-
E. Tuominen,
P. Anbinderis,
T. Anbinderis,
R. Bates,
W. de Boer,
E. Borchi,
M. Bruzzi,
C. Buttar,
W. Chen,
V. Cindro, [......],
C. Parkes,
K. Piotrzkowski,
S. Pirollo,
P. Pusa,
J. Raisanen,
E. Tuovinen,
J. Vaitkus,
E. Verbitskaya,
S. Vayrynen,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: CERN RD39 Collaboration develops radiation-hard cryogenic silicon detectors. Recently, we have demonstrated improved radiation hardness in novel Current Injected Detectors (CID). For detector characterization, we have applied cryogenic Transient Current Technique (C-TCT). In beam tests, heavily irradiated CID detector showed capability for particle detection. Our results show that the CID detectors are operational at the temperature -50degC after the fluence of 1 times 10<sup>16</sup> 1 MeV neutron equivalent/cm<sup>2</sup>.
IEEE Transactions on Nuclear Science 09/2009; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The muon spin precession frequencies in the semimetals As, Sb and Bi have been studied as function of temperature and applied magnetic field. In Sb an anomalously large, temperature dependent and anisotropic Knight shift was found (at T = 2 K, Kiso = 0.9%, Kax = 0.3%). The shift is small above 100 K. The results are qualitatively discussed in terms of two models: (i) a shallow donor state and (ii) as partly bound electron states at an impurity charge in a metal. This large Knight shift is not found in As and Bi.
Physica Scripta 01/2007; 20(1):98. · 1.20 Impact Factor
-
B. Perea Solano,
M.C. Abreu,
V. Avati,
T. Boccali,
V. Boccone,
M. Bozzo,
R. Capra,
L. Casagrande,
W. Chen,
K. Eggert, [......], T.O. Niinikoski,
F. Oljemark,
V.G. Palmieri,
P. Rato Mendes,
S. Rodrigues,
P. Siegrist,
L. Silvestris,
P. Sousa,
S. Tapprogge,
B. Trocmé
[show abstract]
[hide abstract]
ABSTRACT: We report measurements in a high-energy pion beam of the sensitivity of the edge region in “edgeless” planar silicon pad diode detectors diced through their contact implants. A large surface current on such an edge prevents the normal reverse biasing of the device, but the current can be sufficiently reduced by the use of a suitable cutting method, followed by edge treatment, and by operating the detector at low temperature. The depth of the dead layer at the diced edge is measured to be (12.5±8stat..±6syst.) μm.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2006;
-
B. Perea Solano,
M.C. Abreu,
V. Avati,
T. Boccali,
V. Boccone,
M. Bozzo,
R. Capra,
L. Casagrande,
W. Chen,
K. Eggert, [......], T.O. Niinikoski,
F. Oljemark,
V.G. Palmieri,
P. Rato Mendes,
S. Rodrigues,
P. Siegrist,
L. Silvestris,
P. Sousa,
S. Tapprogge,
B. Trocmé
[show abstract]
[hide abstract]
ABSTRACT: We report measurements in a high-energy beam of the sensitivity of the edge region in “edgeless” planar silicon pad diode detectors. The edgeless side of these rectangular diodes is formed by a cut and break through the contact implants. A large surface current on such an edge prevents the normal reverse biasing of this device above the full depletion voltage, but we have shown that the current can be sufficiently reduced by the use of a suitable cutting method, followed by edge treatment, and by operating the detector at a low temperature. A pair of these edgeless silicon diode pad sensors was exposed to the X5 high-energy pion beam at CERN, to determine the edge sensitivity. The signal of the detector pair triggered a reference telescope made of silicon microstrip detector modules. The gap width between the edgeless sensors, determined using the tracks measured by the reference telescope, was then compared with the results of precision metrology. It was concluded that the depth of the dead layer at the diced edge is compatible with zero within the statistical precision of ±8 μm and systematic error of ±6 μm.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2005;
-
[show abstract]
[hide abstract]
ABSTRACT: A technique for the investigation of deep levels on irradiated silicon by measuring the charge collection efficiency (CCE) of samples from 220 down to 90 K is presented here. The temperature and time dependencies of the CCE have been measured with unprecedented precision and resolution for standard and oxygenated silicon diodes, and the data obtained have been analyzed in the framework of the Lazarus effect and polarization models, extracting information about the radiation-induced deep levels in the materials. Results are presented and discussed in terms of these models and what can be inferred from them when applied to experimental data.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new technique for the investigation of deep levels on irradiated silicon by measuring the charge collection efficiency (CCE) of samples from 220 down to 90 K is presented here. The temperature and time dependencies of the CCE have been measured with unprecedented precision and resolution for standard and oxygenated silicon diodes, and the data obtained have been analyzed in the framework of the Lazarus effect and polarization models, extracting information about the radiation-induced deep levels in the materials. Results are presented and discussed in terms of these models and what can be inferred from them when applied to experimental data.
