CERN Radiation Protection group has recently developed a novel radiation survey meter called B-RAD able to operate in the presence of a strong magnetic field. The B-RAD will be equipped with a series ...of probes for gamma dose rate, gamma spectrometry and surface contamination measurements. The feasibility of developing a probe for neutron dose rate and possibly spectral measurements is being investigated. The determination of the breakdown voltage of the SiPM as well as its uniformity between the pixels was performed. The energy resolution of the Cs2LiYCl6:Ce (CLYC) scintillator was measured with the SiPM and compared with two different PMT models: Bialkali and Superbialkali. The temperature sensitivity of the system CLYC + SiPM was measured from -10 to + 40°C.
This paper discusses an instrument intercomparison performed in the high-energy field at the CERF facility at CERN between 2015 and 2017 (October 2015, May 2016, November 2016 and June 2017). ...Measurements were performed in several reference exposure locations with the CERN extended-range Bonner Sphere Spectrometer (BSS), a Berthold LB4611, the LINUS rem counter from CERN, the LUPIN rem counter from ELSE Nuclear, the FHT 762 Wide Energy Neutron Detection Instrument (WENDI-II) from Thermo Scientific, the LUDLUM MODEL 42–41 PRESCILA NEUTRON PROBE and two models of Tissue-equivalent proportional counters (TEPCs) from Far West Technologies. All results are compared with the latest FLUKA reference values from simulations performed in 2017.
•The BSS, WENDI II, LINUS and LUPIN agree amongst them and with the FLUKA simulations within one sigma of uncertainty.•The LB6411 underestimates up to 35% as compared to FLUKA and the extended rem counters.•The PRESCILA overestimates the high-energy component and underestimate the evaporation part. Therefore, the PRESCILA overestimates the H*(10) on the CT and underestimates it on the IT.•Concerning the two TEPC, they agree within their range of uncertainty for all positions. The agreement with FLUKA is satisfactory on the CT/CS but the TEPCs show underestimation on the IT.
We develop and test a model for the longitudinal beam dynamics in an RF-gun consisting in a single and fully analytical transfer matrix. This model deals with the main difficulty of beam dynamics in ...an RF-gun, which is the velocity variation from almost zero to relativistic one along the beam path, by splitting the gun into two zones. A first one, close to the photocathode, where the accelerating field is assumed to be electrostatic. A second one, farther away from the photocathode, where the electron beam is assumed to be ultra-relativistic. We investigate the capability of the model through comparisons with ASTRA simulations, and measurements performed on the PITZ and PHIL facilities. These comparisons show that the agreement with the analytical model is globally good for the cases where the electron bunch has a low density, and is deteriorated when this density increases due to the growing effect of space-charge forces. The agreement with the analytical model is also found to be dependent on the type of RF-gun considered. The comparisons we made also reveal some limitations of the model, for most of which we propose simple practical solutions.
ATLAS calorimetry Puzo, P
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2002, Letnik:
494, Številka:
1
Journal Article
Recenzirano
The ATLAS calorimetry is presented with emphasis on the calorimeter principles. Performances are also shown, including test beam results from the first ATLAS calorimeter modules.
PMF: The front end electronic of the ALFA detector Barrillon, P.; Blin, S.; Cheikali, C. ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The front end electronic (PMF) of the future ATLAS luminometer is described here. It is composed of a MAPMT and a compact stack of three PCBs, which deliver high voltage, route and read out of the ...output signals. The third board contains an FPGA and MAROC, a 64-channel ASIC, which can correct the non-uniformity of the MAPMT channels gain, thanks to a variable gain preamplifier. Its main role is to shape and discriminate the input signals at 1/3 photo-electron and produce 64 trigger outputs. Laboratory tests performed on prototype and pre-series PMFs have showed performances in good agreement with the requirements and have fulfilled the approval criteria for the final production of all elements.
