The CMS silicon microstrip detectors: research and development Bacchetta, N.; Albergo, S.; Azzi, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/1999, Letnik:
426, Številka:
1
Journal Article
Recenzirano
A large quantity of silicon microstrip detectors is foreseen to be used as part of the CMS tracker. A specific research and development program has been carried out with the aim of defining layouts ...and technological solutions suitable for the use of silicon detectors in high radiation environment. Results presented here summarise this work on many research areas such as techniques for device manufacturing, pre- and post-irradiation electrical characterization, silicon bulk defects analysis and simulations, system performance analytical calculations and simulations and test beam analysis. As a result of this work we have chosen to use single-sided, AC-coupled, poly silicon biased, 300
μm thick, p
+ on n substrate detectors. We feel confident that these devices will match the required performances for the CMS tracker provided they can be operated at bias voltages as high as 500
V. Such high-voltage devices have been succesfully manufactured and we are now concentrating our efforts in enhancing yield and reliability.
The objective of the present study was to determine whether an increase in the intensity of therapy improves outcome for children with disseminated poor-risk neuroblastoma.
From January 1982 through ...November 1989, 181 children 1 year or older with newly diagnosed disseminated neuroblastoma were entered onto two consecutive studies of the Italian Cooperative Group for Neuroblastoma (ICGNB): 75 (study NB82) were enrolled from 1982 to 1984 and were treated with standard-dose (SD) chemotherapy, and 106 (study NB85) were enrolled from 1985 to 1989 and received high-dose (HD) chemotherapy. In both treatment protocols, induction therapy included peptichemio and cisplatin (at SD or HD, respectively) and removal of the primary tumor. In study NB82, children who achieved complete or partial tumor regression received SD consolidation therapy, and in study NB85 they received three cycles of HD chemotherapy (3cCT) or one cycle of myeloablative therapy (MAT) followed by autologous bone marrow transplantation (ABMT).
Compared with group NB82, the NB85 group had significantly fewer failures (no tumor response or disease progression) after administration of peptichemio (9% v 31%; P < .01), had more complete responses (CRs) and partial responses (PRs) both after treatment with cisplatin (60% v 43%; P = .01) and after surgery (76% v 57%; P < .01), and was more likely to have achieved complete excision of the primary tumor (70% v 46%; P < .01). Overall survival (OS) and progression-free survival (PFS) at 5 years were 11% and 9% in NB82, and 27% and 18% in NB85 (P < .01 for both); however, in NB85, relapses occurred even after 5 years of CR, so that PFS curves converge approximately 7 years after diagnosis. Median survival time was 14 months in NB82 and 24 months in NB85. Children in the NB85 group who after achievement of CR were consolidated with 3cCT had a 5-year PFS of 24% compared with 32% of those treated with MAT followed by ABMT (P = .5).
Intensified therapy improves response rate and prolongs survival of children with disseminated neuroblastoma, although its impact on the eventual cure rate remains to be established.
Test results of heavily irradiated Si detectors Albergo, S; Azzi, P; Babucci, E ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1999, Letnik:
422, Številka:
1
Journal Article
Recenzirano
A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design ...layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300
μ
m thick, p
+ on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10
14
n/cm
2. The detector performances do not significantly change if the detectors are biased well above the depletion voltage.
S/
N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500
V).
The CMS silicon tracker at LHC Bilei, G.M; Albergo, S; Angarano, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
The paper describes the Silicon Tracking System of the Compact Muon Solenoid (CMS) experiment that is foreseen to collect events from p–p collision at the Ecm=14TeV at the CERN future Large Hadron ...Collider (LHC). The proposed system consists of four layers of silicon microstrip detectors placed between the two inner layers of the pixel detector and the outer microstrip gas chamber system. The barrel part covers the η region up to 1.8, instrumenting the central radial region between 20 and 50cm. The forward–backward disks extend the coverage up to η=2.6. This paper will review the main characteristics and performances of the system, the actual status of the R&D activities that we are carrying on, and the status of the milestones we have to fulfill in view of the Technical Design Report expected at the end of the year.
An increasing interest in the behaviour of silicon detectors at cryogenic temperatures has been awakened by the discovery of the so-called Lazarus effect, namely the recovery of charge collection ...efficiency (CCE) by means of cryogenic cooling. We measured the CCEs of three single diodes previously irradiated with different neutron fluences. The current-voltage characteristic were measured at 300 and 77 K, showing that the low-temperature operation considerably decreases the steady-state current. This is also the case when a forward voltage bias is applied, which then becomes a suitable option. At 77 K, in the case of samples irradiated with 5 × 10
14
neutrons cm
−2
, the CCE is completely recovered. A third sample irradiated with 2 × 10
15
neutrons cm
−2
shows a 60% CCE at 250 V forward bias.
Experimental evidence has been found for a filtering effect on the soft electron component in electromagnetic showers when combinations of low-Z and high-Z materials are used as absorbers. The ...filtering effect can be fully exploited to reduce the electromagnetic calorimeter response, making it possible to achieve the compensation condition in a Si/Fe+Pb calorimeter with an effective interaction length almost equal to that of Fe. The action of Fe on Pb, by modifying the critical energy during the electromagnetic shower development, leads to a yield of soft electrons (and very few photons) that are stopped in subsequent absorber layers and/or absorbed by the G10 plates. Recent measurements performed with an enlarged Si/Fe+Pb calorimeter support the idea; the authors have shown that an electromagnetic energy smaller than the hadronic energy is possible once particular FePb configurations are used.< >
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 -50°C after 10 16 1 MeV neutron equivalent fluence.
The PRIMA (PRoton IMAging) collaboration, supported by INFN and MIUR, is realizing a proton Computed Radiography device suitable to acquire the single proton with 1MHz rate for application in proton ...therapy. Its design and the first results obtained are presented.
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