Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an ...Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an optimal endcap radius of225 μm–250 μm, endcap-shield gap of ～ 250 μm, and inter-endcap distance of 540 μm–590 μm. The simulation method for analysis can also be applied to other ion traps, which is useful for improving the design and assembly of ion traps.展开更多
A time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed an...A time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed and set up in our lab and introduced here. The tests during and after the assembly prove that the prototype TPC has been constructed successfully. It is ready for further study.展开更多
A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by ...A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by the new fanning channel, which will degrade the precision of fast control. In this paper, latency uncertainty elimination for the BESIII ETOF upgrade is introduced. The latency uncertainty is determined by a Time-Digital-Converter（TDC） embedded in a Field-Programmable Gate Array（FPGA） and is eliminated by re-capturing at synchronous and determinate time. Compared with the existing method of Barrel-cap TOF（BTOF）, it has advantages of flexible structure, easy calibration and good adaptability. Field tests on the BESIII ETOF system show that this method effectively eliminates transfer latency uncertainty.展开更多
It is proposed to upgrade the endcap time-of-flight（ETOF） of the Beijing Spectrometer Ⅲ（BESⅢ） with a multi-gap resistive plate chamber（MRPC）, aiming at an overall time resolution of about 80 ps. After completi...It is proposed to upgrade the endcap time-of-flight（ETOF） of the Beijing Spectrometer Ⅲ（BESⅢ） with a multi-gap resistive plate chamber（MRPC）, aiming at an overall time resolution of about 80 ps. After completing the entire readout electronics system, some experiments, such as heat radiation, radiation hardness and large-current beam tests, have been carried out to confirm the reliability and stability of the readout electronics. An on-detector test of the readout electronics has also been performed with the beam at the BEPCⅡ E3 line. The test results indicate that the readout electronics system fulfills its design requirements.展开更多
The prototype of a time digitizing system for the BESⅢ endcap TOF （ETOF） upgrade is introduced in this paper, The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive pl...The prototype of a time digitizing system for the BESⅢ endcap TOF （ETOF） upgrade is introduced in this paper, The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive plate chamber （MRPC） are signaled as LVDS by front-end electronics （FEE） and are then sent to the back-end time digitizing system via long shield differential twisted pair cables. The ETOF digitizing system consists of two VME crates, each of which contains modules for time digitization, clock, trigger, fast control, etc. The time digitizing module （TDIG） of this prototype can support up to 72 electrical channels for hit information measurement. The fast control （FCTL） module can operate in barrel or endcap mode. The barrel FCTL fans out fast control signals from the trigger system to the endcap FCTLs, merges data from the endcaps and then transfers to the trigger system. Without modifying the barrel TOF （BTOF） structure, this time digitizing architecture benefits from improved ETOF performance without degrading the BTOF performance. Lab experiments show that the time resolution of this digitizing system can be lower than 20 ps, and the data throughput to the DAQ can be about 92 Mbps. Beam experiments show that the total time resolution can be lower than 45 ps.展开更多
An automatic clock synchronization method implemented in a field programmable gate array （FPGA） is proposed in this paper. It is developed for the clock system which will be applied in the end-cap time of flight （E...An automatic clock synchronization method implemented in a field programmable gate array （FPGA） is proposed in this paper. It is developed for the clock system which will be applied in the end-cap time of flight （ETOF） upgrade of the Beijing Spectrometer （BESIII）. In this design, an FPGA is used to automatically monitor the synchronization circuit and deal with signals coming from the external clock synchronization circuit. By testing different delay time of the detection signal and analyzing the signal state returned~ the synchronization windows can be found automatically by the FPGA. The new clock system not only retains low clock jitter which is less than 20ps root mean square （RMS）, but also demonstrates automatic synchronization to the beam bunches. So far, the clock auto-synchronizing function has been working successfully under a series of tests. It will greatly simplify the system initialization and maintenance in the future.展开更多
Purpose In order to improve the charged particle identi-fication capability,end-cap time-of-flight(ETOF)detector of the Beijing Spectrometer(BESIII)has been upgraded with multi-gap resistive plate chamber(MRPC)technol...Purpose In order to improve the charged particle identi-fication capability,end-cap time-of-flight(ETOF)detector of the Beijing Spectrometer(BESIII)has been upgraded with multi-gap resistive plate chamber(MRPC)technology,aiming at an overall time resolution of 80 ps for minimum-ionization particles to extend the K/πseparation(2σ)momentum range to 1.4 GeV/c.Methods The previous version of ETOF in BESIII consisted of plastic scintillators.The multi-hit events distort both shape and amplitude of the output signals.MRPC technique was chosen for the BESIII ETOF upgrade as it provides high time resolution and high detection efficiency,is of relatively low cost and is insensitive to neutral particles.Most importantly,the fine segmentation of the MRPC readout stripes can suppress multi-hit events effectively.Results The final design of MRPC module for ETOF is characterized by double-stack(2×6)structure,dual-end readout mode and precision electronics.To batch-produce and test these MRPC modules,a series of tools and production procedures as well as related performance simulation and test methods were developed.Results showed that each MRPC module’s intrinsic time resolution(including the electronics contribution)is around 50 ps and the efficiency is better than 97%.The overall performance of the upgraded ETOF is better than the designed index.The new ETOF has been successfully installed at BESIII and run in 2016.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0304401)the National Development Project for Major Scientific Research Facility,China(Grant No.ZDYZ2012-2)+3 种基金the National Natural Science Foundation of China(Grant Nos.91336211 11634013,11474318,and 11622434)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)the Hubei Provincial Science Fund for Distinguished Young Scholars,China(Grant No.2017CFA040)the Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2015274)
文摘Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an optimal endcap radius of225 μm–250 μm, endcap-shield gap of ～ 250 μm, and inter-endcap distance of 540 μm–590 μm. The simulation method for analysis can also be applied to other ion traps, which is useful for improving the design and assembly of ion traps.