Ieee Transactions on Nuclear Science. 01/2004; 51(6):3069-3075.
-
J. Harkonen,
M. Abreu,
P. Anbinderis,
T. Anbinderis,
N. D'Ambrosio,
W. Boer de,
E. Borchi,
K. Borer,
M. Bruzzi,
S. Buontempo, [......],
P. Sousa,
E. Tuominen,
E. Tuovinen,
J. Vaitkus,
E. Verbitskaya,
C. Da Via,
L. Vlasenko,
M. Vlasenko,
E. Wobst,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: The CERN RD39 Collaboration is developing super-radiation hard cryogenic Si detectors for applications in experiments of the LHC and the future LHC Upgrade. Radiation hardness up to the fluence of 10(16)n(eq)/cm(2) isrequired in the future experiments. Significant improvement in the radiation hardness of silicon sensors has taken place during the past years. However, 10(16) n(eq)/cm(2) is well beyond the radiation tolerance of even the most advanced semiconductor detectors made by commonly adopted technologies. Furthermore, at this radiation load the carrier trapping will limit the charge collection depth to the range of 20-30mum regardless of the depletion depth. The key of our approach is freezing the trapping that affects Charge Collection Efficiency (CCE). (C) 2004 Elsevier B.V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2004; 535(1-2):384-388.
-
[show abstract]
[hide abstract]
ABSTRACT: A new technique for the investigation of deep levels on irradiated silicon by measuring the charge collection efficiency (CCE) of samples from 220 K down to 90 K is presented here. The temperature and time dependencies of the CCE have been measured with unprecedented precision and resolution for standard and oxygenated silicon diodes, and the data obtained have been analyzed in the framework of the Lazarus effect and polarization models, extracting information about the radiation-induced deep levels in the materials. Results are presented and discussed in terms of these models and what can be inferred from them when applied to experimental data.
Nuclear Science Symposium Conference Record, 2003 IEEE; 11/2003
-
M. Abreu,
N. D'Ambrosio,
W. Bell,
P. Berglund,
E. Borchi,
W. de Boer,
K. Borer,
M. Bruzzi,
S. Buontempo,
L. Casagrande, [......],
S. Pirollo,
P. Rato Mendes,
G. Ruggiero,
P. Sonderegger,
E. Tuominen,
E. Verbitskaya,
C. da Viá,
S. Watts,
E. Wobst,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: The CERN RD39 Collaboration studies the possibility to extend the detector lifetime in a hostile radiation environment by operating them at low temperatures. The outstanding illustration is the Lazarus effect, which showed a broad operational temperature range around 130 K for neutron irradiated silicon detectors.
Nuclear Physics B - Proceedings Supplements. 01/2003;
-
E. Verbitskaya,
M. Abreu,
P. Anbinderis,
T. Anbinderis,
N. D'Ambrosio,
W. de Boer,
E. Borchi,
K. Borer,
M. Bruzzi,
S. Buontempo, [......],
P. Rato Mendes,
G. Ruggiero,
K. Smith,
P. Sonderegger,
P. Sousa,
E. Tuominen,
J. Vaitkus,
C. da Viá,
E. Wobst,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: 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 γ-rays, 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+ and n+ 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. 01/2003;
-
[show abstract]
[hide abstract]
ABSTRACT: High-resistivity p<sup>+</sup>/n/n<sup>+</sup> Si pad detectors (0.25 cm<sup>2</sup>) were diced, using different dicing tools and methods, into a shape having on one edge no dead space ("edgeless detectors"). The dicing was extended into the sensitive area of the front p<sup>+</sup> implant. Two different dicing tools were used: laser cutting and scribing. Dicing methods included cutting from the front p+ side and from the back n<sup>+</sup> side. It was found that with no chemical or aging treatment of edges cut in this way, all the detectors (diced with different tools and methods) suffered from a very high leakage current of hundreds of μAs to mA at full depletion voltage (V<sub>fd</sub>), as compared with a few nA before dicing, when measured the same day after dicing. All such detectors showed breakdown just at or near V<sub>fd</sub> ∼ 80-100 V. However, after one day of room temperature aging in air, the leakage currents at Vfd improved dramatically to 1-2 μA if diced (laser cutting and scribing) from the back side. Also, there was no breakdown up to 500 V. There was little improvement over time if the sensor was diced from the front side. After at least one day of aging, detectors diced from the back side showed normal C-V and charge collection behavior. Nevertheless, the remaining leakage seems to be dominated by surface current. Chemical treatment, though, is promising for further reduction of the surface current below 1 μA at Vfd and below 10 μA at 500 V.
