Needing more than a spark test?

[graham-xrf]

You do exactly what I do for monitoring high voltages. I made a divider chain for displaying the kV from a adjustable 4kV 200mA power supply for a Varian transmitter tube, but at the low end, I included metering shunt extras as safety circuits in case the bottom end inadvertently went open. Also, after getting into a job using Cockroft-Walton multi-stage multipliers, I salvaged the project leftover high voltage capacitors from 20pF to about 500pF, before they were collected up for disposal in a "tidy-up". Honestly, they have not moved in years, and might be called clutter, but occasionally see use, like now with things like scintillator PMT setups.

I know you will have had a brief mental estimation on putting caps in series, so halving the capacitance while simultaneously doubling the voltage, which still remains unhelpful if the capacitors have available have values too high. In practice, it works OK, but they need high value resistors across them to share out the voltage equally. If the resistors have high enough ohms to not waste energy getting hot, then the whole thing takes ages to discharge.

For me, when you proposed using a X-ray sensitive photodiode instead of an electron tube, it brought a smile, and I readily went for it, even though it was in the face of a completely proven high voltage alternative!

 

[homebrewed]

You do exactly what I do for monitoring high voltages. I made a divider chain for displaying the kV from a adjustable 4kV 200mA power supply for a Varian transmitter tube, but at the low end, I included metering shunt extras as safety circuits in case the bottom end inadvertently went open. Also, after getting into a job using Cockroft-Walton multi-stage multipliers, I salvaged the project leftover high voltage capacitors from 20pF to about 500pF, before they were collected up for disposal in a "tidy-up". Honestly, they have not moved in years, and might be called clutter, but occasionally see use, like now with things like scintillator PMT setups.

I know you will have had a brief mental estimation on putting caps in series, so halving the capacitance while simultaneously doubling the voltage, which still remains unhelpful if the capacitors have available have values too high. In practice, it works OK, but they need high value resistors across them to share out the voltage equally. If the resistors have high enough ohms to not waste energy getting hot, then the whole thing takes ages to discharge.

For me, when you proposed using a X-ray sensitive photodiode instead of an electron tube, it brought a smile, and I readily went for it, even though it was in the face of a completely proven high voltage alternative!

A metering shunt is a good idea! I was pretty anxious about connecting the scope up to the divider, double and triple-checking the connections. Zapping the scope's input circuitry would be a real bummer.

I avoid putting capacitors (and rectifier diodes) in series to achieve higher working voltage. The weakest device in the chain -- and there always is, relatively speaking -- can overstress the other devices. In the case of capacitors, the smallest-valued one will see a higher voltage across it, so just the normal tolerance variation is working against you.

The PIN diode approach looks like it provides some energy discrimination but so far the resolution is lacking. I'm seriously looking at cooling the diode to see if that will improve the resolution. It will take some work to get a TE cooler properly set up to take care of the combination of its power dissipation and pumped heat. I have a couple of 2 x 2 TE coolers I got ages ago for a totally different purpose so I'm a little ahead of the game.

To address condensation on the cold side, I will use desiccant packets to dry the air around the detector. It shouldn't be too difficult to seal up my enclosure, using aluminum duct tape along the seams. The idea is to come up with something that allows me to test the idea in an expedient manner.

But active cooling will greatly increase the power budget, in terms of making this a portable analysis tool.

Based on information in the Theremino docs, the work that's been done to implement a fast, low noise amplifier chain isn't going to be wasted -- their approach requires a very clean signal as well.

 

[graham-xrf]

Major computer fail situation here. Main hard drive is no more!
BUT..
Fortunately, all content, Kicad work, etc had been safely backed up.

The new drive will have the latest version Linux OS, KiCad, FreeCAD, etc. Getting the main OS installation done and running is about 15 minutes from a fresh install startup, but getting all the links, passwords, bookmarks, etc and other stuff that has to be imported will have to happen slower.

Such stuff is just how life is!

 

[WobblyHand]

Major computer fail situation here. Main hard drive is no more!
BUT..
Fortunately, all content, Kicad work, etc had been safely backed up.

The new drive will have the latest version Linux OS, KiCad, FreeCAD, etc. Getting the main OS installation done and running is about 15 minutes from a fresh install startup, but getting all the links, passwords, bookmarks, etc and other stuff that has to be imported will have to happen slower.

