test on rpc veto detector model anticoincidence detector for daya bay neutrino exp
Download
Skip this Video
Download Presentation
Test on RPC Veto Detector Model —— Anticoincidence Detector for Daya Bay Neutrino Exp.

Loading in 2 Seconds...

play fullscreen
1 / 22

Test on RPC Veto Detector Model —— Anticoincidence Detector for Daya Bay Neutrino Exp. - PowerPoint PPT Presentation


  • 140 Views
  • Uploaded on

Test on RPC Veto Detector Model —— Anticoincidence Detector for Daya Bay Neutrino Exp. Speaker: Jiawen Zhang. 5 June 2006. Outline. RPC Introduction RPC R&D in IHEP Of CAS RPC Performance Study RPC Mass Production for BESIII RPC for Daya bay Neutrino Exp. Precondition and requirement

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Test on RPC Veto Detector Model —— Anticoincidence Detector for Daya Bay Neutrino Exp.' - ada


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
test on rpc veto detector model anticoincidence detector for daya bay neutrino exp

Test on RPC Veto Detector Model—— Anticoincidence Detector for Daya Bay Neutrino Exp.

Speaker: Jiawen Zhang

5 June 2006

outline
Outline
  • RPC Introduction
  • RPC R&D in IHEP Of CAS
  • RPC Performance Study
  • RPC Mass Production for BESIII
  • RPC for Daya bay Neutrino Exp.
  • Precondition and requirement
  • Test Design
  • Test Result
  • Summary
rpc introduction
RPC Introduction

What is RPC?

RPC is composed of two resistive plates with gas flowing between them. High voltage is applied on the plates to produce a strong electric field in the gas. When a cosmic-ray passes through the gas between the two plates, a signal will produce, which is then picked up by the pickup strip and sent to the DAQ system.

  • Advantages:
  • Simple structure
  • Cheap to make a larger area detector
rpc r d in ihep of cas

Oscilloscope traces of 100 triggered cosmic ray registered in a RPC prototype at 8 kV. The average signal amplitude from a pickup electrode is about 400 mV with a 50 Ω termination. No secondary streamers were recorded

RPC R&D in IHEP Of CAS
  • The RPCs for the BESIII Muon tracker detector were constructed by using a new type of phenolic rosinlaminatesdeveloped in IHEP of CAS.
  • The methods of improving surface quality is similar to other bakelite plates, and have been used to construct RPCs elsewhere.
r d long term stability

other experiments

neutron irradiation

Max: 98.8%

neutron irradiation

Beam test

Average: 97.2%

Min: 95.3%

R&D ---- long-term stability
r d humidity effect
R&D ---- Humidity effect
  • During the R&D test, we added water vapor into the gas for about one month. No effects were observed.
  • All the HV connectors to the RPC are covered with insulation glue. Last summer, the humidity was about 80-90% lasting about 2 week in Beijing. We tested the RPC bare chambers and the assembled modules, no problem was found, and we will do more test soon.
r d flammability gas
R&D---Flammability gas
  • The flammability Iso-butane of the mixture gas maybe catch fire, if its proportion is more than 15%.
  • We used the gas mixture of argon:F134a: Iso-butane = 50:42:8, Therefore the problem won’t be avoided with the ventilation requirement for Radon removal.
rpc mass production for besiii
RPC mass production for BESIII
  • Single layer RPC (bare chamber) efficiency ε>95%

Barrel 7.5Kv

Min. 85.6%

Max. 99.02%

Aver.95.39%

Barrel 8.0Kv

Min. 90.38%

Max. 99.2%

Aver.96.4%

rpc mass production for besiii1
RPC mass production for BESIII
  • A new bare chamber single counting rate is below 1000Hz/m2( only training 1-3days), if training for a long time, the single counting rate will be below 500Hz/m2

Barrel 8.0Kv

Min. 0.022

Max. 0.872

Aver.0.130

Barrel 7.5Kv

Min. 0.016

Max. 0.599

Aver.0.095

slide12

RPC mass production for BESIII

  • 2 layers of RPCs form a super layer, ε >98%

Mean 0.98

Average eff: 0.99

the requirements of daya bay neutrino exp
The requirements of Daya bay Neutrino Exp.
  • The anticoincidence detector is used to decrease the cosmic ray background to improve measurement precision

Table 1. Neutrino instance and Cosmic ray flux

According to the design, we know the radius of central detector is 1.6m. And by calculation, the cosmic ray through the detector is 8Hz near site, and 0.36Hz far site.