IEEE Transactions on Nuclear Science 07/2002; · 1.45 Impact Factor
-
E. Verbitskaya,
A. Abreu,
V. Bartsch,
W. Bell,
P. Berglund,
J. Bol,
W. de Boer,
K. Borer,
S. Buontempo,
L. Casagrande, [......],
V. O'Shea,
S. Pagano,
V.G. Palmieri,
S. Paul,
P. Rato Mendes,
G. Ruggiero,
L. Schmitt,
K. Smith,
P. Sousa,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: We present a study of the modeling of the electric field
distribution, which is controlled by injection and trapping of
nonequilibrium carriers, in Si detectors irradiated by high neutron
fluences. An analytical calculation of the electric field distribution
in detectors irradiated by neutrons up to fluences of 1 ·
10<sup>14</sup> to 5 · 10<sup>15</sup> cm<sup>-2</sup> shows the
possibility of reducing the full depletion voltage at low temperatures
via hole injection. For this calculation, we use the detector operating
parameters and equivalent neutron fluences expected for Large Hadron
Collider experiments. The results of the calculation are in good
qualitative agreement with published experimental data, lending strong
support for the model and for an earlier proposal of electric field
manipulation by free carrier injection
IEEE Transactions on Nuclear Science 03/2002; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: High-resistivity p(+)/n/n(+) Si pad detectors (0.25 cm(2)) were diced, using different dicing tools and methods, into a shape having on one edge no dead space ("edgeless detectors"). The dicing was extended into the sensitive area of the front p(+) implant. Two different dicing tools were used: laser cutting and scribing. Dicing methods included cutting from the front p(+) side and from the back n(+) side. It was found that, with no chemical or aging treatment of edges cut in this way, all the detectors (diced with different tools and methods) suffered from a very high leakage current of hundreds of muA's to mA at full depletion voltage (V-fd), as compared with a few nA before dicing, when measured the same day after dicing. All such detectors showed breakdown just at or near Vfd similar to 80-100 V. However, after one day of room temperature aging in air, the leakage currents at V-fd improved dramatically to 1-2 muA if diced (laser cutting and scribing) from the backside. Also there was no breakdown up to 500 V. There was little improvement over time if the sensor was diced from the front side. After at least one day of aging, detectors diced from the backside showed normal C-V and charge collection behavior. Nevertheless, the remaining leakage seems to be dominated by surface current and shows little improvement at temperatures down to 130 K. Chemical treatment, though, is promising for further reduction of the surface current < 1 muA at V-fd and < 10 muA at 500 V.
2001 Ieee Nuclear Science Symposium, Conference Records, Vols 1-4. 01/2002;
-
L. Casagrande,
M. C. Abreu,
W. H. Bell,
P. Berglund,
W. Boer de,
E. Borchi,
K. Borer,
M. Bruzzi,
S. Buontempo,
S. Chapuy, [......],
S. Pirollo,
K. Pretzl,
P. Rato,
G. Ruggiero,
K. Smith,
P. Sonderegger,
P. Sousa,
E. Verbitskaya,
S. Watts,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, "resuscitate" when operated at temperatures below 130 K. This is often referred to as the "Lazarus effect". The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors. (C) 2002 Elsevier Science B.V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2002; 477(1-3):299-303.
-
T. O. Niinikoski,
M. Abreu,
W. Bell,
P. Berglund,
W. Boer de,
E. Borchi,
K. Borer,
M. Bruzzi,
S. Buontempo,
L. Casagrande, [......],
S. Pirollo,
K. Pretzl,
P. R. Mendes,
G. Ruggiero,
K. Smith,
P. Sonderegger,
P. Sousa,
E. Verbitskaya,
S. Watts,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: We shall review test results which show that silicon detectors can withstand at 130 K temperature a fluence of 2 x 10(15)cm(-2) of 1 MeV 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 irradiated at room temperature using reactor neutrons, and in situ at low temperatures using high-energy protons and lead ions. No substantial difference was observed between samples irradiated at low temperature and those irradiated at room temperature. after beneficial annealing. The design of low-mass modules for low-temperature trackers is discussed briefly, together with the cooling circuits for small and large systems. (C) 2002 Elsevier Science B.V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2002; 476(3):569-582.
-
[show abstract]
[hide abstract]
ABSTRACT: High-resistivity p(+)/n/n(+) Si pad detectors (0.25 cm(2)) were diced, using different dicing tools and methods, into a shape having on one edge no dead space ("edgeless detectors"). The dicing was extended into the sensitive area of the front p(+) implant. Two different dicing tools were used: laser cutting and scribing. Dicing methods included cutting from the front p(+) side and from the back n(+) side. It was found that with no chemical or aging treatment of edges cut in this way, all the detectors (diced with different tools and methods) suffered from a very high leakage current of hundreds of muAs to mA at full depletion voltage (V-fd), as compared with a few nA before dicing, when measured the same day after dicing. All such detectors showed breakdown just at or near V-fd similar to 80-100 V However, after one day of room temperature aging in air, the leakage currents at V-fd improved dramatically to 1-2 muA if diced (laser cutting and scribing) from the back side. Also, there was no breakdown up to 500 V There was little improvement over time if the sensor was diced from the front side. After at least one day of aging, detectors diced from the back side showed normal C-V and charge collection behavior. Nevertheless, the remaining leakage seems to be dominated by surface current. Chemical treatment, though, is promising for further reduction of the surface current below 1 muA at V-fd and below 10 muA at 500 V.
