SiPM Amplifier - Revision history

Senderovich: /* Limitations of the Model */

2009-02-27T21:33:14Z

Limitations of the Model

Senderovich at 21:29, 27 February 2009

2009-02-27T21:29:27Z

Senderovich at 21:23, 29 December 2008

2008-12-29T21:23:11Z

Senderovich at 21:16, 29 December 2008

2008-12-29T21:16:51Z

Senderovich: /* The circuit diagram */

2008-03-04T02:51:34Z

The circuit diagram

Senderovich: /* The circuit diagram */

2008-03-04T02:51:04Z

The circuit diagram

Senderovich: /* The circuit diagram */

2008-03-04T02:50:50Z

The circuit diagram

Senderovich: /* The circuit diagram */

2008-03-04T02:50:17Z

The circuit diagram

Senderovich: /* The circuit diagram */

2008-03-04T02:49:54Z

The circuit diagram

Krueger at 14:44, 10 July 2007

2007-07-10T14:44:59Z

← Older revision		Revision as of 21:33, 27 February 2009
Line 82:		Line 82:
	== Limitations of the Model ==		== Limitations of the Model ==

−	On of the principal limitations of this model turned out to be its inability to predict high-frequency behavior. Though the bandwidth inherent in the transistors themselves (4-5 GHz) was not explicitly in the model, the low-pass behavior due to source capacitance and amplifier input impedance should appear in the solutions naturally. It turned out that the more accurate modeling of the SiPM discharge as parallel injection of I<sub>in</sub> ''in parallel'' with the intrinsic SiPM capacitor recovers this behavior. Including this capacitance (labeled ''CS'') and a parallel current injection loop restored the sensitivity to input impedance. This input impedance turned out to be a challenge for achieving faster signals desired in the tagger microscope electronics. This issue is further discussed in a dedicated page:[[SiPM Amplifier Optimization]]	+	One of the principal limitations of this model turned out to be its inability to predict high-frequency behavior. Though the bandwidth inherent in the transistors themselves (4-5 GHz) was not explicitly in the model, the low-pass behavior due to source capacitance and amplifier input impedance should appear in the solutions naturally. It turned out that the more accurate modeling of the SiPM discharge as parallel injection of I<sub>in</sub> ''in parallel'' with the intrinsic SiPM capacitor recovers this behavior. Including this capacitance (labeled ''CS'') and a parallel current injection loop restored the sensitivity to input impedance. This input impedance turned out to be a challenge for achieving faster signals desired in the tagger microscope electronics. This issue is further discussed in a dedicated page:[[SiPM Amplifier Optimization]]

← Older revision		Revision as of 21:29, 27 February 2009
Line 78:		Line 78:

	Varying the input current from 0 to 2A results in a clean straight line that intersects the origin. Thus we can say that the amplifier has a transimpedance gain (programmable based on input parameters; in particular V<sub>c</sub>) and no DC bias.		Varying the input current from 0 to 2A results in a clean straight line that intersects the origin. Thus we can say that the amplifier has a transimpedance gain (programmable based on input parameters; in particular V<sub>c</sub>) and no DC bias.
		+
		+
		+	== Limitations of the Model ==
		+
		+	On of the principal limitations of this model turned out to be its inability to predict high-frequency behavior. Though the bandwidth inherent in the transistors themselves (4-5 GHz) was not explicitly in the model, the low-pass behavior due to source capacitance and amplifier input impedance should appear in the solutions naturally. It turned out that the more accurate modeling of the SiPM discharge as parallel injection of I<sub>in</sub> ''in parallel'' with the intrinsic SiPM capacitor recovers this behavior. Including this capacitance (labeled ''CS'') and a parallel current injection loop restored the sensitivity to input impedance. This input impedance turned out to be a challenge for achieving faster signals desired in the tagger microscope electronics. This issue is further discussed in a dedicated page:[[SiPM Amplifier Optimization]]

@@ Line 3: / Line 3: @@
 == The circuit diagram ==
-[[Image:SSPM Amplifier Circuit Diagram.jpg|thumb|500px|Circuit diagram]]
+The amplifier circuit diagram shown below was developed through combining the diagram supplied by Photonique (lacking component values, and having several extra components) and the physical circuit (having most components labeled).
 The component values are shown below.  The capacitors are unlabeled on any diagram, so values are not known for those components.
@@ Line 11: / Line 9: @@
 For information regarding the node voltages and branch currents, see the article on the [[MATLAB amplifier in detail]].
-{| align="center" border="1" cellpadding="8" cellspacing="0" style="text-align:center; font-family:times"
 |+ '''Component values'''
 |-
@@ Line 38: / Line 40: @@
 | VT<sub>2</sub> || W1S <small>(13)</small> || Philips BFT 92
 |}
 == MATLAB model ==

← Older revision		Revision as of 21:16, 29 December 2008
Line 1:		Line 1:
−	The silicon photomultipliers (SiPM) we are using in our experiment were purchased from [http://www.photonique.ch/ Photonique]. Photonique also supplies analog electronics boards to amplify the signals from the SiPMs. This page discusses the analysis and modeling of the amplifier circuit.	+	The silicon photomultipliers (SiPM) we are using in our experiment were purchased from [http://www.photonique.ch/ Photonique]. Photonique also supplies analog electronics boards to amplify the signals from the SiPMs. This page discusses the analysis and modeling of the amplifier circuit as well as design of the amplifier suitable for the readout of the tagger microscope.

