Amptek Digital Pulse Processor

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Dan Knapp
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Amptek Digital Pulse Processor

Post by Dan Knapp »

There is a good deal available on eBay on current generation Amptek digital pulse processor boards. These are the Amptek DP5/PC5 board combination (see Amptek.com). The DP5 includes an analog prefilter, an ADC, a digital pulse processor and a multichannel analyzer. It is designed to accept a radiation detector signal from a charge sensitive preamplifier. The PC5 provides power for a detector. Amptek sells these boards to OEM’s for radiation spectrum analysis in various configurations for different detectors. They also sell these in a box with connectors for lab use for $6300. These particular units were made for silicon PIN detectors, but they could be used for other detectors with the proper detector power supply (the DP5 power supply can be reconfigured, but Amptek says doing so is not a user procedure). The seller apparently got several dozen of these from a company that made X-ray fluorescence equipment. They have separate listings for new units at $500 and used units at $300, but these may well all be from the same lot since the quantity available on the used listing was recently updated. The update of the “used” listing also added quantity pricing, which suggests what the seller will take for one on a “make an offer” sale. The software for these is downloadable from Amptek along with extensive documentation in the form of manuals and application notes. These are a real bargain for the multichannel analyzer alone. I bought one with the intention of trying to use it for neutron detection with a plastic scintillator following the lead of the recently published paper from Shumlak’s lab where they digitized the data and did pulse processing with a separate computer program (viewtopic.php?f=13&t=12981&p=84373#p84373). In anticipation that others might buy and apply these, let this be the beginning of a thread for sharing application information.
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Re: Amptek Digital Pulse Processor

Post by Andrew Seltzman »

Nice find, I'll have to buy some :)
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Re: Amptek Digital Pulse Processor

Post by Andrew Seltzman »

I bought 2 of the used ones, the seller did not respond to a $250ea offer.
From the Amptek site, it appears the power supply for the pin diode is on the PC5 board which is independent from the DP5 and can be removed entirely (or probably just disconnected).
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Jim Kovalchick
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Re: Amptek Digital Pulse Processor

Post by Jim Kovalchick »

1 for 285. It looked like that amount was auto accepted because it was instant.

I downloaded all the software including developer kit.
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Re: Amptek Digital Pulse Processor

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Re: Amptek Digital Pulse Processor

Post by Chris Mullins »

I got one for $280, which was also automatically accepted.
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Jim Kovalchick
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Re: Amptek Digital Pulse Processor

Post by Jim Kovalchick »

Here is a DP5 users manual provided by Geo on a gamma spec users group.
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Re: Amptek Digital Pulse Processor

Post by Andrew Seltzman »

Got 3x pulse processors and 1x of the Si-PIN diode. it pretty much works out of the box, make sure you install the winusb drivers or it won't connect via usb. I got a good XRF spectrum of stainless steel with this unit. I was using one of these photoionizer units as an x-ray source (9.5kev peak):
https://www.ebay.com/itm/HAMAMATSU-Adva ... 1438.l2649

Of the 3 pulse processors I got 2x would not power up when connected to usb, likely a bad power converter on the board, the third board powered up fine over usb. The other 2 could still be powered up but required connection to the 5v external power pads on the PC5 board.
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Dan Knapp
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Re: Amptek Digital Pulse Processor

Post by Dan Knapp »

There were some posts to this thread lost. It would be nice if those posting have saved copies they could repost.
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Jim Kovalchick
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Re: Amptek Digital Pulse Processor

Post by Jim Kovalchick »

Dan,
I think some of the missing posts were in regard to powering up the boards with usb.

To power the boards with usb you have to jumper over the usb resistor on the board. Also there is a need for caution because the usb from a connected computer will not be able to supply connected accessories like the PC5 board.
There are alternatives to using the usb to communicate with a pc such as the ethernet port. This would allow connecting the usb to a charger.

Jim K
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Re: Amptek Digital Pulse Processor

Post by Dan Knapp »

With the holiday past, I've been able to turn my attention back to my DP5/PC5. Unfortunately, I did not print the responses that were lost on this thread, which addressed issues of powering the boards. Mine will not power up from the USB connection, either with or without the PC5 attached. My intent is to use the DP5 with a photomultiplier output. The PC5 board is marked "Si-PIN Only," so I'm guessing that these are configured only for low voltage output and will not supply the full 1500 volts. So I'll likely be using the DP5 alone with an external power supply for the photomultiplier. Andrew indicated he had supplied power via the 5V external power pads on the PC5 board (I'm assuming the pads marked "GND" and "PWR EXT" next to the eight pin header). Has anyone tried powering just the DP5 from external power? It uses a rather uncommon (to me at least) Hirose MQ172-3PA(55) connector. Does anyone know where to find one of these? Digi-Key lists it as obsolete, but even if they weren't, it's probably an item where you'd have to buy a large quantity. Would those who posted lost responses be willing to repost?
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Re: Amptek Digital Pulse Processor

Post by Andrew Seltzman »

Yes, supplying +5vdc to the pwr_ext pad on the PC 5 will power up the DP5 as well.
I believe you can solder across a resistor to allow usb power, though I think the previously posted manual is for an older version of the board.

From p22 on the manual (again I believe this manual might be for an older version of the board):
Some key points of the overall architecture are as follows:
□ The input power is nominally +5 VDC (4 V to 5.5 V acceptable). Power is usually drawn from the J9 connector. However, the DP5 may be powered from the USB bus or can be powered via the J5 interconnect. Alternately, the interconnect may be used to supply power to a daughter board.
□ To power the DP5 from the USB bus, replace R118 by a zero ohm jumper. Note that this ties the USB bus to the J9 power input and the J5 interconnects. Only power the DP5 from one source at a time. If one attempts to power simultaneously from the USB bus and from an external supply, the two regulators will be “fighting” each other, which is not good.
□ Reverse polarity protection is provided by F1 and D9. There is no over or under voltage protection.
□ F1 is a polyfuse, i.e. a resettable fuse. It goes to a high impedance with very high current but returns to low impedance after power is removed. It does not need replacing after use.
□ When the 5VDC is plugged in, the 3.3V supply in the DP5 turns on and the digital circuitry is powered. When the DP5 is configured, it then turns on its low voltage supplies (+/-5V, 2.5V, 1.2V) and the DP5 is powered. The DP5 can be configured for this to happen automatically when power is applied.
□ When the PC5 is used with the DP5, power is supplied to the PC5 via the J5 interconnect. The DP5 uses the PS Enable line to turn on the supplies in the PC5, after checking the HV polarity.
Nominal switching frequencies are >1 MHz.
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Peter Schmelcher
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Re: Amptek Digital Pulse Processor

Post by Peter Schmelcher »

The attached file is for a different rev of the board
PC5 Power Supply User’s Manual Rev. A0

The HV feedback circuit uses a resistor divider which could be changed for a different bias voltage range.
One would need to know the HV capacitor ratings or that all model variations use the same HV capacitors.
I think the Si detector max bias voltage is +200V
BTW the Si Pin Only lid is not soldered to the board it pulls off. The lid covers a 1MHz 5V switcher with an output range from 1.1 to Vin, nothing special.

-Peter
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Jim Kovalchick
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Re: Amptek Digital Pulse Processor

Post by Jim Kovalchick »

I had some time this evening to tinker with my DP5 board. I put a dab of solder between the pads at R28. I connected it by usb to my Windows 10 laptop which auto detected and loaded the correct drivers. I installed the DppMCA software which connected to the DP5 without issue. When I get more time, I will connect a preamp signal and see if board does its thing.

Jim K
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