Method for simultaneously measuring the individual outputs of particle detectors in an array using charge division electronics
A detector arrangement for detecting at least one of rays, ions and particles includes a plurality of detectors. Each detector has a respective anode output and the detectors are arranged with the respective anode outputs being in an electrical series. The arrangement includes a plurality of resistive elements interspersed in the electrical series. The arrangement includes a first measurement point at a first end of the electrical series and a second measurement point at a second end of the electrical series. The arrangement includes electrical circuitry, electrically connected to the first and second measurement points for receiving electrical signals/pulses from the first and second measurement points, and for using the electrical signals/pulses from the first and second measurement points to determine which of the plurality of detectors made the detection utilizing a division of charge that exists between the first and second measurement points.
1. A detector arrangement for detecting at least one of rays, ions and particles, the arrangement including:
a plurality of detectors, each for detecting the at least one of rays, ions and particles, each detector having a respective anode output for outputting a charge upon detection of the at least one of rays, ions and particles at the respective detector, the plurality of detectors arranged with the respective anode outputs being in an electrical series;
a plurality of resistive elements, each resistive element having a resistance value, being interspersed in the electrical series with the anode outputs of the plurality of detectors;
a first measurement point at a first end of the electrical series and a second measurement point at a second end of the electrical series;
electrical circuitry, electrically connected to the first and second measurement points for receiving electrical signals/pulses from the first and second measurement points, and for using the electrical signals/pulses from the first and second measurement points to determine which of the plurality of detectors has detected the at least one of rays, ions and particles utilizing a division of charge that exists between the first and second measurement points; and
a switch interposed between at least first and second groups of the plurality of detectors, the switch having a closed position in which the electrical series is provided continually between the first and second measurement points, and the switch having an open position in which the electrical series is electrically isolated into two groups of detectors, with each group being electrically connected to only one of the first and second measurement points.
2. An arrangement as set forth in claim 1 , wherein, with the switch in the closed position, the electrical circuitry operates utilizing a division of charge between the first and second measurement points.
3. An arrangement as set forth in claim 2 , wherein, with the switch in the closed position, the electrical circuitry operates utilizing the resistance values of the plurality of resistive elements.
4. An arrangement as set forth in claim 3 , wherein the plurality of resistive elements includes a resistive element of the plurality of resistive elements being located between each adjacent pair of detector anode outputs within the electrical series and a resistive element of the plurality of resistive elements being located at each end of the series of detector anode outputs.
5. An arrangement as set forth in claim 4 , wherein, with the switch in the closed position, the electrical circuitry operates utilizing the following equations:
Q
A
=
∑
i
=
1
n
R
i
∑
i
=
1
N
+
1
R
i
Q
T
and
Q
B
=
∑
i
=
n
+
1
N
+
1
R
i
∑
i
=
1
N
+
1
R
i
Q
T
in which:
Q A is a charge at the first measurement point;
Q B is a charge at the second measurement point;
N is a total number of detectors connected within the electrical series;
i is a counting integer;
R i is the respective resistance of the respective resistive element at sequential location i; and
n is the number, counting sequentially from the first measurement point toward the second measurement point, of the detector at which the detection of the at least one of rays, ions and particles has occurred.
6. An arrangement as set forth in claim 2 , wherein the plurality of resistive elements each have the same resistance value, and a resistive element of the plurality of resistive elements being located between each adjacent pair of detector anode outputs within the electrical series and a resistive element of the plurality of resistive elements being located at each end of the series of detector anode outputs.
7. An arrangement as set forth in claim 6 , wherein, with the switch in the closed position, the electrical circuitry operates utilizing the following equations:
Q
A
=
n
(
N
+
1
)
Q
T
and
Q
B
=
(
N
-
n
)
(
N
+
1
)
Q
T
in which:
Q T is a charge generated at a respective anode output of a detector that has detected the at least one of rays, ions and particles;
Q A is a charge at the first measurement point;
Q B is a charge at the second measurement point;
N is a total number of detectors connected within the electrical series;
R is the resistance of each resistive element; and
n is the number, counting sequentially from the first measurement point toward the second measurement point, of the detector at which the detection of the at least one of rays, ions and particles has occurred.
8. An arrangement as set forth in claim 7 , wherein a specific detection event can be identified via the following:
z
=
(
Q
A
-
Q
B
)
(
Q
A
+
Q
B
)
with z within a range from −1 to 1, and the nth detector produces a value of z=1−2n/(N+1).
9. An arrangement as set forth in claim 2 , wherein, with the switch in the closed position, the electrical circuitry operates utilizing a comparison of the division of charge between the first and second measurement points.