Semiconductor radiation detector

Claim 2

A semiconductor radiation detector comprising: a) a radiation detecting element made of a compound semiconductor and operable at room temperature in response to a radiation event to produce a corresponding current signal; b) means for preamplifying said current signal to roduce a corresponding voltage signal; c) means for shaping and amplifying said signal from said preamplifying means, including a quasi-gaussian filter comprising a combination of a first differentiator and an integrator ; d) means for obtaining information about charge collection time at each radiation event by comparing the pulse height of a signal caused by the output from said first differentiator and the pulse height of the output from said shaping and amplifying means; e) means for correcting the pulse height of said output signal from said shaping and amplifying means in accordance with said information about charge collection time at each radiation event, thereby to improve the deterioration of the energy resolution caused by incomplete charge collection.

Claim 3

The radiaiton detector of claim 1, wherein said shaping and amplifying means including a pseudo-trapezoidal filter having a gated integrator for integrating the signal used by the output from said quasi-gaussian filter for a predetermined period of time.

Claim 4

The radiaiton detector of claim 1, wherein said means for obtaining information about charge collection time comprises a second differentiator having a shorter time constant than that of said first differentiator and being so arranged as to receive the output from said first differentiator to produce a pulse signal, and means for comparing the pulse height of said pulse signal from said second differentiator and the pulse helght of the out put from said pulse shaping and amplifying means.

Claim 5

A semiconductor position-sensitive radiation detector, comprising: a) radiation detecting means comprising a plurality of radiaiton detecting elements each made of a compound semiconductor and having a positive and a negative electrode and operable at room temperature, said radiation detecting elements being so arranged in row and column as to form a matrix; b) digital position signal producing means comprising; b-1) a first group of preamplifiers each connected through a common line to said radiation detecting elements in each row of said matrix at one of said positive and negative electrodes so as to produce a first detection signal caused by a radiation event detected by each of said detecting elements in each row of said matrix, b-2) a first group of differentiator/amplifiers each connected to one of said first gruup of preamplifiers, b-3) a first group of discriminators each connected to one of said first group of differentiator/amplifiers to produce a first digital pulse signal, b-4) a first encoder for encoding said first digital pulse signal to produce a first digital position signal, b-5) a second group of preamplifiers each connected through a common line to said radiaiton detecting elements in each column of said matrix at the other of said positive and negative electrodes so as to produce a second detection signal caused by a radiation event detected by each of said detecting elements in each column of said matrix, b-6) a second group of d i fferentiator/amplifiers cach connected to one of said second group of preamplifiers, b-7) a second group of discr iminators earch connected to one of said second group of differentiator/amplifiers to produce a second digital pulse signal, and b-8) a second encoder for encoding said second digital pulse signal to produce a second digital position signal; c) coincidence detecting means for checking whether said first and second detection signals coincide within a predetermined period of time to produce an output signal only when coincidence is detected; d) energy signal providing means including an analog multiplexer connected through a delay circuit to each of said differentiator/ amplifiers in at least one of said first and second groups to produce an output, and an integrator/amplifier receiving said output from said multiplexer, said differentiator/amplifiers and integrator/ amplifier being combined to form d main amplifier to produce an energy signal; e) a pulse height analyzer for determining whether said energy signal is within at least one energy window; f) means including an auxiliary amplifier having a characteristic to amplify high frequency components with a higher gain than said integrator/amplifier and connected to the output of said multiplexer in parallel with said integrator/amplifier, and a circuit for comparing the height of the output from said auxiliary amplifier and that of the output from said integrator/amplifier, thereby to obtain information about the charge collection time at each radiation event detected by said detecting elements; g) means for correcting said energy signal relatively with respect to said energy window of said pulse height analyzer in accordance with said information about, charge collection time at each radiatiun event.. thereby to improve deterioration of the energy resolution which would otherwise be caused by incomplete charge collection; and h) means for adjustig the degree of correction by said correcting means at each radiation event in accordance with the contents read out from a memory addressed by said digital position signals obtained at each radiation event.

Claim 6

A semiconductor position-sensitive radiation detector, comprising: a) radiation detecting means comprising a plurality of radiaiton detecting elements each made of a compound semiconductor and having a positive and a negative electrode and operable at room temperature, said radiation detecting elements being so arranged in row and column as to form a matrix; b) digital position signal producing means comprising; b-1) a first group of preamplifiers each connected through a common line to said radiation detecting elements in each row of said matrix at one of said positive and negative electrodes so as to produce a first detection signal caused by a radiation event detected by each of said detecting elements in each row of said matrix, b-2) a first group of differentiator/amplifiers each connected to one of said first gruup of preamplifiers, b-3) a first group of discriminators each connected to one of said first group of differentiator/amplifiers to produce a first digital pulse signal, b-4) a first encoder for encoding said first digital pulse signal to produce a first digital position signal, b-5) a second group of preamplifiers each connected through a common line to said radiaiton detecting elements in each column of said matrix at the other of said positive and negative electrodes so as to produce a second detection signal caused by a radiation event detected by each of said detecting elements in each column of said matrix, b-6) a second group of d i fferentiator/amplifiers cach connected to one of said second group of preamplifiers, b-7) a second group of discr iminators earch connected to one of said second group of differentiator/amplifiers to produce a second digital pulse signal, and b-8) a second encoder for encoding said second digital pulse signal to produce a second digital position signal; c) coincidence detecting means for checking whether said first and second detection signals coincide within a predetermined period of time to produce an output signal only when coincidence is detected; d) energy signal providing means including an analog multiplexer connected through a delay circuit to each of said differentiator/ amplifiers in at least one of said first and second groups to produce an output, and an integrator/amplifier receiving said output from said multiplexer, said differentiator/amplifiers and integrator/ amplifier being combined to form d main amplifier to produce an energy signal; e) a pulse height analyzer for determining whether said energy signal is within at least one energy window; f) means including an auxiliary amplifier having a characteristic to amplify high frequency components with a higher gain than said integrator/amplifier and connected to the output of said multiplexer in parallel with said integrator/amplifier, and a circuit for comparing the height of the output from said auxiliary amplifier and that of the output from said integrator/amplifier, thereby to obtain information about the charge collection time at each radiation event detected by said detecting elements; g) means for correcting said energy signal relatively with respect to said energy window of said pulse height analyzer in accordance with said information about, charge collection time at each radiatiun event.. thereby to improve deterioration of the energy resolution which would otherwise be caused by incomplete charge collection; and h) means for adjustig the degree of correction by said correcting means at each radiation event in accordance with the contents read out from a memory addressed by said digital position signals obtained at each radiation event.

Claim 7

The position-sensitive radiaiton detector of claim 4, wherein said correcting means comprises means for changing said energy signal or amplify said energy signal with a different gain in accordance with said informaiton about charge collection time, and means for adjusting the degree of correction of said energy signal.

Claim 8

The position-sensitive radiaiton detector of claim 4, wherein said correcting means comprises means for changing the level signal which defines the energy window of said pulse height analyzer or amplifying said level signal with different gain in accordance with said information about charge collection time, and means for adjusting the degree of correction of said level signal.