Radiation hard position-sensitive cryogenic silicon detectors: the Lazarus effect (original) (raw)
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Charge collection efficiency of irradiated silicon detector operated at cryogenic temperatures
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
The charge collection e$ciency (CCE) of heavily irradiated silicon diode detectors was investigated at temperatures between 77 and 200 K. The CCE was found to depend on the radiation dose, bias voltage value and history, temperature, and bias current generated by light. The detector irradiated to the highest #uence 2;10 n/cm yields a MIP signal of at least 15000 e\ both at 250 V forward bias voltage, and at 250 V reverse bias voltage in the presence of a light-generated current. The`Lazarus e!ecta was thus shown to extend to #uences at least ten times higher than was previously studied.
Silicon detectors irradiated “in situ” at cryogenic temperatures
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002
Though several studies have proved the radiation tolerance of silicon detectors at cryogenic temperatures, following room temperature irradiation, no previous investigation has studied the behaviour of detectors irradiated ''in situ'' at low temperatures. In this work, effects of irradiation of 450 GeV protons at 83 K will be presented, showing that after a dose of 1.2 Â 10 15 p cm À2 a charge collection efficiency (CCE) of 55% is reached at 200 V before the annealing. The same results were found at the end of the irradiation, after the sample has spent more then one year at room temperature. This shows that the CCE recovery by low temperature operation is not affected by the temperature of irradiation and by the reverse annealing.
Cryogenic operation of silicon detectors
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
This paper reports on measurements at cryogenic temperatures of a silicon microstrip detector irradiated with 24 GeV protons to a #uence of 3.5;10 p/cm and of a p}n junction diode detector irradiated to a similar #uence. At temperatures below 130 K a recovery of charge collection e$ciency and resolution is observed. Under reverse bias conditions this recovery degrades in time towards some saturated value. The recovery is interpreted qualitatively as 0168-9002/00/$ -see front matter
Nuclear Physics B - Proceedings Supplements, 1998
Measurements performed on high resistivity silicon detectors irradiated with proton and neutron fluences, up to 3.5x1014 p/cm z and 4.0x1015 n/cm 2 respectively, are presented. The current-voltage (IV) and capacitancevoltage (CV) characteristics, as well as the charge collection efficiency (CCE) of the devices have been measured to carry out a complete detector performance analysis after irradiation, The IV, CV and CCE analyses show that the irradiated devices depart from the ideal p+n junction modelisation when the fluence (f) is of the order of 1014 + 1015 cm-2. In this fluence range, it is impossible to fully deplete the irradiated device; the CV characteristics show evidence of full depletion voltages up to 103-104 Volts; the IV and CCE(V) curves are found to be linear in this fluence range; reverse currents up to a few mA are measured. A well visible, although low, charge collection signal has been observed at 7°C after exposure to the extreme irradiation fluence of 4.0x10 Is n/cm 2. This is probably due to a very narrow active region inside the semiconductor bulk, and corresponding approximately, to a 75% inefficiency in the detector performance.
Charge collection efficiency of an irradiated cryogenic double-p silicon detector
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001
We present results on the measurement of the charge collection efficiency of a p + /n/p + silicon detector irradiated to 1u10 15 n/cm 2 , operated in the temperature range between 80 K and 200 K. For comparison, measurements obtained with a standard silicon diode (p + /n/n + ), irradiated to the same fluence, are also presented. Both detectors show a dramatic increase of the CCE when operated at temperatures around 130 K. The double-p detector shows a higher CCE regardless of the applied bias and temperature, besides being symmetric with respect to the polarity of the bias voltage. At 130 K and 500 V applied bias the double-p detector shows a CCE of 80%, an unprecedented result for a silicon detector irradiated to such a high dose.
