- Email: [email protected]
1 slice test detectors
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 439–441
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
Commissioning and performance of the GE1/1 slice test detectors I. Vai ∗, on behalf of the CMS Muon Group Dipartimento di Fisica, Universitá degli Studi di Pavia, Pavia, Italy INFN Sezione di Pavia, Pavia, Italy
ARTICLE
INFO
Keywords: GEM Micro-pattern gas detectors CMS
ABSTRACT We present the status of the commissioning and integration of the GE1/1 slice test detectors into CMS. Ten Triple-GEM detectors were installed at the beginning of 2017 in CMS to obtain installation and commissioning expertise, as well as to demonstrate the integration into the CMS system. The paper will enlight the configuration of the slice test and then focus mainly on the integration activities and status.
Contents 1. 2. 3. 4. 5.
Introduction .................................................................................................................................................................................................... The GE1/1 Slice Test ........................................................................................................................................................................................ Integration into CMS ........................................................................................................................................................................................ Overview of 2018 plans .................................................................................................................................................................................... Conclusions ..................................................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................ References.......................................................................................................................................................................................................
1. Introduction The operational conditions foreseen in High Luminosity-LHC will induce a huge increase of the pileup (up to 200 superimposed interactions) and of the radiation background for the experiments, which will increase linearly with the instantaneous luminosity of the machine. In order to preserve the performance obtained in LHC Run 1 and Run 2, the CMS Collaboration started an overall upgrade program, which foresees the completion of the existing muon stations with new detectors in the high-𝜂 region, where 𝜂 indicates the pseudorapidity. The first of these new stations, called GE1/1, will be installed in the region 1.6 < 𝜂 < 2.2 by 2020 and is expected to reduce the Level-1 muon trigger rate and improve the tracking performance in a harsh radiation environment [1]. The technology selected is Gas Electron Multiplier (GEM) [2], in particular Triple-GEM, whose complete qualification, performed in the last few years of R&D, led to the approval of the installation of the full station [1]. 2. The GE1/1 Slice Test Ten Triple-GEM detectors were installed in the CMS endcap at the beginning of 2017 with the aim of acquiring installation and
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commissioning expertise, as well as proving operability for the system and demonstrating the integration into the CMS online system. Fig. 1 shows the configuration of the chambers installed in CMS: Slot1 contains four GEMINI, i.e. a couple of Triple-GEM detectors, powered through a ceramic divider and read out with VFAT2 [3] chip and optohybrid v2b [4]. In Slot2 instead, the unique GEMINI is powered through a multichannel power supply and, since January 2018, is read out with the new system based on VFAT3b [5] chip and optohybrid v3 [5]. All the chambers are operated in Ar/CO2 70:30. The initial activity of 2017 included a wide study of stability of Triple-GEM detectors into the CMS environment, which proved that both the single channel and the multichannel high voltage (HV) systems are stable at the level of 1%. The low voltage (LV) system, based on v2 electronics, showed a similar behavior. In parallel, an extensive phase of local calibration of the Data AcQuisition (DAQ) system was carried on. The Detector Control System (DCS) was also locally developed: the main structure foresaw the control of HV and LV system, as well as the monitoring of the gas system and environmental parameters. A Finite State Machine (FSM) was then added in order to prepare the system for the operation in central DCS.
∗ Correspondence to: INFN Sezione di Pavia, Pavia, Italy. E-mail address: [email protected].
https://doi.org/10.1016/j.nima.2018.10.057 Received 27 June 2018; Received in revised form 8 October 2018; Accepted 9 October 2018 Available online 13 October 2018 0168-9002/© 2018 Elsevier B.V. All rights reserved.
