Early Career Internal Review Upgrade and development for calorimetry for Deeply Virtual Compton Scattering Alexandre Camsonne VI. Nuclear Physics (NP)

Early Career Internal Review Executive Summary/Abstract The structure of the nucleon is one of the main research axis at Jefferson Laboratory. General Parton Distributions (GPDs) are a generalization of the concept of Form Factor and parton distributions which are defined as limit of General Parton Distributions. The GPDs give an additional spatial dimension to our knowledge of the parton in the nucleon and could solve the spin crisis once measured. The Hall A experiment was able to measure of absolute cross section for DVCS using a calorimeter associated with Flash ADCs this is the most direct measurement to access GPDs. The experience from the previous experiments showed that the background in the calorimeter was a limiting factor for resolution and luminosity. Improvement in calorimetry radiation and background hardnessness is crucial for the 12 GeV program.

Early Career Internal Review Specific Scientific Aims Continue the Lead Fluoride PbF2 effort for 12 GeV Hall A experiment Upgrade electronics to reduce effect of background on resolution Investigate possibility of use of gaseous detector as replacement of PMT to eliminate PMT aging issue due to background. Investigate sampling calorimeter using Micro Pattern Gaseous detector by making a small prototype. By design this kind of detector is less sensitive to low energy background but energy resolution at Jlab range should be determined an optimized. Build full size calorimeter and evaluate performance in beam and compare to PbF 2 during Hall A DVCS experiment.

Early Career Internal Review Research Impact and Benefits Impact and benefits for Jefferson Lab Improved quality of and efficiency of data taking, for any experiment using calorimetry at 12 GeV and beyond by providing radiation hardness, low downtime and an increased in luminosity treatment of background for improved resolution in high background conditions. This will open the way to studies of low counting rate channels such as Double DVCS or J/psi production Impact and benefits for Nuclear Physics High radiation hardness calorimetry will be useful for many other experiment requiring calorimetry in hostile environment such as EIC and other high energy facilities. Impact and benefits for Office of Science Gaseous photodector can also be a cheaper alternative to PMTs which could be used in medical application.

Early Career Internal Review Resources Needed Funding : Manpower 125 K$ a year Procurement : 375 K$ a year PI 50% of work charge (35 K$ year ) Additional man power to complete the project : 1 Jlab Designer for calorimeter redesign for 2 years 1 postdoc hired 100 % on grant ( 50 K$ year ) 1 PHd student funded by grant (25 K$), 2 PhD student by collaborating Universities Collaborators : CEA Saclay, Old Dominion University 1 professor, Ohio University 1 professor, IPN Orsay 1 staff scientist Ressources : Machine shop, detector group, electronic group, test lab, clean room

Early Career Internal Review Schedule and Milestones M : Milestone R : resultQ1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Electronics upgrade 50 K$ M Procurement PbF2 100K$ 200K $ 100K 100K $ M Block selection irradiation tests 12.5 K$ M Redesign of calorimeter20 K$ PbF2 Calorimeter complete M Test run with visible Micromegas with PbF250 K$ R Procure sampling calorimeter prototype lead50 K$ Procure sampling calorimeter prototype electronics50 K$ Prototype building/testing M Prototype Test complete R Procure MGPD for sampling calorimeter 25K$ 200 Procure sampling calorimeter lead50 K$ Procure sampling calorimeter electronics 65 K$ Sampling Calorimeter design50 K$ M Sampling Calorimeter frame 50K$M Procure PMTs or build gaseous photon detector M 125K $ Hall A DVCS experiment install Hall A DVCS experiment data taking Hall A DVCS complete R