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Fast pulse amplifiers for scintillation output from PMT

Dear all,

I am doing developing a fast time-resolution scintillation detector for
a high density focused microbeam (around 10^8cps), directly from the
PMT output, I've got 2ns wide voltage pulses output. The resolution
time is fast, but the pulse height is only 6mV, it is not enough to
directly trigger a Single-Channel-Analyser (usually a minimum threshold
about 30-50mV),
a fast, broadband pulse amplifier is need to make an amplification,
with the time resolution ability still kept good after it.

So, I am thinking about designing or searching such suitable amplifiers
for this purpose, anyone has experience can give me advices? Products
information or home-dsign solutions?
Maybe an fast Op-Amp can be used for this ?

Thanks
 
J

jgreimer

Jan 1, 1970
0
Do you have an estimate of the outut impedance of the PMT and the input
impedance of the Single Channel Analyzer?
 
J

John Larkin

Jan 1, 1970
0
Dear all,

I am doing developing a fast time-resolution scintillation detector for
a high density focused microbeam (around 10^8cps), directly from the
PMT output, I've got 2ns wide voltage pulses output. The resolution
time is fast, but the pulse height is only 6mV, it is not enough to
directly trigger a Single-Channel-Analyser (usually a minimum threshold
about 30-50mV),
a fast, broadband pulse amplifier is need to make an amplification,
with the time resolution ability still kept good after it.

So, I am thinking about designing or searching such suitable amplifiers
for this purpose, anyone has experience can give me advices? Products
information or home-dsign solutions?
Maybe an fast Op-Amp can be used for this ?

Thanks

A fast opamp, an AD8001 or something, should work OK. At these speeds,
and to keep up linearity, you might go for two stages, with a gain of
3 or 4 per stage.

Several people make small wideband amp boxes... names escape me at
this instant. I'm considering doing some myself, but not this week.

You could also get a voltage gain of 10 from a single MMIC, maybe a
low-noise SiGe part, like SGA-3586, but it would be AC coupled, and
invert.

John
 
I think the impedance macthing is not a problem now, the load resistor
and signal cable and the anti-reflection resistor behind the PMT are
all fixed 50ohm, the SNR is good, thus the reason why the pulse height
is not enough (only 6mV) is mainly physics factors.
So following work should be enhance the pulse height by two means:
electronic amplification and increase the photon collection effciency
of the photomultiplier, while the latter maybe difficult, so the best
solution should still be fast pulse amplification.
 
Thank you John, for the advices on the amplifier, I tried the typical
spectroscopy amplifier and a charge-sensitive preamplifier
respectively, both NIM module, but not signal displayed on the
osciliscope, maybe the frequency ability of these two are far not
enough for such an fast pulse amplification.
 
N

nyffeler

Jan 1, 1970
0
Dear all,

I am doing developing a fast time-resolution scintillation detector for
a high density focused microbeam (around 10^8cps), directly from the
PMT output, I've got 2ns wide voltage pulses output. The resolution
time is fast, but the pulse height is only 6mV, it is not enough to
directly trigger a Single-Channel-Analyser (usually a minimum threshold
about 30-50mV),
a fast, broadband pulse amplifier is need to make an amplification,
with the time resolution ability still kept good after it.

So, I am thinking about designing or searching such suitable amplifiers
for this purpose, anyone has experience can give me advices? Products
information or home-dsign solutions?
Maybe an fast Op-Amp can be used for this ?

Thanks

Becker-Hickl offers amplifier designed for this application (see
http://www.becker-hickl.com/pdf/dbhfah.pdf )

However I guess for a reasonable linearity of a poisson distributed pulse
source up to 10^8cps, as a PMT is, you will need one with a narrower puls than
2ns or a MCP.
 
J

Jasen Betts

Jan 1, 1970
0
I think the impedance macthing is not a problem now, the load resistor
and signal cable and the anti-reflection resistor behind the PMT are
all fixed 50ohm, the SNR is good, thus the reason why the pulse height
is not enough (only 6mV) is mainly physics factors.
So following work should be enhance the pulse height by two means:
electronic amplification and increase the photon collection effciency
of the photomultiplier, while the latter maybe difficult, so the best
solution should still be fast pulse amplification.

how about a trasformer?

____------>
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.--+--.
| |
\ |
/ -----
\ -----
/ |
| |
`--+--'
__|__
/////


Bye.
Jasen
 
oh, maybe it is also a method..I am not familiar with this, but how
about the time resolution?or the frequency performance ?
 
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