中科院高能物理所核电子学与核探测技术分会年会.ppt

1,李卫国中科院高能物理所2002年12 月2日，厦门,BEPCII/BESIII 工程中国核学会，中国电子学会核电子学与核探测技术分会年会,2,引言BEPCII 设计 BESIII 设计进度和经费预算国际国内合作结束语,3,The BES Collaboration,Korea(4)Korea University Seoul National University Chonbuk National UniversityGyeongsang Nat.Univ.,Japan(5)Nikow UniversityTokyo Institute of TechnologyMiyazaki UniversityKEKU.Tokyo,USA(4)University of HawaiiUniversity of Texas at DallasColorado State University Stanford Linear Accelerator Center,UK(1)Queen Mary University,China(18)高能所；中国科学技术大学；山东大学；浙江大学；华中师范大学；上海交通大学；北京大学；高等科学技术中心；武汉大学；南开大学；河南师范大学；湖南大学；清华大学；辽宁大学；四川大学；江苏师范学院；广西大学；广西师范大学；,4,Data Collected with BESI and BESII,BES 获取的数据,5,BES 有世界最大的 J/和 数据样本(106),J/,6,BEPCII 未来发展的物理窗口,国际高能物理未来发展有两个前沿：高能量前沿：寻找Higgs 粒子，探索超越标准模型的新粒子和新现象。高精度测量前沿：高统计性和小系统误差的测量，检验标准模型，探索超越标准模型的新现象。考虑到国际高能物理最新成果和B工厂的成功运行，BEPC未来发展的物理窗口主要是粲物理精确测量，并探索新物理现象。BEPC 对该能区物理有独特优势，J 和共振峰截面大，阈值区域本底小,是B工厂无法替代的，对QCD的发展，包括微扰QCD和非微扰QCD及其中间区域十分重要，同时能探索新的物理现象，具有重大物理意义。,7,BEPC II 的物理目标,精确测量 J/、(3770)衰变 精密测量 CKM 矩阵 强子 衰变(VP,VT,TP,VS)和 辐射衰变 轻强子谱重子激发态研究D 介子物理:D 和 Ds 分支比和衰变产物 fD 和 fDs 的测量 检验VDM,NRQCD,PQCD,研究 疑难,8,BEPC II 的物理目标（续）,强子产生机制，低能 QCD：R 值精确测量 物理：带电流，测量 m 和 m寻找新粒子:1P1、c、胶球、夸克胶子混杂态、奇异态探索新物理现象:寻找稀有衰变;轻子数不守恒现象;J/和 衰变中的CP 破坏,9,BEPC未来发展方案:BEPCII,精确测量需要:高统计事例 高亮度加速器+高性能探测器 小系统误差 高性能探测器要求BEPC主要运行在J/和区域，产生的截面非常高最佳的选择是对加速器和探测器作重大改进(BEPCII/BESIII)，以相对较少的投入在较短的时间内将亮度增加一个数量级以上.,10,BEPC II 早期设计方案：单环 多束团 麻花轨道 对撞,在现有的储存环内采用麻花轨道，实现 多束团（26)对撞 束团串（263)对撞与 CESR 类似。设计亮度为 31032cm-2s-1，造价估计为4亿元。技术复杂，需要较长的调试时间。,11,粲物理实验研究出现激烈竞争,BES 的重大物理成果引起国际高能物理界对粲物理实验研究的高度重视，成为新热点。美国CESR 原运行在10GeV的B介子能区，由于无法和B工厂竞争，同时看到粲物理实验研究的重大意义，计划安装多个超导wiggler,将能量降到 粲能区。预期亮度为（1.5 3)x1032cm-2s-1。俄罗斯新西伯利亚的VEPP-4M也有类似的计划。BEPC/BES正面临激烈的国际竞争。BEPC II单环方案不能保证BEPC在竞争中的优势地位。,12,BEPC II 双环方案,在 BEPC 隧道 现有的储存环内新建一个储存环。新老两对半环在南北对撞点交叉，形成两个等同的环。国际先进的双环对撞机技术。每个环内储存 93个束团，流强 0.9A。对撞时间间隔：8 ns.在南对撞点 实现大交叉角水平对撞（11 毫弧度）.计算亮度：1033 cm-2 s-1 3.78GeV.在北对撞点建立连接外环的同步辐射运行直通束流管道，在南对 撞区的插入铁安装二极线圈，使同步辐射运行继续使用现有的外环，光束线不变。同步辐射运行：250mA 2.5 GeV，综合性能大幅度提高。大幅度提高探测器性能：BES III.BEPCII 亮度是 CESR 的倍,而且设计优化在J/和,比CESRc的短平快方案的潜力大得多，技术难度比单环小，能确保我们在竞争中的优势。造价约增加50。,13,BEPC 改进:BEPC II 双环方案,14,BEPCII的设计目标,增加束流强度，压缩束团尺寸。,15,双环安装木模研究,16,技术路线和途径,Micro-b:by*=5cm 1.5 cm超导聚焦磁铁,减小耦合阻抗+超导高频腔 sz=5cm 1.5cm,双环:多束团对撞 h400,kb=1 93,(LBEPCII/LBEPC)D.R.=(5.5/1.5)93 9.8/35=96LBEPC=1.010 31 cm-2s-1 LBEPCII=110 33 cm-2s-1,选择适当 ex&优化参量:Ib=9.8mA,xy=0.04,17,BEPCII与BEPC、CESRc的比较,18,关键技术和挑战,注入器改进注入速率:5 mA/min.50 mA/min.研制新正电子源 稳定性和可靠性 Einj=1.55-1.89 GeV 500MHz超导高频系统 超导高频腔技术 功率源和低电平 低温系统,注入系统 磁铁系统 电源系统 真空系统 超导插入磁铁和对撞区 束流测量系统 控制系统,19,注入器-直线加速器的改进,基本要求:正电子注入速率从5mA/min.提高到 50 mA/min.;能量从1.3 GeV 提高到1.55 1.89 GeV;采用45MW速调管，改进微波功率源，更换八节加速管；正电子打靶能量从150 MeV 提高到240 MeV;电子枪流强从5A提高到10A；研制高性能正电子源，提高效率；改进聚焦和轨道校正系统；重复频率从 12.5 Hz 提高到 50 Hz；脉冲宽度从2.5ns减小为1ns；研究 双束团注入的可能性(fRF/fLinac=7/40);,20,提高正电子流强的措施及其提高因子,21,超导高频系统,基本要求：足够高的电压 足够高的功率 抑制耦合束团不稳定性 稳定性和可靠性 技术路线:加强与 SSRF,Cornell和KEK 的合作，应用成熟的工业技术，在研制中掌握技术.,22,超导高频腔 CESR-type Cavity(ACCEL)KEKB-type Cavity(Mitsubishi),IHEP/SSRF高频合作组将对超导腔的设计进行优化，并跟踪腔的制造及其工艺，以便更好地掌握运行和维护技术。