General Meeting Summary 1/30/14

NPS PROTOTYPE STATUS:

• Ordered PMTs from Hamamatsu and PbWO4 (10) from SICCAS in December 2013. Hamlet will follow up on the status of this order.

• Ordered Nichia (blue) and two sets of high intensity IR LEDs.

• Looking for additional different sets of blue and IR LEDs for the monitoring and curing system

• Looking for drivers for the LEDs (pulsed and continous modes)

• Looking for possibilities to measure the absolute intensity (photons/sec), since need to know absolute power of light source for monitoring and curing, and light intensity delivered to each module

• Trying to gather the HV dividers assembled last year for the prototype

DISCUSSION ON COMPONENTS AND DESIGN OF PROTOTYPE

• DVCS/HA built a matrix of blue LEDs for monitoring and could provide drawings as an example for the NPS. Can also have a look at the setup in the test lab. This should be scheduled with Carlos. Some questions about the LEDs used, e.g., for monitoring? - blue fluorescent light is used for curing

• Some discussion about the power of the red LEDs considered for curing (~10 mW/module, see page 1 in Hamlet's document). Not a big issue for temperature.

• One of main tests for IR curing setup is the sensitivity of PMTs to IR light. Need to determine the quantum efficiency of R4125 >800 nm up to IR

DISCUSSION ON TESTING PROCEDURES FOR PROTOTYPE AND/OR NPS

• Test benefit of heating crystals. Light output reduces at higher temperatures, but higher temperatures may also enhance radiation resistance. Check if there is a reasonable temperature range, perhaps around 40 C?

• Transmittance measurement of crystals

• Test hybrid configuration with PbF2 and PbWO4 crystals

• Please send additional suggestions for tests to Hamlet.

FADC AND TRIGGERING TESTS ON PBF2

• could use FADCs and CTP from DVCS/HA setup to test how the electronics work with PbF2. Concern is that PbF2 pulses faster than scintillator there might be large fluctuation in the integral depending on the timing of the pulse with respect to the FADC clock

• NPS may be built in a hybrid configuration. One question for hybrid design is the case when the cluster goes across crystals - need a strategy for testing

• Need to make list of what can be tested, and what firmware is needed. This also includes requirements for possible tests with beam during DVCS/HA running (Alex)

PAC42 EXPERIMENT PLANNING

• Glasgow/UK applied for a grant emphasizing HA/HC physics

• Discussion about projections for pi0 photoproduction. Error dominated by uncertainty on pi+. Suggestion to look into possibilities for parasitic data from, e.g., Hall A SBS neutron experiment where pions are background.

HALL C MEETING ON 21/22 FEBRUARY

• Talks on instrumentation (prototype curing, fadc/trigger) and on physics (RCS/pi0)

ITEMS FOR NEXT MEETING:

• NPS design and prototype

• Preparation for Hall C meeting

NEXT MEETING: THUR, 13 FEBRUARY at 9AM (EDT)