What constitute the secondary particles beam when a high energy proton beam hits a target material? Basically I want to know what particles emerge along with high energy photons(not sure about it) as the second beam when a specific high energy proton beam is incidented upon a target material such as iridium or gold. Can the composition of secondary beam be calculated theoretically? 
Does the ratio of photon energy and particles energy of the secondary beam hold any specific value for a given energy of primary beam?
 A: At the level of complexity suggested by this question, the only reasonable answer is "it depends." Lots of types of particles are produced when hard protons interact with matter, and a clever experimentalist can build an extraction system to focus on any number of them.
The 800 MeV proton accelerator at Los Alamos was built in the 1970s to produce secondary beams of mesons, and for decades was called the "Los Alamos Meson Physics Facility," LAMPF. That program ended and a new target station was built to produce cold neutrons for condensed-matter research. Same accelerator, but now the "Los Alamos Neutron Science Center."
When I was doing a nuclear physics experiment using a neutron beam at LANSCE, we discovered that our beamline had a lot of hard photons that we didn't really want. To characterize our detector's neutron response versus its photon response, we purified the beam by putting stuff in its way. Blocking the beam with a piece of lithium-loaded plastic absorbed most of the neutrons and gave us a pure photon beam; blocking the beam with a wall of lead bricks absorbed most of the photons and gave us the pure neutron beam that we had in mind when we designed the experiment.  But when, as a grad student, I described this process to my high-energy colleagues, they would ask me questions about the kaon component of the beam. Their questions made it clear they were imagining a completely different system for extracting the secondary particles.
A: News to me about the photon. I thought that was still theoretical.
Since we are talking unproven things, the rest of your question is hard to definitively answer. I'm going with pions.
A: Here is an event from LHCb

A proton-lead ion collision observed by the LHCb detector .The  image above shows a typical high multiplicity proton-lead-ion collision event,
The complexity of the outgoing fragments is large, and it constitutes charged tracks from electrons, muons, protons, nuclear fragments,photons ... into jets of particles. No structured secondary beam in this event, and none announced in the data of the experiment.
There exist theoretical models trying to describe the effects , for example this link.