,23,3.7 对撞区和超导磁铁,24,BES III 预期年事例数At 1033,at J/and 4.14 GeV,0.61033,25,BESIII 探测器的设计目标,适应高计数率：亮度1033cm-2 s-1 和对撞间隔8ns，硬件触发最高事例率为 4000 Hz，经过三级触发後预期最高事例率为 3000 Hz.改进探测器的分辨率,特别是对光子的分辨率提高粒子鉴别能力加大几何接收度改进对撞区，以便安装超导插入磁铁,26,BESIII 探测器,27,BESIII 的主要改进内容,CsI晶体量能器:E/E 2.3%主漂移室(MDC IV)：小单元，铝丝和 He 基气体 P/P(1GeV)=0.6-0.7%0.8T,0.5%1T,dE/dx=6%飞行时间计数器T:桶部 90 ps；端部 110 ps 计数器(RPC):读出条宽度：4 cm亮度监测器(LM)L/L=3%超导磁铁：1 Tesla,内径 1.32 m,长 3.8 m适应多束团、高亮度的触发和 DAQ 系统新的电子学读出系统：流水线计算机系统:PC farm,机械手带库的数据管理系统,28,Small cell,43layersHe based gas HeC3H8(60:40)Position resolution 130 mMom.Resolution 0.5%at 1 GeV at 1 Tesla 0.6-0.7%at 1 GeV at 0.8 Tesla,主漂移室结构,29,MDC 模型研究,drift velocity measurement,30,飞行时间计数器（TOF）,桶部（Barrel）端部（Endcap）Double layers TOF:(or TOF+CCT)Single layer TOF plastic scintillator(BC-404 or BC-408)same 88 pieces per layer in 2 x 48 piecesR:81 92 cm,Z:135 cmThickness 4 cm,length 240 cm Thick 4 cm,length 45 cmReadout both sides by F-PMT R5924 Readout at one end by F-PMT Time Resolution 90 ps Time Resolution 110 ps Single TOF 100 ps 2on k/separation:1.11.5GeV/c(for polar angle 00 450)For CCT option,need R&D,达到设计指标是一个很大的挑战,31,Barrel TOF 时间分辨Item Time resolution intrinsic for single layer TOF 80psintrinsic for single layer CCT 100psBeam length 15mm，35psTiming uncertainty for multi-bunches 35psMDC extrapolation error 5mm,25psUncertainty for electronics 25psTotal for single layer TOF 100psTotal for single layer CCT 120psTotal for Double TOF 90ps,32,K/分辨,TOF+TOF,TOF+CCT,33,CsI 电磁量能器（EMC）,BARREL 28cm long 15 X0,E/E 2.3%,X 0.55 cm 1GeV Rin 93 cm,Lin 276cm cos=0.83 5280 crystalsENDCAP Zin 138 cm 2 x 496 crystalsTotal 6000 crystals,covering solid angle cos 0.93,34,Schematic of BESIII CsI EMC,35,能量分辨率模拟,36,EMC需采取措施In order to reach design energy resolution,need careful design of EMC and its calibration system,need to control contributing errors to 1%:Control and measure temperature,humidity and measure radiation dose.Reduce material and dead space as much as possible.Measure every crystal(+PD):dimension;light output,likely to use cosmic ray.Calibrate the gain of electronics;calibrate the system using Xe light;offline calibration using data(e/).,37,BESIII 磁场,Option 1 Super-conductingB:1.0 T,L 3.8 mRin 132 cm,Rout 172 cmTechnically quite demanding for IHEP both for coil and cryogenic system,now collaborate with KEK in design.Option 2 normal magnetB:0.8T,Initial invest is smaller,but operating cost(electricity)is higher,And the fake muon rate is higher,38,Muon 探测器,Barrel(L 4.1m)+Endcap:cos 0.9Consist of 9 RPCRin 175cm;Rout 265cmIron plate thickness between:3-8 cm,8 layersRPC thickness(double layer):3.5 cmReadout hits on strips 4 cmtotal weight of iron:500 tons,39,RPC优点：结构简单；好的位置和时间分辨；高效率；小的死区；灵活的读出；大的信号；薄的厚度 Disadvantages:High HV（610KV)，possible sparking;Also big noise due to surface problem;Need R R&DGas:ArF134A(C2H2F4)Iso-Butane(C4H10),TEST,RPC示意图,40,Muon