基金Supported by National Natural Science Foundation of China(10575063)
文摘A time projection chamber （TPC） readout by gas electron multipliers （GEM） detector is a very promising candidate for the central tracking system of ILC （International Linear Collider）. A prototype is designed and set up in our lab and introduced here. The tests during and after the assembly prove that the prototype TPC has been constructed successfully. It is ready for further study.
基金Supported by CAS Maintenance Project for Major Scientific and Technological Infrastructure(IHEP-SW-953/2013)
文摘A new fanning topology is proposed to precisely fan out fast control signals in the Beijing Spectrometer（BESIII） end-cap time-of-flight（ETOF） electronics. However, uncertainty in transfer latency is introduced by the new fanning channel, which will degrade the precision of fast control. In this paper, latency uncertainty elimination for the BESIII ETOF upgrade is introduced. The latency uncertainty is determined by a Time-Digital-Converter（TDC） embedded in a Field-Programmable Gate Array（FPGA） and is eliminated by re-capturing at synchronous and determinate time. Compared with the existing method of Barrel-cap TOF（BTOF）, it has advantages of flexible structure, easy calibration and good adaptability. Field tests on the BESIII ETOF system show that this method effectively eliminates transfer latency uncertainty.
基金Supported by Chinese Academy of Sciences(1G201331231172010)
文摘It is proposed to upgrade the endcap time-of-flight（ETOF） of the Beijing Spectrometer Ⅲ（BESⅢ） with a multi-gap resistive plate chamber（MRPC）, aiming at an overall time resolution of about 80 ps. After completing the entire readout electronics system, some experiments, such as heat radiation, radiation hardness and large-current beam tests, have been carried out to confirm the reliability and stability of the readout electronics. An on-detector test of the readout electronics has also been performed with the beam at the BEPCⅡ E3 line. The test results indicate that the readout electronics system fulfills its design requirements.
基金Supported by National Natural Science Foundation of China(10979003,11005107)
文摘The prototype of a time digitizing system for the BESⅢ endcap TOF （ETOF） upgrade is introduced in this paper, The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive plate chamber （MRPC） are signaled as LVDS by front-end electronics （FEE） and are then sent to the back-end time digitizing system via long shield differential twisted pair cables. The ETOF digitizing system consists of two VME crates, each of which contains modules for time digitization, clock, trigger, fast control, etc. The time digitizing module （TDIG） of this prototype can support up to 72 electrical channels for hit information measurement. The fast control （FCTL） module can operate in barrel or endcap mode. The barrel FCTL fans out fast control signals from the trigger system to the endcap FCTLs, merges data from the endcaps and then transfers to the trigger system. Without modifying the barrel TOF （BTOF） structure, this time digitizing architecture benefits from improved ETOF performance without degrading the BTOF performance. Lab experiments show that the time resolution of this digitizing system can be lower than 20 ps, and the data throughput to the DAQ can be about 92 Mbps. Beam experiments show that the total time resolution can be lower than 45 ps.
基金Supported by National Natural Science Foundation of China(10979003,11005107)CAS Center for Excellence in Particle Physics(CCEPP)
文摘An automatic clock synchronization method implemented in a field programmable gate array （FPGA） is proposed in this paper. It is developed for the clock system which will be applied in the end-cap time of flight （ETOF） upgrade of the Beijing Spectrometer （BESIII）. In this design, an FPGA is used to automatically monitor the synchronization circuit and deal with signals coming from the external clock synchronization circuit. By testing different delay time of the detection signal and analyzing the signal state returned~ the synchronization windows can be found automatically by the FPGA. The new clock system not only retains low clock jitter which is less than 20ps root mean square （RMS）, but also demonstrates automatic synchronization to the beam bunches. So far, the clock auto-synchronizing function has been working successfully under a series of tests. It will greatly simplify the system initialization and maintenance in the future.
基金supported by the National Natural Science Foundation of China(Nos.10979003,11675172,U1232206)Chinese Academy of Sciences(No.1G201331231172010).
文摘Purpose In order to improve the charged particle identi-fication capability,end-cap time-of-flight(ETOF)detector of the Beijing Spectrometer(BESIII)has been upgraded with multi-gap resistive plate chamber(MRPC)technology,aiming at an overall time resolution of 80 ps for minimum-ionization particles to extend the K/πseparation(2σ)momentum range to 1.4 GeV/c.Methods The previous version of ETOF in BESIII consisted of plastic scintillators.The multi-hit events distort both shape and amplitude of the output signals.MRPC technique was chosen for the BESIII ETOF upgrade as it provides high time resolution and high detection efficiency,is of relatively low cost and is insensitive to neutral particles.Most importantly,the fine segmentation of the MRPC readout stripes can suppress multi-hit events effectively.Results The final design of MRPC module for ETOF is characterized by double-stack(2×6)structure,dual-end readout mode and precision electronics.To batch-produce and test these MRPC modules,a series of tools and production procedures as well as related performance simulation and test methods were developed.Results showed that each MRPC module’s intrinsic time resolution(including the electronics contribution)is around 50 ps and the efficiency is better than 97%.The overall performance of the upgraded ETOF is better than the designed index.The new ETOF has been successfully installed at BESIII and run in 2016.