I. Vai
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 439–441
Fig. 2. Diagram of the GEM partition into the CMS FSM.
the physical node, while Dm is node used to filter the states from the GEM E partition, while the actions coming from CMS are propagated to GEM (Fig. 2). Since the integration, GEMs are following the automation matrix and using the protection system together with the rest of CMS. On the DAQ side instead the main achievement was the inclusion in the global runs, runs fully integrated into the cDAQ infrastructure and whose events are put into the CMS data stream. This was the primary goal of the DAQ activity and was reached at the end of 2017, where GEM were firstly included into cosmics global runs. The inclusion of GEM into the global runs entails also the need of monitoring the quality of data collected as well as the performance of the detectors. The first interface for monitoring of the data quality is the Online Data Quality Monitoring (DQM), which has been deployed for GEM in a very basic version in 2017. A screenshot of the actual version of the GEM Online DQM is shown in Fig. 3. Always on the software side, the correct geometry of GEM Slice Test has been added in the databases and in CMSSW and is going to be validated.
Fig. 1. Overview of the Slice Test detectors installed in the CMS endcap.
3. Integration into CMS The GEM DCS was integrated in CMS at the end of 2017, to allow the operation of the new detectors together with the rest of the system. A new node was introduced into the CMS FSM called GEM, which contains two partitions: GEM E (Endcap) and GEM Dm (Dummy). GEM E is
Fig. 3. Screenshot of the GEM Online DQM after a short cosmic run. The plots for GEMINI01 are empty because these chambers are not yet included in the global run.
440
I. Vai
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 439–441
4. Overview of 2018 plans
was completed. In 2018, the activity is going to be focused on the acquisition and analysis of the first data coming from global runs, in order to evaluate the real performance of the detectors. The installation of the new GEMINI in Slot1 will be particularly interesting, as it mounts both the final high voltage and low voltage systems, giving then direct feedback on the behavior expected from the complete station to be installed in 2019–2020.
The activity in 2018 is in progress on several fronts, in particular the verification of the stability of the detectors is continuing and is mainly focused on the new GEMINI installed in January 2018 in Slot2. An extensive study of discharges and microdischarges probability is also ongoing with the GEMINI in Slot2, powered with the multichannel power supply. The new GEMINI also mounts the latest version of electronics, which will be used also for the entire GE1/1 station. The analysis of its behavior will be then fundamental to understand if the detectors will operate as expected during the next LHC runs. In parallel, the Prompt Feedback Analysis (PFA) group is analyzing the first data coming from the local and global runs to verify the performance of the detectors. Examples of study ongoing are the identification of dead channels, the noise characterization and the correlation between the hits coming from Cathode Strip Chambers (CSCs) and GEMs. Finally, the new GEMINI is going to be completely integrated in the DCS and DAQ system in order to be able to operate and take data together with the other detectors.
Acknowledgments We gratefully acknowledge the support from FRS-FNRS (Belgium), FWO-Flanders (Belgium), BSF-MES (Bulgaria), BMBF (Germany), DAE (India), DST (India), INFN (Italy), NRF (Korea), LAS (Lithuania), QNRF (Qatar), and DOE (USA) and the RD51 collaboration. References [1] CMS Collaboration: CMS Technical Design Report for the Muon Endcap GEM Upgrade, CERN-LHCC-2015-012 ; CMS-TDR-013. [2] F. Sauli, GEM: A new concept for electron amplification in gas detectors, Nucl. Instrum. Methods A 386 (1997) 531. [3] P. Aspell, et al., A front-end system on chip providing fast trigger information, digitized data storage and formatting for the charge sensitive readout of multichannel silicon and gas particle detectors, TWEPP07, Prague, Czech Republic, 3-7 September 2007, p. 292. [4] T. Lenzi, et al., A 𝜇TCA based data acquisition system for the Triple-GEM detectors for the upgrade of the CMS forward muon spectrometer, JINST, 2017, 12 C01058. [5] J. Rosa, Characterizing the VFAT3 chip for the DAQ electronics of the CMS detector (Master Thesis), www.iihe.ac.be/publications/MasterThesis_ROSA.pdf.
