple

configuration with just a 100 kilo ohm

resistor between the anode and ground so

for the amount of current that comes out

the anode on the tube a voltage will be

created just based on the 100k on

resistor there and I have no filtering

setup so the only amount of capacitance

here is just what's inherent in the tube

in the measuring device ie the

oscilloscope what's interesting is I can

set the trigger level on the

oscilloscope two different levels and

then only

look for pulses of a certain height and

it seems that the decay time is on the

order of 50 microseconds right now the

scope is set to 50 microseconds per

division so you can see that the trace

is pretty much gone within 50

microseconds so maybe the decay constant

is is more like 20 or 30 or something

like that the reason that I needed

detector of this much area is because

the backscattered of x-rays are low

intensity and also spread out so for

this imaging application the back

scatter is going to cover a very large

area but it's fairly low intensity so

using a small detector like a Geiger

Muller tube is not effective it's much

better to have a larger area detector

okay I'll keep you posted on this

project see you next time byeTop Paid Keyword :  earn cash online, google make money from home, earn money online without investment by clicking ads, free earn money website, online money making jobs, earn money online without investment by typing, online work for money, best online earning sites, make money online with google, online earning websites, money making websites, online earning websites for students, invest online and earn money, best online money making, online money income, view ads and earn money without investment, earn money online by clicking, online money income site, money earning sites, online earning sites, best website to earn money, free money earning sites,