	== The circuit diagram ==		== The circuit diagram ==

@@ Line 3: / Line 3: @@
 == The circuit diagram ==
-[[Image:SSPM Amplifier Circuit Diagram.jpg|thumb|400px|Circuit diagram]]
+[[Image:SSPM Amplifier Circuit Diagram.jpg|thumb|500px|Circuit diagram]]
 The amplifier circuit diagram shown to the right was developed through combining the diagram supplied by Photonique (lacking component values, and having several extra components) and the physical circuit (having most components labeled).

@@ Line 34: / Line 34: @@
 ! colspan="3" style="background:#ffdead; text-align:left" | Transistors
 |-
-| <math>VT_1</math> || E2P <small>(1717)</small> || Philips BFS 17A
+| VT<sub>1</sub> || E2P <small>(1717)</small> || Philips BFS 17A
 |-
-| <math>VT_2</math> || W1S <small>(13)</small> || Philips BFT 92
+| VT<sub>2</sub> || W1S <small>(13)</small> || Philips BFT 92
 |}
@@ Line 43: / Line 43: @@
 :''Main article: [[MATLAB amplifier in detail]]''
-We developed a model for this circuit in MATLAB to simulate its behavior and study various parameters, especially gain as a function of power voltage.  The Photonique documentation claims that the power voltage can be varied between four and nine volts in order to tune the gain of the amplifier.  The MATLAB model is a linearized system of twenty-four equations, with the voltages and currents on the circuit being the twenty-four unknowns.  There are four input parameters: input current (<math>I_{in}</math>, in amps), the bias voltage (<math>V_b</math>, in volts), the power voltage (<math>V_c</math>, in volts), and the frequency (<math>f</math>, in hertz).  The resistor values are mostly the same as the ones given for the above diagram, but some were changed to fit the model to actual data.  We also add a load resistor from <math>V_{out}</math> to GND, with a value of <math>50\Omega</math>.  The transistors are described by a series of parameters from the [http://en.wikipedia.org/wiki/Gummel-Poon_Model Gummel-Poon SPICE model], and we included our best guesses of the capacitor values.
+We developed a model for this circuit in MATLAB to simulate its behavior and study various parameters, especially gain as a function of power voltage.  The Photonique documentation claims that the power voltage can be varied between four and nine volts in order to tune the gain of the amplifier.  The MATLAB model is a linearized system of twenty-four equations, with the voltages and currents on the circuit being the twenty-four unknowns.  There are four input parameters: input current (I<sub>in</sub>, in amps), the bias voltage (V<sub>b</sub>, in volts), the power voltage (V<sub>c</sub>, in volts), and the frequency (f, in hertz).  The resistor values are mostly the same as the ones given for the above diagram, but some were changed to fit the model to actual data.  We also add a load resistor from V<sub>out</sub> to GND, with a value of 50&#937;.  The transistors are described by a series of parameters from the [http://en.wikipedia.org/wiki/Gummel-Poon_Model Gummel-Poon SPICE model], and we included our best guesses of the capacitor values.
 The model itself can be found [http://zeus.phys.uconn.edu/halld/tagger/electronics/design-6-2007/SSPM_amp.zip here].
@@ Line 49: / Line 49: @@
 == Responses of the model ==
-We ran simulations of the MATLAB model while varying the input parameters to generate data on how the amplifier responds to each input.  We used as a baseline test the inputs <math>V_b = 20\mbox{V}</math>, <math>V_c = 5\mbox{V}</math>, <math>f = 100\mbox{MHz}</math>, and <math>I_{in} = 1\mbox{mA}</math>, then varied one parameter at a time to generate responses.
+We ran simulations of the MATLAB model while varying the input parameters to generate data on how the amplifier responds to each input.  We used as a baseline test the inputs V<sub>b</sub> = 20V, V<sub>c</sub> = 5V, f = 100MHz, and I<sub>in</sub> = 1mA, then varied one parameter at a time to generate responses.
 === Bias voltage ===
-We varied the bias voltage from 0 to 50V.  Within this range the output (<math>V_{out}</math>) does not vary at all.
+We varied the bias voltage from 0 to 50V.  Within this range the output (V<sub>out</sub>) does not vary at all.
 === Power voltage ===
-The amplifier's response to varying the power voltage (<math>V_c</math>) from 0 to 10V is shown in the image below.
+The amplifier's response to varying the power voltage (V<sub>c</sub>) from 0 to 10V is shown in the image below.
 [[Image:Amplifier Response to Power (2007-07-03).png]]
-Note that the vertical axis can be read as either the output voltage (<math>V_{out}</math>) in mV or as the transimpedance gain in <math>\Omega</math>.
+Note that the vertical axis can be read as either the output voltage (V<sub>out</sub>) in mV or as the transimpedance gain in &#937;.
 === Frequency ===
-The amplifier's response to varying the frequency (<math>f</math>) is shown in the image below.
+The amplifier's response to varying the frequency (f) is shown in the image below.
 [[Image:Amplifier Response to Frequency (2007-07-03).png]]
-Note that the vertical axis can be read as either the output voltage (<math>V_{out}</math>) in mV or as the transimpedance gain in <math>\Omega</math>.
+Note that the vertical axis can be read as either the output voltage (V<sub>out</sub>) in mV or as the transimpedance gain in &#937;.
 === Input current ===
-Varying the input current from 0 to 2A results in a clean straight line that intersects the origin.  Thus we can say that the amplifier has a transimpedance gain (programmable based on input parameters; in particular <math>V_c</math>) and no DC bias.
+Varying the input current from 0 to 2A results in a clean straight line that intersects the origin.  Thus we can say that the amplifier has a transimpedance gain (programmable based on input parameters; in particular V<sub>c</sub>) and no DC bias.