5. Conclusions The slice test has been a fundamental test bench for the installation and integration of the new GEM system in CMS. In 2017, the GEM detectors showed stable performance and the software integration
441
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
Commissioning and performance of the GE1/1 slice test detectors I. Vai ∗, on behalf of the CMS Muon Group Dipartimento di Fisica, Universitá degli Studi di Pavia, Pavia, Italy INFN Sezione di Pavia, Pavia, Italy
ARTICLE
INFO
Keywords: GEM Micro-pattern gas detectors CMS
ABSTRACT We present the status of the commissioning and integration of the GE1/1 slice test detectors into CMS. Ten Triple-GEM detectors were installed at the beginning of 2017 in CMS to obtain installation and commissioning expertise, as well as to demonstrate the integration into the CMS system. The paper will enlight the configuration of the slice test and then focus mainly on the integration activities and status.
Contents 1. 2. 3. 4. 5.
Introduction .................................................................................................................................................................................................... The GE1/1 Slice Test ........................................................................................................................................................................................ Integration into CMS ........................................................................................................................................................................................ Overview of 2018 plans .................................................................................................................................................................................... Conclusions ..................................................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................ References.......................................................................................................................................................................................................
1. Introduction The operational conditions foreseen in High Luminosity-LHC will induce a huge increase of the pileup (up to 200 superimposed interactions) and of the radiation background for the experiments, which will increase linearly with the instantaneous luminosity of the machine. In order to preserve the performance obtained in LHC Run 1 and Run 2, the CMS Collaboration started an overall upgrade program, which foresees the completion of the existing muon stations with new detectors in the high-𝜂 region, where 𝜂 indicates the pseudorapidity. The first of these new stations, called GE1/1, will be installed in the region 1.6 < 𝜂 < 2.2 by 2020 and is expected to reduce the Level-1 muon trigger rate and improve the tracking performance in a harsh radiation environment [1]. The technology selected is Gas Electron Multiplier (GEM) [2], in particular Triple-GEM, whose complete qualification, performed in the last few years of R&D, led to the approval of the installation of the full station [1]. 2. The GE1/1 Slice Test Ten Triple-GEM detectors were installed in the CMS endcap at the beginning of 2017 with the aim of acquiring installation and
439 439 440 441 441 441 441
commissioning expertise, as well as proving operability for the system and demonstrating the integration into the CMS online system. Fig. 1 shows the configuration of the chambers installed in CMS: Slot1 contains four GEMINI, i.e. a couple of Triple-GEM detectors, powered through a ceramic divider and read out with VFAT2 [3] chip and optohybrid v2b [4]. In Slot2 instead, the unique GEMINI is powered through a multichannel power supply and, since January 2018, is read out with the new system based on VFAT3b [5] chip and optohybrid v3 [5]. All the chambers are operated in Ar/CO2 70:30. The initial activity of 2017 included a wide study of stability of Triple-GEM detectors into the CMS environment, which proved that both the single channel and the multichannel high voltage (HV) systems are stable at the level of 1%. The low voltage (LV) system, based on v2 electronics, showed a similar behavior. In parallel, an extensive phase of local calibration of the Data AcQuisition (DAQ) system was carried on. The Detector Control System (DCS) was also locally developed: the main structure foresaw the control of HV and LV system, as well as the monitoring of the gas system and environmental parameters. A Finite State Machine (FSM) was then added in order to prepare the system for the operation in central DCS.
∗ Correspondence to: INFN Sezione di Pavia, Pavia, Italy. E-mail address: [email protected].
https://doi.org/10.1016/j.nima.2018.10.057 Received 27 June 2018; Received in revised form 8 October 2018; Accepted 9 October 2018 Available online 13 October 2018 0168-9002/© 2018 Elsevier B.V. All rights reserved.
