FW: [XRF] 59.5keV spectrum cleanup
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Geo,
I
don¡¯t see how normalizing accounts for flux? There are 2 different count times
and 2 different activities? And a filter. The 1.6 mm Al ¡°filter¡± will drop the flux
by a factor of 0.5. The count times are different by a factor of 4.5, and there
is an unknown activity difference. If you count for the same times then the
peak count differences will be the activity ratio (with all other things equal).
Peak counts must be corrected for the source activity to compare the two. ?Putting
an Al filter in there is just an attenuator and only addresses the low energy
range below Al binding energy. Most filters are 100s of microns thick and are
tailored to a small energy range to kill the tube background and allow lower
limits of detection in that smaller energy range. 1.6 mm at 59 keV would act as
an overall attenuator
The
C0-57would be nice but ?has a bad $/half like ratio what about a Ba133 which would
get 80 keV + or a Eu 154 at 123KEv + ?
?
The
question I had was your photo showed a Peak Time of ¡°rise? value¡± I wonder how that
got in there.
K¡¯s
are stronger if you can get 'em and they have less interference, but the
heavies are tough? to get
Dud
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From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Monday, October 26, 2020 12:45 PM
To: [email protected]
Subject: Re: [XRF] 59.5keV spectrum cleanup
?
-----
Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Mon, 26 Oct 2020 13:27:01 -0400 (EDT)
Subject: Re: [XRF] 59.5keV spectrum cleanup
What
thickness Al filter are you using?
1.6mm
Why normalize to the Am
peak? Just use the same count time to see what the attenuation factor is for
the same source.
So the next?
experiments can use the same flux @ 59.5keV as previous experiments, to
evaluate the positive or negative aspects that the Np X-Rays and other low end
"noise" from the exciter may have . A "monochromic" test at
the expense of run time. This in prep for possible investment in Co-57 source
for K line from heavy elements. At this time?the yield of K vs L lines in
literature doesn't make that seem like a worthy investment.
What
is the Peak Time ¡°rise value¡±?
Is there another name or
description of that parameter?
RESC=?; Reset Configuration
CLCK=80;
20MHz/80MHz
TPEA=19.200;
Peaking Time
GAIF=1.0238;
Fine Gain
GAIN=18.686;
Total Gain (Analog * Fine)
RESL=204;
Detector Reset Lockout
TFLA=0.600;
Flat Top
TPFA=400; Fast
Channel Peaking Time
PURE=OFF; PUR
Interval On/Off
RTDE=OFF; RTD
On/Off
MCAS=NORM; MCA
Source
MCAC=2048;
MCA/MCS Channels
SOFF=OFF; Set
Spectrum Offset
AINP=NEG;
Analog Input Pos/Neg
INOF=DEF; Input
Offset
GAIA=14; Analog
Gain Index
CUSP=0;
Non-Trapezoidal Shaping
PURS=??;
Secondary PUR
PDMD=NORM; Peak
Detect Mode (Min/Max)
THSL=0.878;
Slow Threshold
TLLD=OFF; LLD
Threshold
THFA=53.12;
Fast Threshold
DACO=SHAPED;
DAC Output
DACF=50; DAC
Offset
RTDS=0; RTD
Sensitivity
RTDT=0.00; RTD
Threshold
BLRM=1; BLR Mode
BLRD=3; BLR
Down Correction
BLRU=0; BLR Up
Correction
GATE=OFF; Gate
Control
AUO1=SCA8;
AUX_OUT Selection
PRET=2370.0;
Preset Time
PRER=OFF;
Preset Real Time
PREC=OFF;
Preset Counts
PRCL=1; Preset
Counts Low Threshold
PRCH=8191;
Preset Counts High Threshold
HVSE=190; HV Set
TECS=230; TEC
Set
PAPS=ON; Preamp
8.5/5 (N/A)
SCOE=FA; Scope
Trigger Edge
SCOT=12; Scope
Trigger Position
SCOG=1; Digital
Scope Gain
MCSL=1; MCS Low
Threshold
MCSH=8191; MCS
High Threshold
MCST=0.01; MCS
Timebase
AUO2=ICR;
AUX_OUT2 Selection
TPMO=OFF; Test
Pulser On/Off
GPED=RI; G.P.
Counter Edge
GPIN=AUX1; G.P.
Counter Input
GPME=ON; G.P.
Counter Uses MCA_EN?
GPGA=ON; G.P.
Counter Uses GATE?
GPMC=ON; G.P.
Counter Cleared With MCA Counters?
MCAE=OFF;
MCA/MCS Enable
BOOT=ON; Turn
Supplies On/Off At Power Up
Good
luck with the total reflection it¡¯s a complicated set up.
Dud
?
?
Obviously the Pyro is much
cleaner. Mostly due to the added filters and other manufacturing differences
between
vintage low volume commercial productions vs. today's mass produced but more
safety minded production. These are thin, flat metal strips that could be taped
into position. CAVEAT- RISK FACTOR-These have been know to leak/shed. Please
don't use without a permanent Kapton or Mylar tape protective layer.
To reduce the low end energy even further, some aluminum filters were placed
between the pyro source and the sensor. Time for the scan is adjusted so the
59.5 peak is the same for both?
?
The pictures I think are striking. This will be the exciter source used for the
next series of experiments into what is called "Grazing Angle Total
Reflection XRF"" or "Edge XRF". In this method the sample
being tested for elemental content is placed edge-wise (90 degrees) to the
sensor vs. face to face, and the exciter is at right angles to the sample, thus
the "grazing angle" of excitation and the readout is gathered from
the edge of the target.
There are a number of studies being done on TR-XRF, but the search term
most?
fertile will include the term "grazing angle".
Filters remove most of the low energy component, leaving the 59.5 the same
(time adjusted)
Here is the comparison of what we have been using and the difference that can
be achieved:
The included Gamma Spectrum mode .mca files were all done with the newly
adopted 19.2us peaking time.
Some things achieved by that study thanks to suggestions of members:
Deadtime virtually eliminated.
Low end "electronic noise" virtually eliminated.
Resolution improved.
Speed of which the pattern forms improved.
Overall "look" of the scan improved.
Geo
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