1. Absolute energy calibration of
32nd ICRC, August 11-18, 2011, Beijing, China
# 1252
Absolute energy calibration of
the Telescope Array Fluorescence Detector
with an Electron Linear Accelerator
Tatsunobu Shibata
Institute for Cosmic Ray, University of Tokyo
(Wed)
Session 3 ( H.E. 1.4 )
32nd ICRC, August.11-18, 2011, Beijing, China

2. Electron Light Source (ELS)
Precise measurement of Energy of UHECR is most important
Proposed a new calibration for Fluorescence Detectors ( FD ) 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　of the Telescope Array ( TA ) = use Electron Beam from　LINAC(ELS) near FD site
ELECTRON BEAM
COSMIC RAY
Item
systematic error of FD
Fluorescence Yield
11 %
Detector
10 %
Atmosphere
Reconstruction
Total Systematic Error
21 %
ELS is located at 100m far from FD
Known beam energy and current = We can calculate energy deposit in the air
We can calibrate all of FD calibration constant = End-to-End Calibration
32nd ICRC, August.11-18, 2011, Beijing, China

3. 32nd ICRC, August.11-18, 2011, Beijing, China
Design of ELS
Output power = 40MeV(Max) ×109e－/pulse x 0.5Hz = 3.2mW
Pulse width = 1μsec
Use Non Frozen water : Propylene Glycol solution
RF System Frequency=2856MHz Output Power～20MW
20kW Cooling Unit
30℃,110L/min RF
40MeV e-
Faraday Cup
Core Monitor
(Current Transfer)
Collimator (SLIT)
Electron Gun 　　　　　　(100keV)
90-deg Bending Magnet
Accelerator Unit
( Buncher, Accelerator Tube, Magnets )
Energy is estimated w/ 90°Bending Magnet
Beam Monitor =
Beam Charge is measured w/ Faraday Cup
32nd ICRC, August.11-18, 2011, Beijing, China

4. Final Figure of ELS in KEK
Construction of ELS was completed in KEK, Feb.’09
32nd ICRC, August.11-18, 2011, Beijing, China

5. ELS Installation in FD Site
Feb-Mar ELS was installed at the FD Site 100m far from FD
Apr.2009 – May Setup the infrastructure of the ELS
Jun-Sep Standby of the ELS Beam Operation
Beam Shot Direction
Radiation Controlled Area
ELS
Concrete Shield ft-thich, 12ft-height
ELS Control Room
Optical LAN cable is connected from FD site.
Generator (80kW)
Power for ELS operation
～50kW
Keep power for Air Condition and Vacuum from generator in FD site.
Cooling Unit Container
Taken the picture in Sep.5th.2010 from top of the FD station
32nd ICRC, August.11-18, 2011, Beijing, China

6. ELS Installation in FD Site
Fluorescence Detectors Station
Beam Shot Direction
100m
ELS
32nd ICRC, August.11-18, 2011, Beijing, China

7. 32nd ICRC, August.11-18, 2011, Beijing, China
Radiation Safety
Administrator : University of Utah
Radiation Protection
Radiation Safety Officer (RSO)
Responsible User(RU)
Onsite-Radiation Safety Officer
(Onsite-RSO)
Onsite-Responsible User
(Onsite-RU)
◆ Need ≧2 persons during Operation
( Onsite-RSO ×1+Onsite-RU ×1 )
◆ All people need license of
Radiation worker in Univ. of Utah
32nd ICRC, August.11-18, 2011, Beijing, China

8. First Shot and Detection by FD
Event Display of ELS Shower
Data : Sept.5th :30 am ( UTC )
Energy : 41.1MeV
First Shot in Sept.2010
DATA
Beam Operation : Sept.2nd -4th
Beam shot into the Sky : Sept. 3rd and 4th
# of Shot into the Sky～1800 pulses　　　　
Output power = 41.1MeV×40～140pC/pulse×0.5Hz
32nd ICRC, August.11-18, 2011, Beijing, China

9. 32nd ICRC, August.11-18, 2011, Beijing, China
ELS Analysis
Concept of Absolute Energy Calibration with ELS
= Comparison of FADC counts
between DATA and Simulation
Real Data
- ELS Data
• Beam monitor ( Energy, Beam Current ), Injection Position(GPS)
- FD Data
• Shower data which is observed with FD(FADC)
• Air condition ( Temperature, Pressure, Humidity ) with Weather Monitor
MC Data
- Shower Generator
• Air shower simulation by using Geant4.9.3.p02
- FD Simulation
• TA Official Software
32nd ICRC, August.11-18, 2011, Beijing, China

10. 32nd ICRC, August.11-18, 2011, Beijing, China
ELS Analysis Status (1)
Y-PMTs(=1～32)
Comparison results
Y-PMT#=1
Y-PMT#=24
Y-PMT#=32
(1) Longitudinal distribution
of ELS beam
<DATA>
Used 612 events took in 5th.Sept.’10
Beam Energy = 41.1 MeV
16PMTs
<MC>
Beam energy = 41.1MeV
Y-axis :
Summation of FADC of 16 PMTs in one Y-PMTs, and Normalized by Total FADC
<Results>
Matching is Good.
32nd ICRC, August.11-18, 2011, Beijing, China

11. 32nd ICRC, August.11-18, 2011, Beijing, China
ELS Analysis Status (2)
Comparison results
(2) Lateral Distribution of ELS beam
■ DATA
Y-PMT#32
Y-PMT#=32
– MC
Y-PMT#=24
Y-PMT#24
Y-PMT#17
Y-PMT#=17
Y-PMTs(=1～32)
Y-PMT#16
Y-PMT#=16
Y-PMT#8
Y-PMT#=8
Y-PMT#1
Y-PMT#=1
<Results> Matching is Good.
32nd ICRC, August.11-18, 2011, Beijing, China

12. 32nd ICRC, August.11-18, 2011, Beijing, China
Summary
Motivation of ELS ( Electron Light Source )
Absolute Energy Calibration by one source 　　　　　　
Sept First Shot was Detected.
ELS Analysis started
Compared Data and MC
Matching of Shape of Longitudinal and Lateral distribution are good.
32nd ICRC, August.11-18, 2011, Beijing, China