I. Vai
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 439–441
Fig. 2. Diagram of the GEM partition into the CMS FSM.
the physical node, while Dm is node used to filter the states from the GEM E partition, while the actions coming from CMS are propagated to GEM (Fig. 2). Since the integration, GEMs are following the automation matrix and using the protection system together with the rest of CMS. On the DAQ side instead the main achievement was the inclusion in the global runs, runs fully integrated into the cDAQ infrastructure and whose events are put into the CMS data stream. This was the primary goal of the DAQ activity and was reached at the end of 2017, where GEM were firstly included into cosmics global runs. The inclusion of GEM into the global runs entails also the need of monitoring the quality of data collected as well as the performance of the detectors. The first interface for monitoring of the data quality is the Online Data Quality Monitoring (DQM), which has been deployed for GEM in a very basic version in 2017. A screenshot of the actual version of the GEM Online DQM is shown in Fig. 3. Always on the software side, the correct geometry of GEM Slice Test has been added in the databases and in CMSSW and is going to be validated.
Fig. 1. Overview of the Slice Test detectors installed in the CMS endcap.
3. Integration into CMS The GEM DCS was integrated in CMS at the end of 2017, to allow the operation of the new detectors together with the rest of the system. A new node was introduced into the CMS FSM called GEM, which contains two partitions: GEM E (Endcap) and GEM Dm (Dummy). GEM E is
Fig. 3. Screenshot of the GEM Online DQM after a short cosmic run. The plots for GEMINI01 are empty because these chambers are not yet included in the global run.
440
I. Vai
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 439–441
4. Overview of 2018 plans
was completed. In 2018, the activity is going to be focused on the acquisition and analysis of the first data coming from global runs, in order to evaluate the real performance of the detectors. The installation of the new GEMINI in Slot1 will be particularly interesting, as it mounts both the final high voltage and low voltage systems, giving then direct feedback on the behavior expected from the complete station to be installed in 2019–2020.
The activity in 2018 is in progress on several fronts, in particular the verification of the stability of the detectors is continuing and is mainly focused on the new GEMINI installed in January 2018 in Slot2. An extensive study of discharges and microdischarges probability is also ongoing with the GEMINI in Slot2, powered with the multichannel power supply. The new GEMINI also mounts the latest version of electronics, which will be used also for the entire GE1/1 station. The analysis of its behavior will be then fundamental to understand if the detectors will operate as expected during the next LHC runs. In parallel, the Prompt Feedback Analysis (PFA) group is analyzing the first data coming from the local and global runs to verify the performance of the detectors. Examples of study ongoing are the identification of dead channels, the noise characterization and the correlation between the hits coming from Cathode Strip Chambers (CSCs) and GEMs. Finally, the new GEMINI is going to be completely integrated in the DCS and DAQ system in order to be able to operate and take data together with the other detectors.
Acknowledgments We gratefully acknowledge the support from FRS-FNRS (Belgium), FWO-Flanders (Belgium), BSF-MES (Bulgaria), BMBF (Germany), DAE (India), DST (India), INFN (Italy), NRF (Korea), LAS (Lithuania), QNRF (Qatar), and DOE (USA) and the RD51 collaboration. References [1] CMS Collaboration: CMS Technical Design Report for the Muon Endcap GEM Upgrade, CERN-LHCC-2015-012 ; CMS-TDR-013. [2] F. Sauli, GEM: A new concept for electron amplification in gas detectors, Nucl. Instrum. Methods A 386 (1997) 531. [3] P. Aspell, et al., A front-end system on chip providing fast trigger information, digitized data storage and formatting for the charge sensitive readout of multichannel silicon and gas particle detectors, TWEPP07, Prague, Czech Republic, 3-7 September 2007, p. 292. [4] T. Lenzi, et al., A 𝜇TCA based data acquisition system for the Triple-GEM detectors for the upgrade of the CMS forward muon spectrometer, JINST, 2017, 12 C01058. [5] J. Rosa, Characterizing the VFAT3 chip for the DAQ electronics of the CMS detector (Master Thesis), www.iihe.ac.be/publications/MasterThesis_ROSA.pdf.
5. Conclusions The slice test has been a fundamental test bench for the installation and integration of the new GEM system in CMS. In 2017, the GEM detectors showed stable performance and the software integration
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