acceptance,Pion contamination,Muon efficiency and pion contamination as function of mom.,GeV,41,对撞区It is very compact at IR,very close cooperation is needed in the designs of detector and machine components at IR Understand the space sharing,the support,vacuum tight Understand the backgrounds from machine and how to reduce them,good vacuum near detector is required-Beam loss calculation(masks)-Synchrotron radiation(masks)-Heating effect(cooling if necessary)Understand the effects of the fringe field from SCQ to the detector performances,the preliminary study shows that,field uniformity should be better than 5%in most of the MDC volume Center of beam pipe will be a double-wall Be pipe,42,触发系统Trigger rate estimation(using the similar trigger conditions)background estimation,with 40 times beam current and half of the beam lifetime,the rough estimation for the background is 80 times the current rate(10-15),or 800-1200 Hz,taking 1500 as a design number Good event rate(at J/psi),At lum.0.61033,good event rate,to be 2000 Hz,Cosmic ray background can almost be negligible,Total peak trigger rate can be 4000 Hz,additional trigger(software)is needed to reduce the event rate to 3000Hz.,43,Level 0 and 1 are hardware triggers,latency 6.0s,Pipeline clock 40 M HzLevel 2 is software filtering using online computing farmBecause fastest detector elementTOF need a time window of about 30 ns,the trigger can identify bunch train only,notindividual bunch,Level 1 with TOF;hardware track finding;EMC clustering,energy balance,total EMC energy;counter hits,44,前端电子学Pipeline scheme is required Requirements For the timing measurement,likely using HPTDC 25 ps for TOF,0.5-1 ns for MDC For charge measurement 1%accuracy for EMC,2%for MDC and TOFTotal number of electronic channels 25000,45,BESIII Electronics specification list Feb.21,2002,Considering multiple hit time measurement,46,数据获取系统（DAQ）Event builder 4000 Hz 12 K bytes 50 Mb/s,There is some uncertainty in event size,aim for 2-3 Mb/s/per readout crateSwitch networkEvent filteringData storageRun controlOnline event monitorSlow control,47,离线计算和分析 Computing,network,data storage,data base,processing management Supporting software package,data offline calibration,event reconstruction,event generators,detector simulation,Substantial manpower needed for software,Total CPU 36000 MIPSData storage 500 Tbytes/y on tapes,24 Tbytes/y on disksBandwidth for data transfer 100 Mbps,48,BESIII 机械尺寸图,Dimensions need final tuning,49,BESIII 和 BESII 性能比较,50,BESIII 和 CLEOc性能比较,Temperature measurement:1000 EMC CsI,600;MDC 16;,150;electronics crates,300;cable rack,100;environment,100;2.Humidity measurement:250 CsI,200;MDC,8;electronics,20;environment,30;3.Low HV of VME crates:500.4.MDC gas：8.5.Voltage of power supply:several.6.Other measurements?Magnetic field;parameters in SC magnet and cryogenics;HV parameters for detectors;radiation dose;He