[CRI RI299] S SFLASH: Absol olute Measurem emen ent o of - PowerPoint PPT Presentation

[CRI RI299] S SFLASH: Absol olute Measurem emen ent o of Fluor ores escen ence ce Yield fro rom Sh Shower P Particles C. Jui 1 , P. Sokolsky 1 , and M. Fukushima 2 . 1 Dept. of Physics and Astronomy, University of Utah, U.S.A. 2 ICRR, University of Tokyo, Japan On Behalf of the sFLASH Collaboration ICRC 2017 Busan, ROK, Jul 13, 2017 1 Version 7, 7/12/2017 12:20pm Korea time

sFLAS ASH Collaborati tion on S. Atwood 1 , K. Belov 2 , J. Belz 1 , P. Chen 3 , C. Field 4 , M. Fukushima 5 , J. J. Huang 3 , M. H. Huang 6 , D. Ivanov 1 , C. C. H. Jui 1 , T.C. Liu 6 , J. N. Matthews 1 , J. W. Nam 3 , M. Potts 1 , K. Reil 4 , B. K. Shin 7 , P. Sokolsky 1 , S. B. Thomas 1 , G. Thomson 1 , S. H. Wang 3 . 1 Dept. of Physics and Astronomy, University of Utah, U.S.A. 2 NASA Jet Propulsion Laboratory (JPL), U.S.A. 3 LeCosPA, National Taiwan University, Taiwan 4 SLAC National Laboratory, U.S.A. 5 ICRR, University of Tokyo, Japan 6 LeCosPA, National United University, Taiwan 7 Faculty of Science, Osaka City University, Osaka, Japan. 2

FLAS ASH ( (~2004) T Thick ck T Target • 2002-2004 the FLASH experiment measured the fluorescence yield from 30 GeV electron beams at FFTB, SLAC 1. Absolute Measurement of 30 GeV electrons (“Thin Target”) 2. Relative Measurements of yield at different stages of shower development (Thick Target: using alumina as variable-depth shower production target) 3

FLA LASH T Thick T Target R Res esult lts Filter Band 310 < λ < 400 nm “None” 370 < λ < 400 nm OF2 330 < λ < 390 nm KG3 330 < λ < 380 nm U360 • FLASH Thick-Target verified that the relative longitudinal fluorescence emission follows the predictions of standard physics expectations 4

New ew E Exper eriment: sFLA LASH @ E ESTA TA sFLASH: Endstation A SLAC LINAC FLASH @ FFTB • FFTB no longer exists • New measurement of absolute fluorescence yield started in 2016 at SLAC in EndStation A (FLASH was run in the old FFTB) 5

Motiv tivatio ion f for or A Absolu olute M Mea easurement • Absolute energy scale is important for the interpretation of the high energy suppression seen in the UHECR spectrum • TA maintains that suppression consistent with GZK cut-off • AUGER has suggested that the suppression is not due to GZK effect 6

New ew S Set etup i in E ESTA Hooverville  John Steinbeck, 1939 7

Variab able De Depth A h Alumina T a Target • Variable Depth shower target made from the same alumina bricks previously used for FLASH Thick- Target. Set up on moving tray (shifts left-right) 8

Shielding • The PMTs are minimally shielded from background radiation using lead bricks – which also restrict/define their field of view 9

Backg kground S Subtrac action • A fan-fold window blind (verified to let no UV light through) is used to block the FOV -- controlled remotely by WIFI from a cell phone in the counting house • Signal = (data with shutter open – data with shutter closed.) 10

Bea eam M Monit itorin ing target A calibrated beam coil is used to measure total primary beam charge, upstream of target. See poster by B. K. Shin (ICRR) et al . (Poster Board 083) [CRI135] The instruments of sFLASH experiment. Jul. 18-19 11

Energy De y Deposition S Simul. • Uses both GEANT and FLUKA based simulation of energy deposition from shower particles in the PMT field-of-view • See Poster by J. J. Huang and T. C. Liu (LeCosPA): (Poster Board 032) [CRD114] Geant4 simulation of sFLASH experiment, Jul. 13-14 12

Data A Analy lysis is • Waveform from each PMT or coil is recorded by digital oscilloscope (Tektronix and LeCroy: BW > 2 GHz) • Charge extracted from integral area of pulses (baseline subtracted) • Mean an error-of-mean extracted from histogram of pulse areas • Apply calibration for coil and PMT 13

VERY P Y PRELI ELIMINARY R Y RESULTS • We did not go beyond ~3 RL because of limitation on radiation levels in ESTA • The results shown use a very simple geometrical calculation of the PMT apertures • A preliminary PMT calibration is used • We show only the results using the GEANT simulation • We show results from only ONE version of “baseline subtraction” • The background radiation subtraction takes (binds-open data) – (blinds-closed data) 14

Energy D Dep eposit itio ion p per er b bea eam el elect ctron Energy Deposition per electron (in primary beam before shower) by shower – calculated by GEANT 15

Pulse areas with Shutter r OPE PEN (Signa nal + + Backg kgrou ound) Left: TA PMT (Hamamatsu) Right: HiRes PMT (Photonis/Philips) identical to those used at TA FD, used at High Resolution Fly’s Eye with pre-amp AND the original FLASH experiment, no pre-amp 16

Pulse areas with Shutter r CLOSED (Background only) y) Left: TA PMT (Hamamatsu) Right: HiRes PMT (Photonis/Philips) identical to those used at TA FD, used at High Resolution Fly’s Eye with pre-amp AND the original FLASH experiment, no pre-amp 17

Pulse areas: OPE PEN – CLO LOSED (Background s subtracted Signal) Left: TA PMT (Hamamatsu) Right: HiRes PMT (Photonis/Philips) identical to those used at TA FD, used at High Resolution Fly’s Eye with pre-amp AND the original FLASH experiment, no pre-amp 18

Cal alcu culated Air Fluoresce scence ce Y Yield (Sig ignal: l: ar arbitrary s scal ale) Left: TA PMT (Hamamatsu) Right: HiRes PMT (Photonis/Philips) identical to those used at TA FD, used at High Resolution Fly’s Eye with pre-amp AND the original FLASH experiment, no pre-amp 19

TO DO DO • Careful comparison of GEANT and FLUKA results for energy deposition • Full ray-tracing simulation of fluorescence emission and propagation to the PMTs • Background subtraction double-checked with “apparent” yield from blinded tubes (blinded cathode) in addition to the blinds-closed data • Complete PMT calibration • Review baseline subtraction procedure • Propose another Beam Run to SLAC? 20

Summa mary • Completed a first run for sFLASH at End Station A, SLAC • We have demonstrated so far the resolving power to see evolution in the fluorescence yield with shower age, if there is any… • Many systematic issues remain to fully understand… • Another beam run at SLAC? Please go see sFLASH posters: • J. J. Huang and T. C. Liu (LeCosPA): (Poster Board 032) Geant4 simulation of sFLASH experiment, Jul. 13-14 • B. K. Shin (Osaka City University) et al . (Poster Board 083) The instruments of sFLASH experiment Jul. 18-19 21