The WELL detector Bellazzini, R; Bozzo, M; Brez, A ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1999, Letnik:
423, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We introduce the WELL detector, a new type of position-sensitive gas proportional counter produced using advanced Printed Circuit Board (PCB) technology. The WELL is based on a thin kapton foil, ...copper-clad on both sides. Charge amplifying micro-wells are etched into the first metal and kapton layers. These end on a micro-strip pattern which is defined on the second metal plane. The array of micro-strips is used for read-out to obtain 1-D positional information. First results from our systematic assessment of this device are reported.
The micro-groove detector Bellazzini, R.; Bozzo, M.; Brez, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/1999, Letnik:
424, Številka:
2
Journal Article
Recenzirano
We introduce the Micro-Groove Detector (MGD), a new type of two-dimensional position-sensitive gas proportional counter produced using advanced Printed Circuit Board (PCB) technology. The MGD is ...based on a thin kapton foil, clad with gold-plated copper on both sides. An array of micro-strips at a typical pitch of 200
μm is defined on the top metal layer. Using as a protection mask the metal left after the patterning, charge amplifying micro-grooves are etched into the kapton layer. These end on a second micro-strip pattern defined on the bottom metal plane. The two arrays of micro-strips can have an arbitrary relative orientation and so can be used for read-out to obtain 2-D positional information. First results from our systematic assessment of this device are reported: gas gain
>15
000
, rate capability above 10
6
mm
−2
s
−1, energy resolution 22% at 5.4
keV, no significant charging or aging effects up to 5
mC/cm and full primary charge collection efficiency even at high drift fields.
Thirty-two large-area Micro-Strip Gas Chambers were tested in a high-intensity, 350 MeV pion beam at PSI to prove that we had reached a Milestone for the Compact Muon Solenoid (CMS) experiment. The ...particle rate was approximately
6
kHz/
mm
2
, distributed over the whole active area of the detectors, and this rate was maintained for a total integrated time of 493 h. All of the chambers were operated with signal-to-noise values at or above that corresponding to 98% hit detection efficiency at CMS; the average
S/
N was 31. No indications of any gain instabilities or ageing effects were observed. In the official 3-week Milestone period, three strips from a total of 16
384 were damaged, a result which is 20 times lower than the minimal requirement for CMS. The spark rate of the detectors was very low and decreased with time to an average of one spark per chamber per day. The cathode voltages of 24 of the chambers were increased over a one week period to investigate the behaviour of the detectors at higher gains; the maximum
S/
N value was 2.4 times that at the normal working point. No significant increase in spark rate or strip loss rate was detected and the chambers operated stably. The detector efficiencies and imaging capabilities were also investigated. The MSGC design features and the assembly and test methodologies that enabled us to achieve these results are reported.
We report recent results from the development and testing of two types of micropattern gas detectors—micro-strip gas chambers and GEM-based devices with two types of pixel read-out. Thirty-two ...micro-strip gas chambers were tested in a high intensity hadron beam as a milestone for CERN's Compact Muon Solenoid (CMS) experiment. The detectors were operated with voltage settings corresponding to 98% hit detection efficiency at CMS for a total high intensity exposure period of 493
h. All of the requirements expected by the milestone—gain stability, number of lost strips, spark rate, etc.—were met, with wide margins. In a separate investigation, we have coupled PCB pixel read-out planes to GEM foils. In one case, 2
mm×2
mm pixels were fanned out to individual discriminators and scalers to provide very fast (2
MHz/pixel) read-out; this system has been used as an imaging device to provide diagnostic information in fusion experiments. The second type of device used smaller pixels (200
μm squares) and a Flash-ADC read-out system to reconstruct individual photoelectron tracks. The angular distribution of the tracks allows the polarisation direction of polarised X-ray sources to be identified, with possible applications for future space experiments studying celestial X-ray emissions.
A two-stage, high gain micro-strip detector Bellazzini, R.; Bozzo, M.; Brez, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/1999, Letnik:
425, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A two stage position-sensitive gas proportional counter has been constructed by tightly coupling a Gas Electron Multiplier (GEM) with a Micro-Groove Detector (MGD). The GEM was used as the first ...amplifying stage and was optimised to transmit close to 100% of the primary charge even at very high drift fields (10
kV/cm). Very narrow GEM-MGD separations (0–600
μm) were used so that the active volume of the detector is still very thin (3–3.6
mm) and the required drift field could be maintained using an acceptable drift voltage (around 4000
V). Very high combined gains (up to 3×10
5) were obtained with this system. The detector was found to be spark-free in the presence of HIPs (alpha particles) up to gains in excess of 20
000.
What is the real gas gain of a standard GEM? Bellazzini, R.; Brez, A.; Gariano, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/1998, Letnik:
419, Številka:
2-3
Journal Article
Recenzirano
Odprti dostop
We have observed very high gains (up to 7000) from GEMs with ‘standard’ parameters (kapton thickness 50μm, pitch 120μm, copper hole diameter 65μm, kapton hole diameter 30μm). This was achieved using ...GEMs coupled to a simple array of copper read-out strips. From the measurements of the current on all the electrodes, we conclude that the high observed gains are fully attributable to electron multiplication in the holes of the mesh, and not to electronics related effects as had been previously suggested. Furthermore, we report that this large gain may only be fully exploited when the field in the second GEM gap is high. The effect on the gain of coupling a GEM to another charge amplifying device was investigated using a GEM–PMGC combination.
A set of microstrip gas chamber (MSGC) prototypes, developed for the barrel Tracking Detector of the CMS experiment at LHC, has been tested in a beam. The chambers were 10cm long, with Pestov or ...diamond coated glass substrate. The results on the performance of the chambers are reported. The spatial uniformity of the chambers is also illustrated.
Substrate-less, spark-free micro-strip gas counters Bellazzini, R.; Brez, A.; Latronico, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
Odprti dostop
We review recent work involving micro-strip gas counters with “advanced passivated” cathode strips. We present results from tests of a new variation of the MSGC, the planar micro-gap counter (PMGC), ...with very small (∼10μm) anode–cathode gap. Gains of up to 3×104 were achieved and gain variations due to charging effects were less than 10% using an ordinary (uncoated) boro-silicate glass substrate. The PMGC showed no reduction in gain when subjected to an X-ray flux of 4×105Hz/mm2 and survived exposure to alpha particles equivalent to 75 days’ running at LHC with no signs of strip damage.
A large area, high gain Micro Gap Chamber Angelini, F; Bellazzini, R; Bozzo, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/1995, Letnik:
362, Številka:
2
Journal Article
Recenzirano
Odprti dostop
A new approach to the construction of the Micro Gap Chamber is presented. A 10 × 10 cm
2 MGC has been built using a 8 μm thick polyimide layer as anode-cathode insulator. Studies on gas gain, ...uniformity of response along the strip and charging-up have been carried out in laboratory by using X-ray sources. Very large proportional gains, up to ∼ 210
4, have been reached working with gas mixtures based on Ne-DME. The simplified technology for the detector fabrication opens the possibility to produce very large area MGCs.
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