leakage;flammable gas;others.,慢控制系统（slow control）Required measurements from detector and electronics,ONE WIRE BUS can be used to read these signals outProbe/master,doing R&D 64 bit W.A.O（unique code worldwide),12 bit DATETemperature probe:DS18B20,22 RMB/probe humidity probe:LTM8802,150 RMB/probe 1.Humidity range:199%，typical precision:3%.2.Temperature range:-3060，accuracy 0.5 D.C voltage probe:DS2438/LTM8805,several dozens of RMB/probe analog voltage:010V（resolution：0.01V）Light-decoupling between PC and master to reduce noise pickup,LTM4850/2 dual-port RS485 card,53,BESIII 关键技术和挑战 控制本底(和加速器），在高亮度下获取高质量的数据 设计和稳定地运行超导磁场 MDC的稳定地运行(30000 wires),和高动量分辨 EMC 达到高能量分辨，建造中的质量控制和高性能的 刻度系统 TOF 达到高时间分辨，控制各有关因素 DAQ 系统,达到所需的事例选择和数据传输速率，稳定 可靠地运行；流水线的快电子学 大容量的数据存储和处理,54,某些设计还需确定，如TOF是否采用CCT，TOF的电子，EMC的支撑结构，特别是采用什么磁场。离线任务已确定，人员基本落实，总体框架也已选定，需尽快编写投入运行，约定规则，以便软件人员开始程序的编写。经费和工期的关键 经费：量能器；超导磁场；电子学。工期：主漂移室；量能器；超导磁场（包括轭铁）。,55,工程的进展 立项报告已由计委委托国际工程咨询公司评审通过，将上报国务院办公会议审批。可行性报告已完成。正进行工程设计，将于年底或明年初完成。直线的改进已开始。加速器和探测器的设计经过国际专家评审。某些关键设备的设计和国外实验室合作，如超导设备和 低温系统等。,56,工程进度和经费预算,End of 2002 Preliminary Technical Design Report June 2003 R&D and prototype May 2004 BEPC runJuly 2002 June 2006 ConstructionMay 2004 Nov.2004 BESII dismounting and Linac upgrade Nov.2004 Jan.2005 Linac commissioningJan.2005 Apr.2005 SR runApr.2005 Jan.2006 Storage ring assemblingJan.2006 June 2006 Commissioning of storage ringJune 2006 Sep.2006 BESIII detector moved to beam-lineSep.2006 Commissioning machine and detector Very tight schedule,57,BESIII 进度 2001.72003.6 R&D of critical parts 2002.72005.9 Construction of detector components 2003.12004.6 Construction of return yoke 2002.32004.12 Design and construct of superconducting magnet 2004.72004.11 BESII disassembling 2004.122005.3 BESIII iron yoke assembling(with magnet)2005.4 Commissioning of cryogenics 2005.52005.8 Magnet field measurement（with SCQ）2005.92006.1 Assembling of other detector components 2006.22006.6 Commissioning of BESIII detector 2006.72006.8 BESIII moved to beam-line 2006.92006.12 Commissioning of BEPCII+BESIII,某些子系统有可能会推迟,58,BEPCII/BESIII 国际合作,International collaboration played an important roll in BEPC/BES project，Expect to play major roll in the design and construction of BEPCII/BESIII：BNL of US:SC Q magnet;SLAC of US:Key machine technology,design reviews;KEK of Japan:SC cavity and SC solenoid Improve technical excellency and research capability Advice and help in design and construction in various systems;Technical review and follow-up in detector design,construction and commissioning.,59,More Institutes from US and Japan may join,Korea has interest in participating Should form BESIII international collaboration according to international standard:Institutional board;Executive board;Spokesperson;etc.International review/Documentation/video conferencing,60,BEPCII/BESIII 国内合作,Participation from other Institutes and Universities from China,in charge of one sub-system