Radiation hardness of cryogenic silicon detectors
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2002
We shall review test results which show that silicon detectors can withstand at 130K temperature a fluence of 2×1015cm–2 of 1MeV neutrons, which is about 10 times higher than the fluence tolerated by the best detectors operated close to room temperature. The tests were carried out on simple pad devices and on microstrip detectors of different types. The devices were
2003
The recovery of the charge collection efficiency (CCE) at low temperatures, the so-called ''Lazarus effect'', was studied in Si detectors irradiated by fast reactor neutrons, by protons of medium and high energy, by pions and by gamma-rays. The experimental results show that the Lazarus effect is observed: (a) after all types of irradiation; (b) before and after space charge sign inversion; (c) only in detectors that are biased at voltages resulting in partial depletion at room temperature. The experimental temperature dependence of the CCE for proton-irradiated detectors shows non-monotonic behaviour with a maximum at a temperature defined as the CCE recovery temperature. The model of the effect for proton-irradiated detectors agrees well with that developed earlier for detectors irradiated by neutrons. The same midgap acceptor-type and donor-type levels are responsible for the Lazarus effect in detectors irradiated by neutrons and by protons. A new, abnormal ''zigzag''-shaped temperature dependence of the CCE was observed for detectors irradiated by all particles (neutrons, protons and pions) and by an ultra-high dose of grays , when operating at low bias voltages. This effect is explained in the framework of the double-peak electric field distribution model for heavily irradiated detectors. The redistribution of the space charge region depth between the depleted regions adjacent to p þ and n þ contacts is responsible for the ''zigzag''-shaped curves. It is shown that the CCE recovery temperature increases with reverse bias in all detectors, regardless of the type of radiation.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
or 10cmand biased at 160 v. 14 `2 20 ns (typical of LHC operation) is better than 90% for 300 ttm detectors irradiated to a fluence Moreover, at these temperatures, the charge collection efficiency for an integration time of limits the diode reverse current and the bias voltage necessary to achieve full depletion. proton fluence and of annealing time. It is found that operating the detectors below +10°C efficiency of the charge, deposited by relativistic electrons, are presented as a function of the irradiation. The change of the diode reverse current, full depletion voltage and collection 10cm, and maintained at these temperatures during several months after the end of 14 `2 and -20°C with 24 GeV/c protons at a flux of ~ 5 >< 10cms, up to fluences of ~ 1.1 >< 9 `2 -1 High resistivity ion-implanted silicon pad detectors have been irradiated at +20°C, +10°C, 0°C Abstract University of Montreal,
New Operation Scenarios for Severely Irradiated Silicon Detectors
Proceedings of VERTEX 2009 (18th workshop) — PoS(VERTEX 2009)
Recent charge collection measurements after severe hadron irradiation have proved that n-side readout segmented planar silicon detectors can successfully operate up to the doses anticipated for the innermost layers of the upgraded experiments in the future super LHC (sLHC) at CERN. The charge collected by the irradiated sensors is sufficient to guarantee a signal over noise (S/N) ratio above 10 even for the pixel layers located at the smallest radial distance from the beam line (less than 4 cm away). The signal depends on the applied bias and voltages as high as 1000V could be required to satisfy the minimum signal height for the most exposed detectors. The radiation at the doses of the pixel layers in the sLHC also cause an important increase of the reverse current The high bias voltages and reverse currents cause significant power dissipation and adequate cooling needs to be applied to limit the current well below the thermal-runaway level.
1994
or 10cmand biased at 160 v. 14 `2 20 ns (typical of LHC operation) is better than 90% for 300 ttm detectors irradiated to a fluence Moreover, at these temperatures, the charge collection efficiency for an integration time of limits the diode reverse current and the bias voltage necessary to achieve full depletion. proton fluence and of annealing time. It is found that operating the detectors below +10°C efficiency of the charge, deposited by relativistic electrons, are presented as a function of the irradiation. The change of the diode reverse current, full depletion voltage and collection 10cm, and maintained at these temperatures during several months after the end of 14 `2 and -20°C with 24 GeV/c protons at a flux of ~ 5 >< 10cms, up to fluences of ~ 1.1 >< 9 `2 -1 High resistivity ion-implanted silicon pad detectors have been irradiated at +20°C, +10°C, 0°C Abstract University of Montreal,