Search found 1303 matches

by John Futter
Sat Oct 24, 2020 6:22 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Portable XRF detector window repair
Replies: 11
Views: 1311

Re: Portable XRF detector window repair

I use a wad cutter to cut foils
Be is used as it is the first stable (sort of) metal in the periodic table ie low Z so low energy gammas / x-rays can go throught it
by John Futter
Thu Oct 22, 2020 9:35 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Portable XRF detector window repair
Replies: 11
Views: 1311

Re: Portable XRF detector window repair

I do not understand
I put up 15micron thickness solution over your 13 micron measurement
and you need 120mm when you said originally 13 microns

or is the detector nearly 5 inches in diameter --i doubt\\

please clarify!!!!
by John Futter
Wed Oct 21, 2020 6:02 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Portable XRF detector window repair
Replies: 11
Views: 1311

Re: Portable XRF detector window repair

use new Be foil
http://www.goodfellow.com/catalogue/GFC ... V2hvddblfZ
BE000210 looks right.
Be careful it is not good for you
you need the Be foil to keep it light tight and to remove the low energy spectrum (noise)
by John Futter
Tue Oct 20, 2020 12:37 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: My preamp design
Replies: 1
Views: 443

My preamp design

Couldn't put the schematic up in the FAQ section so here it is


Protel Schematic.pdf
(18.33 KiB) Downloaded 57 times
by John Futter
Tue Oct 20, 2020 12:34 am
Forum: FAQs: Neutron - Radiation Detection
Topic: FAQ - Roll your own preamp (Richard Hester design)
Replies: 13
Views: 1235

Re: FAQ - Roll your own preamp (Richard Hester design)

I'll put up my design It is a bit more than a preamp as it has post gain / shaping and a discriminator or lower window output to remove low energy pulses or noise for counting modes. The analize output is suitable for direct connection to a MCA It uses a cascode at the input to mitigate gate capacit...
by John Futter
Mon Oct 19, 2020 10:50 pm
Forum: Images du Jour
Topic: Germanium Sputtering in the new Reserach Facility
Replies: 11
Views: 1882

Re: Germanium Sputtering in the new Reserach Facility

as promised a few pics of a Ge target that got a little hot
Ge_Melt1.jpg
Ge_Melt2.jpg
Ge_Melt3.jpg
Ge_Melt6.jpg
by John Futter
Mon Oct 19, 2020 6:21 pm
Forum: Files
Topic: Photodiode Pulser Circuit
Replies: 3
Views: 5622

Re: Photodiode Pulser Circuit

I do not know about the original file but I use this one to test SPIMs and PMT's
photopulser.pdf
(2.2 MiB) Downloaded 36 times
Note it uses a very high voltage to get the necessary dI/dT through the blue LED
by John Futter
Thu Oct 15, 2020 6:18 pm
Forum: Images du Jour
Topic: Germanium Sputtering in the new Reserach Facility
Replies: 11
Views: 1882

Re: Germanium Sputtering in the new Reserach Facility

Dennis my sputtering system at work uses a 20kV 2mA argon beam to ablate a target held at 45 degrees to the beam this then sprays the ablated onto rotating catchers. Benefit of this system is the ions arrive with 10 -100eV of energy so chemically bond to the receiving surface. Your sputter coater is...
by John Futter
Thu Oct 15, 2020 6:05 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Cooking some cake
Replies: 9
Views: 918

Re: Cooking some cake

All covered by IAEA rules that most aligned countries have signed up to

NORM = naturally occurring radioactive material is exempt unless efforts are made to purify or separate it

so extracting yellowcake is "verboten"
by John Futter
Mon Oct 12, 2020 6:17 pm
Forum: Vacuum Technology (& FAQs)
Topic: LCD Vacuum Sensor
Replies: 14
Views: 3609

Re: LCD Vacuum Sensor

Most of the thermocouple gauges use the octal valve (tube) plug on them so you will want the octal valve (tube) socket