Is Bitcoin Cash more secure? I found in https://www.bitcoincash.org/index.html that this technology is 
the world's most robust blockchain but searching for the details that explains why it is so secure I don't find any information. Some one knows a source that probes why this technology is secure and some technical information about the security implemented on it ?
Bitcoin is secured through proof-of-work mining using SHA256 as the mining algorithm. Bitcoin Cash uses the same algorithm, so the specialized ASIC hardware used to mine one coin, could also be used to mine the other. 

PoW coins are susceptible to ‘51% attacks’, which are possible when a bad actor controls a majority of the network’s hashpower. 

So generally, when considering ‘how secure’ a blockchain is, we consider how possible, or likely, it is for a single entity (or a group of colluding entities) to gain control of a majority of the hash power available for a coin. The more hashpower a coin has pointed at it, the more secure we can consider it to be. This is because an attacker would need a larger amount of hashpower under their control in order to enact an attack. 

From fork.lol, we can see that over the last 7 days, the BTC hashrate has been approx 47.3 exahashes/second, while the BCH hashrate has been approx 1.6 exahashes/second. 

By this measure, Bitcoin Cash is most certainly not ‘more secure’.