Hybrid Gaseous Detector Module for CEPC-TPC

Transcription

1 Hybrid Gaseous Detector Module for CEPC-TPC Huirong QI Institute of High Energy Physics, CAS June 15 th, 2016, Tsinghua University, Beijing - 1 -

2 Outline Requirements of CEPC-TPC Occupancy and simulation Hybrid Gaseous Detector Module Summary - 2 -

3 Requirements of CEPC-TPC - 3 -

4 Requirements of CEPC-TPC Critical Physics requirements for CEPC tracker Detector Goal similar as the ILD Position resolution Momentum resolution - 4 -

5 ILC and CEPC (primary different) Supported by 高能所创新基金 In the case of ILD-TPC Bunch-train structure of the ILC beam (one ~1ms train every 200 ms) Bunches time ~554ns Duration of train ~0.73ms Used Gating device Open to close time of Gating: 50µs+0.73ms Shorter working time In the case of CEPC-TPC Bunch-train structure of the CEPC beam (one bunch every 3.63µs) No Gating device with open and close time Continuous device for ions Long working time 554ns Close time open 0.73ms 50us One train (1321Bunches) 200ms 3.63us Beam structure of ILC Beam structure of CEPC time NO Gating device! - 5 -

6 Simulation: Ion back flow In the case of ILD-TPC Distortions by the primary ions at ILD are negligible Ions from the amplification will be concentrated in discs of about 1 cm thickness near the readout, and then drift back into the drift volume Shorter working time 3 discs co-exist and distorted the path of seed electron The ions have to be neutralized during the 200 ms period used gating system In the case of CEPC-TPC Distortions by the primary ions at CEPC are negligible too 300 discs co-exist and distorted the path of seed electron The ions have to be neutralized during the ~4us period continuously IP IP Ez 3 trains 2 trains 1 trains Amplification ions@ilc Ez 300 trains trains Amplification ions@cepc z z r r 1 trains - 6 -

7 CEPC and ILD TPC (different) Calibration for the distortion Complex MDI design Short L* QD0, LumiCal will inside in the drift length E field distortion in drift length B field distortion in drift length E B efforts Laser alignment and calibration for readout module, pad, PCB and assembled Overview of the MDI Design@ ILC Overview of the MDI Design@ CEPC NEED Calibration of E/B! - 7 -

8 Occupancy and simulation - 8 -

9 Estimation of event rate in TPC Event rate estimation Inclusive Xsec: 5*10^4 fb Assume the inclusive Hit Multiplicity & Polar angle distribution is similar to that of vvh (Not a good assumption!!) Event Rate 250 ifb per IP per year ~ 1.25E7 second per year: 2E-5 ifb per second 1 event Per Second!! NO background considered! From Dr. Ruan Manqi s Simu

10 Beamstrahlung (e+e- pairs) Pair production Hadronic background Lost Particles (Beam Halo) Radiative Bhabha Beamstrahlung Beam-Gas Scattering Synchrotron Radiation More than 100keV of Gamma (No damage or effect for working gas) Just consider at endcap (readout and modules for TPC) Hit density ~1 hits cm -2 BX -1 (From Qing Lei s Simu.)

11 Occupancy CEPC Voxel occupancy Very important parameter of TPC could determine to use or NOT as the tracker detector No consideration for the beam collimator and synchrotron radiation, the value might larger TPC voxel occupancy simulated in TPC radius

12 Simulation of occupancy Very important parameter for TPC Detector structure of the ILD-TPC like ADC sampling 40MHz readout Time structure of beam: 4us/Branch CLIC_ILD 1 6mm 2 Pads CLIC_ILD ~12%@3TeV 1 1mm 2 Pads NO TPC Options! Beam Induced Backgrounds at CEPC@250GeV(Beam halo muon/e+epairs)+γγ hadrons with safe factors( 15) Value of the occupancy inner radius smaller Optimization for the pad size in rφ Simulation of background 1 6mm 2 Pads Simulation of background 1 1mm 2 Pads Preliminary of occupancy

13 Critical challenge: Ion Back Flow High performance requirements by the TPC relies strongly on the quality of the electric field in the drift volume Ions drift back into the gas volume in CEPC TPC Many such the discs in the chamber with ions Ions could reduce the momentum resolution along the drift length Ions should have to be neutralized Ions TPC From Fujii s slice High X-ray dose to reduce the Double GEMs IHEP

14 Hybrid Gaseous Detector Module

15 New ideas for the ions? Ions Our group was asked to think on an alternative option for CEPC TPC concept design And we did our best We proposed and investigated the performance of a novel configuration for TPC gas amplification: GEM plus a Micromegas (GEM+Micromegas) Hybrid micro-pattern gaseous detector module IBF of GEM GEM+Micromegas detector module GEM as the preamplifier device GEM as the device to reduce the ion back flow continuously Stable operation in long time IBF of Mciromegas

16 Hybrid structure module option Short drift length Long drift length track electrons electrons electrons electrons X-ray electrons electrons Measurement method: X-ray and particles track in the module

17 Test of the new module Supported by 高能所创新基金 Test of GEM+Micromegas module Assembled with the GEM and Bulk-Micromegas Active area: 50mm 50mm X-tube ray and X-ray radiation source Simulation using the Garfield Ion back flow with the higher X-ray: from 1% to 3% Stable operation time: more than 48 hours Separated GEM gain: 1~10 Photo of the GEM+Micromegas Module with X-ray

18 Energy 55 Fe Source: 55 Fe, Gas mix: Ar(97) + ic 4 H 10 (3) Gain of GEM: ~5.2 An example of the 55Fe spectra showing the correspondence between the location of an X-ray absorption and each peak

19 Working voltage optimization Optimized operating voltage To achieve the higher electron transmission in the hybrid structure module The ratio of E_avalanche and E_transfer of Micromegas detector is The ratio of E_transfer and E_drift of GEM detector is mm 1.4mm E_drift E_transfer E_avalanche Electron transmission in GEM and Micromegas

20 Gain and energy resolution Test with Fe-55 X-ray radiation source Reach to the higher gain than standard Micromegas with the pre-amplification GEM detector Similar Energy resolution as the standard Micromegas Increase the operating voltage of GEM detector to enlarge the whole gain

21 Discharge and working time Test with Fe-55 X-ray radiation source Discharge possibility could be mostly reduced than the standard Bulk- Micromegas Discharge possibility of hybrid detector could be used at Gain~10000 To reduce the discharge probability more obvious than standard Micromegas At higher gain, the module could keep the longer working time in stable

22 IBF preliminary result Test with using the Hybrid module Charge sensitive preamplifier ORTEC 142IH Amplifier ORTEC 572 A MCA of ORTEC ASPEC 927 Mesh Readout Gas: Ar-iC4H10(95-5) Gain: ~

23 IBF VS E/V IBF vs. Voltage across GEM foil IBF vs. Drift Field Expt. value higher that the simulation data. Contribution to the drift current from the ions from primary ionization( in the Drift region). With the increase of drift field: a) current on drift cathode increases, b) current on the top electrode of GEM decreases, c) sum of the above two remains about the same, d) current on mesh keeps stable

24 Summary and outlook Baseline design for the precdr with an ILD-like strurcture Critical requirements for CEPC Beam structure Obvious distortion Complex MDI design Some activities and simulations Simulation of the occupancy of the detector, the hybrid structure gaseous detector s IBF Hybrid structure detector Some preliminary IBF results Design and test of the detector prototype for the laser calibration The international workshop of the CEPC TPC detector will be scheduled in September, And next development (CDR, or TDR etc. )

25 Thanks very much for your attention!