ILC Si PD ILC The International Linear Collider

ILC Si. PD ILC – The International Linear Collider Project STUDY OF SILICON PHOTODETECTORS Shirley Choi, Keith Drake, Christopher Geraci, Joshua Elliot, Jack Gill, Gleb Oleinik, Uriel Nauenberg, Joseph Proulx, Elliot Smith, Paul Steinbrecher, Jiaxin Yu Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project The Si. PDs we are testing are from Photonique, Switzerland which I think represents the Pulsar Co. in Russia Use a blue light emitting diode onto a 1 mm wave shifting green fiber into the Si. PD. Study of a 5 x 5 cm 2 tile , 2 mm and 1 cm thick with a 1 mm wave shifting green fiber inbedded. Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project SIPD 1 mm sensitive area Bias Voltage 36 -42 volts Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Method of Analysis We scan the pulse train every 2. 5 nsec and record the observed pulse height. The pulses are about 10 nsec wide and all of the light arrives in a ~ 50 nsec period. We use a National Instrument 100 mhz analyzer. We sample four times per 10 nsec interval. Hence we can observe the arrival of the photons within 2. 5 nsec steps. This allows us to choose the gate that fits the particular wave train and this may improve thresolution. We show what happens. Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Noise Pulses in 2 x 105 Triggers Divide by 50 to compare with pulses from signal Very low noise rate 1 2 photoelectrons 3 4 5 Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Pulses from a Blue LED Source Drive voltage =2. 5 V 10 nsec wide ~ 100 hz rate Drive cable and Si. PD readout cable far apart Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project LED Pulse Comparison Significant pulse deterioration Cables somewhat close Cables very close Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Scintillator Tile Pulses; Cosmic Rays 2 mm thick tiles 1 cm thick tiles Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project The Effect of a Variable Gate We can vary the gate so that it does not clip the last pulse and so that it is not so wide that the resolution gets affected by noise pulses. We can see the effect on resolution. Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Pulse early and pulses late Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Pulses close to the best gate width and pulses with a gate too wide Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project We are making measurements as a function of temperature. T= 0 deg. C T= -10 deg. C is similar. Gate 50 -87. 5 nsec Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Next Steps Ø Ø We feel that the poor resolution in the > 4 photoelectrons is due to the coarse sampling rate. Would like to get the gigahertz sampling rate device announced by National Instruments. We can then sample every 0. 125 nsec (using a trick we developed). Would like to develop, in collaboration with Photonique an Si. PD with 2. 5 mm sensitive area and a gain of 10 6. They have this with a gain of 10 5. We need this because we would like to read out three layers at a time with 1 Si. PD to reduce the number of readout elements and associated readout electronics. Continue measurements at cold temperatures t 0 -20 deg C Test devices from Hamamatsu and Sensl Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Univ. of Colorado, Boulder, November 8 2006

ILC Si. PD ILC – The International Linear Collider Project Univ. of Colorado, Boulder, November 8 2006