During summer and fall 2004, the response of a full slice of the ATLAS barrel detector to different particles was studied in controlled beam. One module of the ATLAS liquid argon barrel ...calorimeter—identical to the production modules and read out by the final front-end and back-end electronics—was used for electromagnetic calorimetry. This paper presents and discusses the electron performance of the LAr barrel calorimeter, including linearity, uniformity, and resolution with different amounts of material upstream the calorimeter and energies ranging from 1 to 250
GeV.
We are reporting about a scintillating fibre tracking detector which is proposed for the precise determination of the absolute luminosity of the CERN LHC at interaction point 1 where the ATLAS ...experiment is located. The detector needs to track protons elastically scattered under
μ
rad
angles in direct vicinity to the LHC beam. It is based on square shaped scintillating plastic fibres read out by multi-anode photomultiplier tubes and is housed in Roman Pots. We describe the design and construction of prototype detectors and the results of a beam test experiment at DESY. The excellent detector performance established in this test validates the detector design and supports the feasibility of the proposed challenging method of luminosity measurement.
To assess the long-term morpho-functional retinal and choroidal changes in chronic central serous chorioretinopathy (cCSC) pachychoroid eyes in response to continuous oral eplerenone (EPL) treatment.
...This pilot study was conducted on patients with unilateral exudative cCSC. We enrolled a total of 17 exudative cCSC and 17 non-exudative fellow eyes of 17 patients. Baseline best-corrected visual acuity (BCVA) and anatomical (structural optical coherence tomography OCT and OCT angiography) parameters in both eyes were collected at baseline. Follow-up data were collected at 6, 12, and 48 months after initiation of EPL treatment.
(i) Exudative cCSC eyes: Compared with baseline (0.34±0.13 LogMAR), BCVA significantly improved at follow-up examinations (6 months: 0.28±0.13 LogMAR, p=0.039; 12 months: 0.22±0.11 LogMAR, p=0.025; 48 months: 0.21±0.08 LogMAR, p=0.028). Furthermore, there was a significant reduction from baseline in all structural OCT parameters (subretinal fluid and subfoveal choroidal thickness SFCT; p<0.05). (ii) Non-exudative fellow eyes: There was no significant change in BCVA. There was a significant reduction from baseline in SFCT and choriocapillaris flow deficit percentage (p<0.05).
In this pilot study, continuous oral EPL therapy in cCSC pachychoroid eyes resulted in long-term morpho-functional improvement. The beneficial effect of EPL occurred within the first year and was maintained after four years. Based on these preliminary observations, EPL may be effective in the exudative forms of CSC.
We described a one-handed rotational phacoemulsification technique to decrease phaco time and power, and surgical stress on the cornea in eyes with different types of cataract.
In this technique a ...single sutureless corneal incision was made without any side-port incision. After hydrodissection and hydrodelamination were performed, a phaco tip was positioned in contact with the nucleus beside the capsulorhexis edge. By using a peristaltic pump, phacoemulsification was started with high levels of vacuum to keep the probe tip on the edge of the lens and to ensure the rotation of the nucleus, and with low ultrasound energy. The torsional mode used required less occlusion time and volume of fluid. The inclination of the tip was modified to 45-degree, directing it toward the lens center. So the nucleus was aspirated from the periphery toward the center by a rotational movement.
The eye in the technical video had a NC4-NO4 cataract. The preoperative vision in this eye was 20/100 with no improvement with refraction. On postoperative day 1, visual acuity had improved to 20/20. We recorded low intraoperative parameters including ultrasound time (21.4 sec), phacoemulsification power (73%), balanced salt solution used (31 mL) and cumulative dissipated energy (7.27) at the conclusion of the case. After 1 month, Central Corneal Thickness changed from 504 µm to 516 µm, and Endothelial Cell Loss was 1.15%.
This technique uses a single clear corneal incision, high vacuum and low ultrasound power to reduce the exposition to excessive surgical maneuvers, fluid turbulence and ultrasound energy.
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