Latest Results from T979: PSec Time-of-flight Erik Ramberg All Experimenters Meeting September 8, 2008

PSEC Test Beam Community Goal is to develop affordable time of flight measurement for single particles to better than 10 psec University of Chicago Camden Eartley Henry Frisch Heejong Kim Jean-Francois Genat Andrew Kobach Tyler Natoli Fukun Tang Scott Wilbur Argonne National Laboratory John Anderson Karen Byrum Gary Drake Ed May Fermilab Michael Albrow Erik Ramberg Anatoly Ronzhin SLAC Jerry Va’vra

Technique Our weapon of choice is the Micro-Channel-Plate PhotoMultiplier Tube (MCP-PMT). We use two in series and measure the time-of-flight difference for 120 GeV proton beam Cerenkov radiation is crucial for fast timing, so we use quartz radiators coupled to the PMT window (although the PMT window alone can act as the radiator) To retain timing characteristics, we need multi-anode parallel readout. We are investigating 64 and 1024 isochronos anode boards. All measurements reported here are from a simple passive sum of 4 out of 64 anode pads.

Electronic Measurement MCP/PMT’s Anode signal Scintillator Trigger Constant Fraction Discriminators (CFD)* Time to Analog Convertors (TAC)* START STOP 14 bit CAMAC ADC’s * * = Ortec electronics NIM signals 10 bit CAMAC ADC’s Analog Output

Argonne Laser Lab Results: 408nm Results: 635nm ~13 psec at 40 photoelectrons Results: 635nm ~20 psec at 40 photoelectrons

MTest Results from Split Signal from one MCP/PMT st= 6.4 ps ADC1 should = ADC2 This is evidence of noise and differential non-linearities Timing noise level per channel = 4.6 ps

Results from Photonis 25 mm Pore MCP/PMT st= 21.3 ps Cut out tails of ADCs st= 18.6 ps st(device+noise) = 13.1 ps Apply small PH slewing correction st= 19.4 ps st(per device, excluding noise) = 12.3 ps

Analysis of 10 mm Photonis Tube Smaller pore size does not automatically achieve better resolution. We are likely limited by photon generation

st(Photek + electronics) = 11 ps Results for Photek single channel MCP-PMT 210 (10 mm diameter, 5 mm pores) - Radiator is simply the 5 mm quartz window. st(Photek + electronics) = 11 ps st(Photek alone) = 9.6 ps ~ $15K – 20K each! Better timing resolution from smaller pore size AND large light collection area Thanks to Photek (UK) for loan of two PMT210’s !

SiPM Results SiPM = “Silicon PMT”, which is a multi-pixel Geiger mode silicon device for photon counting SiPM’s used is Hamamatsu 3 x 3 mm2 with 6 x 6 x 16 mm3 poly radiator Obtained 47ps timing resolution per device, even with poor light collection on one device 3x3 mm2 1x1 mm2

Other Projects the Group is Working on: Investigating large scale production of very small pore MCP at Argonne Advanced simulation efforts to understand how high speed sampling contributes to resolution Light generation from cone with half-Cerenkov angle, then paraboloid focus to MCP/PMT. Part of FP420 project 10 psec level timing measurement from FPGA board ‘Bump’ bonding of 1024 anode boards