Such stuff is just how life is!

I know how that is. Soldiering along with a lemon PC. Seems to have an intermittent system failure that I have been unable to diagnose. System just simply decides to randomly turn off the system power. One would think such a huge fault would leave some kind of debris/breadcrumbs behind, but I have yet to find any clues. No log messages, nothing in journal files, just zippo.

Trying to decide what computer (and company) to go with. Not going to buy one from my current manufacturer - all 3 of them have some curious manufacturing faults, that have me no longer willing to give them any of my money. It wouldn't surprise me one bit to find some sort of manufacturing defect in this PC, but I don't have a fully functional and as capable replacement PC to switch to. Running off an RPI4, overclocked and booting from SSD, is only a way to get by, not a replacement PC, it's too darned slow for productive work.

 

[homebrewed]

Major computer fail situation here. Main hard drive is no more!
BUT..
Fortunately, all content, Kicad work, etc had been safely backed up.

The new drive will have the latest version Linux OS, KiCad, FreeCAD, etc. Getting the main OS installation done and running is about 15 minutes from a fresh install startup, but getting all the links, passwords, bookmarks, etc and other stuff that has to be imported will have to happen slower.

Such stuff is just how life is!

It seems to have been a season of computer discontent, so to speak. What backup system are you using?

 

[graham-xrf]

It seems to have been a season of computer discontent, so to speak. What backup system are you using?

I have a completely separate 2TB SATA drive, outside the PC, but connected on its SATA cable. LinuxMint comes with several tools, but the one I use keeps updating a backup by doing snapshot deltas. That is, it only changes files in the backup that have altered in the last 15 minutes. This is a fairly standard sync backup. Not a whole system snapshot restore/dial-back. I aim it only at the folders I choose. It being Linux, all the rest of the OS is easily and swiftly replaceable.

Aside from that, I have a long-term "archive" on yet another drive, this being a network drive. It is also 2TB, but hardly 20% full. I know that we were told that "writable" CDs would be almost data save forever unless physically mangled, but the reality was the plastic scratches, and the dyes fade. Purchased music CDs were more data permanent, but still surface fragile. When it got to DVDs and "Blue-Ray" et al, I had already decided that rotating discs were perhaps a better option. SSD drives? We shall see..

The old family photo album had the nice feature that the memories would survive centuries, and were not prone to anything that would need technology that would "become unsupported", or be unrepairable. All the information we keep has to be regularly moved/converted to some new technology or format, or even just a new "version". My experience with "the cloud" has not shown me a fail (yet), but I distrust it, and I don't like being beholding to it.

So - my solution is to archive the stuff in several places, and keep them switched off most of the time.

I was itching to get back to my XRF KiCad design, and move it along some. Unfortunately, quite beside the computer problems, I have a whole lot of necessary stuff at the abode to attend to that is temporarily stalling my attempts to get to play with the machine and electronics stuff I really like.

[ EDIT: A new system is now up and running, but not yet set up the way I like, and I still have a whole bunch of software to fetch from the repository.]

 

[graham-xrf]

I know how that is. Soldiering along with a lemon PC. Seems to have an intermittent system failure that I have been unable to diagnose. System just simply decides to randomly turn off the system power. One would think such a huge fault would leave some kind of debris/breadcrumbs behind, but I have yet to find any clues. No log messages, nothing in journal files, just zippo.

Trying to decide what computer (and company) to go with. Not going to buy one from my current manufacturer - all 3 of them have some curious manufacturing faults, that have me no longer willing to give them any of my money. It wouldn't surprise me one bit to find some sort of manufacturing defect in this PC, but I don't have a fully functional and as capable replacement PC to switch to. Running off an RPI4, overclocked and booting from SSD, is only a way to get by, not a replacement PC, it's too darned slow for productive work.

Have a good, unhurried think about what to put together. I have found that almost zero ready-to-wear PC offerings manage to impress me. My best stuff has (so far) been a GigaByte or ASUS durable motherboard. I emphasize lower power, less noise, high reliability, no overclocking needed. I basically "build my own". Yes, the 500G Samsung SSD is totally silent, (save for the slow-running PSU fan), and fast, but I won't completely trust it!

