I was wanting to review the background peaks caused by my Am241 exciter and Pb shield.? In the process I moved the detector from a painted window sill (blue) to a bare particle board (green).? To my surprise the Ti peak that Dud noted recently went away completely.? I am guessing that the paint contains Ti.?

Hi Geo,

OK I understand, no test input to the module.? FYI

Here are (attached) two versions of simple test pulse input circuits for a PMT application
designed to produce about 130 mV at the preamp output.

The first one (#018) is for a separate attachment that came with the 480 and 419 pulsers.
It looks like a Tektronix, in line, BNC attenustor and goes between the pulse generator and
the pre amp input connector.? Note std NIM 100 ohm input impedance? (98 actualy,I think)

The second one (#022)? is the Ortec 113 PMT preamp showing the built in teat pulse input
circuit.

Both about as simple as it gets.

Best

Randall




----- Original Message -----
From: GEOelectronics@...
To: [email protected]
Sent: Thu, 12 Mar 2020 13:51:47 -0700 (PDT)
Subject: Re: [XRF] DppMCA vs Theremino

Good points Randall, good to hear from you- that can work with Theremino but DppMCA doesn't have a conventional pulse input or even a connector- the sensor is hardwired to the preamplifier and it to the processor.

If things work out, later I was hoping to modify the Dpp? processor into a stand alone MCA with a connector. Problem#1? stands, an external preamplifier must still be used, and #2- they don't provide schematics.

Geo
----- Original Message -----
From: Randall Buck <rbuck@...>
To: [email protected]
Cc: [email protected]
Sent: Thu, 12 Mar 2020 14:20:09 -0400 (EDT)
Subject: Re: [XRF] DppMCA vs Theremino


I have mentioned this previously but it seems appropriate to do so again now:

A precision pulser such? as an Ortec 419 allows the user to dial up a test pulse
of Any equivalent energy, once it has been calibrated to ONE known real energy peak.

It can do this because the output voltage pulse height is based on a stable reference (0.005%/C) and
is settable via a very linear (0.1%), 10 turn, wire wound potentiometer.

Randall


----- Original Message -----
From: GEOelectronics@...
To: [email protected]
Sent: Wed, 11 Mar 2020 11:33:49 -0700 (PDT)
Subject: Re: [XRF] DppMCA vs Theremino

As long as the calibration is linear, any escape peak from Silicon will be 1.75 keV below a MAJOR peak. The height of that escape peak will be very small compared to the major peak that caused it. Look at th scan from this perspective: picture