Taking example of far site, the cosmic ray through 4 modules every day is 4×0.36Hz×3600s×24h=125000>>80

slide14
Anticoincidence detector ε~99.9%, 125(>80) cosmic ray won’t be removed
  • Anticoincidence detector ε~99.99%,

12(~15%) cosmic ray won’t be removed

Most of cosmic ray can be removed by spectrum & time relation of later neutron signal

So the result is acceptable!

the design of detector
The design of detector
  • Requirement
  • Higher efficiency
  • Less noise

But these two factors are contradictions, so the key problem is how to balance the two factors.

A fact is that a water Cherenkov may be used. (efficiency is ~ 95%[1] ,noise <0.1Hz. [2])

the design of detector 2
The design of detector(2)
  • Outer detector scheme
  • Adopt 2 dimension readout
  • RPC operate in streamer mode
  • The gas mixture used as Ar:C2H2F4:C4H10 =50:42:8
  • HV:+4000V,-4000V
  • Single gap, 3 layers in one module
  • Each layer overlapping assembly, no dead space.
  • Each module overlapping assembly too, so between modules no dead space.
the design of detector 3
The design of detector(3)
  • Efficiency and noise
  • Efficiency of each layer is ε ~95%, and adopt choose 2 out of 3 as a hit, their coincidence efficiency is

εeff=ε3+C32 ε2(1- ε)=0.953+3×0.952×(1-0.95)=99.3%

The efficiency of the module with the water Cherenkov is

1-(1- εeff)(1- ε)=1-(1-0.99)(1-0.95)=99.95%

  • The RPC bare chamber noise rate ~800Hz/ m2 , the shaped signal width is τ=100ns=10-7s, so the module noise rate is

3C32r2 τ=3 ×3 X(800)2×10-7=0.576Hz/m2

since the module has 3 layers RPC, so we can do the track for itself. By using the track information, the noise can be reduced to <0.05Hz/m2. If we reduce RPC noise rate to 300Hz/m2, the noise can be reduce to more lower.

In addition, Because the noise of the water Cherenkov is very small, the total noise is

not more than 1Hz!

the design of detector 4
The design of detector(4)
  • the same as BESIII Muon detector.
  • Each FEC can handle 16 channels,and a total of 16 FEC composed a data chain.
  • All the data chains are connected to the VME readout system.
  • A fast-OR signal from each FEC is sent to the trigger system.
  • The primary bitmap signal are transferred from parallel to serial, hence reduce significantly the cables.
  • The width of the shaped signal is 100ns.
  • Electronics and readout
test result 1
Test Result(1)
  • Group 1(have been used as a telescope sys.)

99.5±0.25%

slide20

Test Result(2)

  • Group 2(haven’t used)

99.3±0.4%

summary
Summary
  • RPC is economical for a larger area detector
  • The RPC performance developed by IHEP is excellent, single gap RPC efficiency>95%, noise rate <800Hz/m2, dark current <2μA/m2
  • Adopt 3 layers, 2 dimension readout, RPC and module overlapping assembly, no dead space. Adopt choose 2 out of 3 as a hit, their coincidence efficiency >99%, the noises <0.05Hz/m2
  • Electronics and readout are same to BESIII Muon detector.
reference
Reference
  • Determination of Neutrino Mixing-Angle θ13 Using the Daya Bay Nuclear Power Facilities,version 3.1
  • Preliminary study of Daya Bay reactor neutrino experiment, Yaxuan Sun, Ph.D thesis

The end

Thanks!

ad