or collaboration with IHEPShanghai Synchrotron Light Source500 MHz RF system Shanghai Institute of Ceramics：CsI crystalsBeijing University：RF system,detectorQinghua University：Accelerator technique,detectorUniversity of Science and Technology of China：Detector,readout electronics,61,Design,MC simulation Sub-detectors R&D and construction Electronics R&D and manufacture Online/Offline software Software package Reconstructions Calibration Physics study In charge of some sub-system or send people to IHEP,62,结束语,BEPC/BES 在-粲物理上有机遇，也有挑战BEPCII 双环峰值亮度（1.89 GeV）1033 cm-2s-1，同时，对 BES进行重大改造，能保证中国在-粲物理方面保持国际领先水平。BEPCII/BESIII 技术上是可行的，设计已基本完成。BESIII 的设计是国际水平的，很多技术在国内首次实现，是对中国高能物理实验工作者的挑战要加强国际、国内的合作，发挥全国高能物理学界和相关单位的合作，使工程按性能指标、按时完成。在-粲物理上尽快做出一流的成果。,63,谢 谢,64,BESIII 合作组 高能物理所清华大学 北京大学 四川大学 中国科技大学 University of Hawaii,Honolulu 山东大学 上海硅酸盐所 国立中央大学（台北）University of Tokyo,Tokyo University of Washington,Seattle 华中师范大学,65,Infrastructure,BEPCII needs some building construction:halls for Cryogenic system and additional magnet power supplier;improving shielding of some buildings,etc.Major systems:New cryogenic system:capacity of 1kW/4.5KBEPCII power consumption to be doubled110kV transformer:6300kVA 12500kVANew electric crates and apparatusIncrease capacity of air-conditioningImprove water circulation systemImprove pure water system,66,High Energy Physics 1）BEPC future development BEPC II:-BEPC/BES major upgrade,increase luminosity by more than one order of magnitude;-Main physics goal:J/,and D/DS physics;2）Strength non-accelerator experiments:Cosmic ray,astro-physics experiments,neutrino experiment;3）International Collaboration,Chinese Academy of Sciences：The strategy for Chinese HEP and Advanced Accelerator technology,67,Science-education Leading Group of State Council,the 7th meeting(2000.7.27),discussed the report by CAS about HEP Conclusions：（1）Approval in principle of Report about the future development of Chinese HEP and advanced accelerator technologyby CAS.Meanwhile,CAS should consult further with experts in China and abroad，strength and attract more international collaboration.（2）In view of the success of BEPC,approval of major upgrade of BEPC,with a budget of 400 M RMB.With relatively small invest,continue to obtain high-level achievements.(At that time,it was meant single-ring),68,BESIII Mechanical design and Detector HallDetector on two rail pads to move in south-northIron Yoke Barrel 285 tons;endcap 252 tons.,at both sides between barrel and endcap,there should be a slot of 1100 x 80mm for each side of octagon on every terminal surface of the barrel of yoke,for cable space.,69,Assembled Structure,test assembling at factory,70,Movable endcap yoke;reposition for field stabilityendcap EMC supporting and moving design,removing and reconnecting cables should not change the gain.,71,Arrangements of electronic crates,moving with detector,72,Arrangements for cooling water,gas,cables,