Ieee Transactions on Nuclear Science. 01/2002; 49(3):1040-1046.
-
G. Ruggiero,
M. Abreu,
W. Bell,
P. Berglund,
W. Boer de,
K. Borer,
S. Buontempo,
L. Casagrande,
S. Chapuy,
V. Cindro, [......],
V. G. Palmieri,
S. Paul,
K. Pretzl,
P. R. Mendes,
K. Smith,
P. Sonderegger,
P. Sousa,
E. Verbitskaya,
S. Watts,
M. Zavrtanik
[show abstract]
[hide abstract]
ABSTRACT: 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 x 10(15) p cm(-2) 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. (C) 2002 Elsevier Science B.V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2002; 476(3):583-587.
-
[show abstract]
[hide abstract]
ABSTRACT: High-resistivity p<sup>+</sup>/n/n<sup>+</sup> Si pad detectors (0.25 cm<sup>2</sup>) were diced, using different dicing tools and methods, into a shape having on one edge no dead space ("edgeless detectors"). The dicing was extended into the sensitive area of the front p<sup>+</sup> implant. Two different dicing tools were used: laser cutting and scribing. Dicing methods included cutting from the front p<sup>+</sup> side and from the back n<sup>+</sup> side. It was found that, with no chemical or aging treatment of edges cut in this way, all the detectors (diced with different tools and methods) suffered from a very high leakage current of hundreds of μA's to mA at full depletion voltage (V<sub>fd</sub>), as compared with a few nA before dicing, when measured the same day after dicing. All such detectors showed breakdown just at or near V<sub>fd</sub>∼80-100 V. However, after one day of room temperature aging in air, the leakage currents at V<sub>fd</sub> improved dramatically to 1-2 μA if diced (laser cutting and scribing) from the backside. Also there was no breakdown up to 500 V. There was little improvement over time if the sensor was diced from the front side. After at least one day of aging, detectors diced from the backside showed normal C-V and charge collection behavior. Nevertheless, the remaining leakage seems to be dominated by surface current and shows little improvement at temperatures down to 130 K. Chemical treatment, though, is promising for further reduction of the surface current <1μA at V<sub>fd</sub> and <10 μA at 500 V.
Nuclear Science Symposium Conference Record, 2001 IEEE; 12/2001
-
V. Granata,
C. Via da,
S. Watts,
K. Borer,
S. Janos,
K. Pretzl,
B. Dezillie,
Z. Li,
L. Casagrande,
P. Collins, [......],
M. Mikuz,
M. Zavrtanik,
A. Esposito,
I. Konorov,
S. Paul,
S. Buontempo,
N. D'Ambrosio,
S. Pagano,
V. Eremin,
E. Verbitskaya
[show abstract]
[hide abstract]
ABSTRACT: A low-mass cryogenic cooling technique for silicon sensor modules has been developed in the framework of the RD39 Collaboration at CERN. A prototype low-mass beam tracker cryostat has been designed, constructed and tested for applications in fixed target experiments. We shall report here briefly the main features and results of the system. (C) 2001 Elsevier Science B,V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2001; 461(1-3):197-199.
-
L. Casagrande,
M. C. Abreu,
W. H. Bell,
P. Berglund,
W. Boer de,
K. Borer,
S. Buontempo,
S. Chapuy,
V. Cindro,
N. D'Ambrosio, [......],
K. Pretzl,
P. Rato,
G. Ruggiero,
K. Smith,
P. Sonderegger,
P. Sousa,
E. Verbitskaya,
S. Watts,
M. Zavrtanik,
R. D. Collaboration
[show abstract]
[hide abstract]
ABSTRACT: In this paper, we report on the performance of heavily irradiated silicon detectors operated at cryogenic temperatures. The results discussed here show that cryogenic operation indeed represents a reliable method to increase the radiation tolerance of standard silicon detectors by more than one order of magnitude. In particular, a 400 mum thick "double-p" silicon detector irradiated up to 1 x 10(15) n/cm(2) delivers a mip signal of about 27 000 electrons when operated at 130 K and 500 V bias. The position resolution of an irradiated microstrip detector, and "in situ" irradiation of a pad detector during operation in the cold are also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2001; 461(1-3):150-154.