Easily the most impressive is the 8GB RPi4 with 500G SSD on it's USB3. It has been my internet server and mailer since 2018, not missed a beat, and the only times it has ever rebooted is after a power outage here.

 

[WobblyHand]

Have a good, unhurried think about what to put together. I have found that almost zero ready-to-wear PC offerings manage to impress me. My best stuff has (so far) been a GigaByte or ASUS durable motherboard. I emphasize lower power, less noise, high reliability, no overclocking needed. I basically "build my own". Yes, the 500G Samsung SSD is totally silent, (save for the slow-running PSU fan), and fast, but I won't completely trust it!

Easily the most impressive is the 8GB RPi4 with 500G SSD on it's USB3. It has been my internet server and mailer since 2018, not missed a beat, and the only times it has ever rebooted is after a power outage here.

I might just build a desktop for my office - done it before, when it made a lot of sense to roll your own. I do need a laptop though. For the last decade my laptop has been my sole computer. That's the one, I'm sort of stuck on. It's not that easy to find a decent laptop that will not get screwed up running Linux and has enough RAM and disk to satisfy my needs.

As for an RPI4-8GB, I am fortunate that I have one. It lives down in the basement shop, with the spiders and whatnot. I use it to program my ELS, and occasional lookup for stuff. The Arduino IDE has become so bloated that the poor RPI bogs down just handling the UI. Compiles take a pretty long time too, like 4-8X longer than my PC. This is on an OC RPI4 with a pwm on demand fan, boots on SSD, and runs a 64 bit OS. For the price I paid, it really is pretty good - but honestly, it is so much slower than my laptop.

 

[rabler]

Ugh, one of my "side" jobs was running a small vmware cloud on several good sized servers, with backup to Amazon S3, etc. All this stuff brings back nightmares I eventually hired a couple of sys admins. Then retired, so now I live with what I build. Currently using a couple of Asustor NAS units, one as a backup and network file server, and the other to back up the first.

The Arduino IDE has become so bloated that the poor RPI bogs down just handling the UI.

I'm thinking I need to switch back to the Arduino IDE to get the Adafruit TFT interface library running, but haven't used it since pre-2.0 This isn't very encouraging.

I've been checking rpilocator.com a few times a week for RPI 4's for several months. But all the US distributors sell out within hours. I ended up buying an el-cheapo Intel NUC to run a linux backend to a couple projects.

 

[WobblyHand]

Ugh, one of my "side" jobs was running a small vmware cloud on several good sized servers, with backup to Amazon S3, etc. All this stuff brings back nightmares I eventually hired a couple of sys admins. Then retired, so now I live with what I build. Currently using a couple of Asustor NAS units, one as a backup and network file server, and the other to back up the first.

I'm thinking I need to switch back to the Arduino IDE to get the Adafruit TFT interface library running, but haven't used it since pre-2.0 This isn't very encouraging.

I've been checking rpilocator.com a few times a week for RPI 4's for several months. But all the US distributors sell out within hours. I ended up buying an el-cheapo Intel NUC to run a linux backend to a couple projects.

On a NUC or any proper PC or Mac, Arduino IDE2 or 1 is ok.

It's just that the poor little PI just isn't make for that kind of work. It's ok to browse the web, and read email. The Pi just plain isn't equivalent to an i7 running at 2.3GHz with 16 cores, 32GB RAM, Nvidia RTX2060 with 6GB, and a 1TB NVMe, anyone who says otherwise, should be tarred and feathered. The Pi is handy for all sorts of things - even an emergency PC, but it's not a high performance engine by any stretch of the imagination. It's slow compared to any modern PC.

I signed up at Adafruit to get on their waiting list for any RPI4's >= 4GB a year ago. I have never gotten that email or notification. rpilocator just isn't working for me, at all. RPI itself has abandoned the hobbyists, at least for now, to service their commercial clients, they have publicly stated that. It will still be a while before RPI's come back. Don't know if the world will care much, because we will have all moved onto something else better by then... Still, I could use a couple of them, if I could actually get one... I'd like to replace my 3d printer controller, and my pi-hole controller with RPI4's.